Here's what broke on my 4cycle Troybilt trimmer
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Thanks for watching . This 4 cycle trimmer stopped while running and while diagnosing it it lost all compression. After taking the engine apart the damage was tremendous.
I appreciate your get to the point no nonsense approach, I have been a mechanic for a really long time and small engines are a specialty. I love the super quick high revving response of a 2 stroke, but clearly they have their issues especially the really small ones, and Chinese doesn't help either lol. The comments that claim or assert that 4 strokes are not as reliable isn't even close to true. However build quality plays a huge role! This machine could easily have just been a lemon, BUT looking at the oil tells you a lot about the owner and the working life. Maintenance, especially of your lubrication is essential and especially in a very small engine such as this. The oils viscosity has a life span under normal conditions and unlike a full size engine these smaller engines destroy oil sooner, so checking and changing oil as often as needed should be job one. There is no way to definitively determine exactly what happened here but one thing is a fact, that oil sure didn't help! It running lean (way to much air) will definitely cause over heating, but I would expect to see a hole in that piston not so much the edge, but no way to know that! The spark plug gap being closed is a dead giveaway!
thanks for the information I appreciate it.
Great video. I wish you would have shown the hoses to the carb in a little more detail, but it was enough. I took my trimmer (same exact model) to a shop and they wanted $147 to fix it. I could buy a new one for that, so I paid the diagnostic fee and brought it home. They reassembled it incompletely and incorrectly connected the hoses between the fuel tank, primer bulb and carb. Watching your videos gave me all the information I needed so that I was able to fix the machine for the cost of replacing a missing o-ring they lost and the metering diaphragm, which was probably the original defect. I had it up and running in about half an hour with $10 in parts. Thank you for sharing these details.
Thank you for the comment I'm glad it worked out for you.
"The oil's a little bit dirty."
Looks like it came out of my old '94 turbo diesel Chevy truck!
As for 4-cycle trimmers. I like them. They are quieter and don't require expensive and pita to mix gas/oil mix fuel. But then I didn't buy a Troy-Bilt. I bought a Honda 4-stroke trimmer back around the 2003 era. It still runs perfect to this day. I'm watching this video as I'm trying to diagnose an old 4-stroke 2007 Troy-Bilt that I found while cleaning out my Dad's garage. It's been sitting for at least a decade, hanging upside down. I put some ethanol free gas in it, changed the oil, got all the oil out of the air filter, and in about 20 pulls got the thing running but it's smoking like a chimney. My guess is the exhaust is full of oil.
I agree with your exhaust idea. Thanks for the comment I appreciate it
Your cylinder rings may also be going out
@@nickbussard6089 definitely
Two cycle oil is so easy to mix i dont understand why people complain
That was not a rivet that you drilled out it was a small hex screw. Thanks for sharing this as I am having an issue with the same one.
You are correct. Thanks for the comment I appreciate it
I have the same trimmer, except older with no power start thing. I think I bought in in 2008. It sat in the barn about 7 years when I was hiring a guy to do the lawn. Had to learn how to clean the carb to get it running again. Then the gas tubes and primer failed. Just put new gas lines and a new carb on it. The new carb lets you adjust the idle and run mixture settings. Changed the oil for the first time this year. Runs great now. Need to slow down the idle. You mean you change the oil more than once every 12 years? wow. :) (Yes, I will try to change it more often.)
Its just a suggestion. Thanks for the comment
Good information! I love mine, I've used it a ton without any problems. I rev the hell out of mine and it's actually good for it. It keeps it from overheating.
Thanks for sharing
I appreciate your knowledge, you have a new subscriber.
Thanks again.
Best Regards
I appreciate your subscription. Thank you
I think you have exactly diagnosed the problem because my 4 cycle troy built of the same model is doing the same exact thing. It happened while I was using it.
That's what happened here. Thanks for the comment I appreciate it
If you don't teach you should the level of explanation is awesome I learned alot from just this one video. Thanks!
Glad it was helpful!
I just got a new 4 cycle trimmer. I bench ran it for 1 hour at various speeds at the 30 minute mark I changed oil and added SAE 30 with zinc additives, it runs cool and strong and dose not use oil.
Fantastic you seem well ahead of the pack when it comes to maintenance. Thanks for the comment I appreciate it
My 525 appears to have been built some years before this one. She’s a little stubborn to get started. Sometimes even after just shutting it off and letting it sit, but it’s proven itself to be more capable than the cordless black and decker my old man bought.
nice, thank you BC Nation.
I think you pretty well nailed it. Also could have been a defective piston from the factory. And held on till it finally broke.
that Is a very good possibility. Thank you GDAWG
I have two of these weed eaters. Both have no compression. One has the same wall scarring as yours but without a broken piston. The other has perfect cylinder walls and piston skirts. My conclusion is overheating caused the loss of compression. The engine is apparently not cooled very well.
I totally agree with you. Thank you Doug and Carolyn Koepke for the comment.
Hey Doug, as an actual small engine mechanic, I can say that overheating in 4 cycle engines is almost always a problem with lubrication. Just based on what I saw in the video the oil is 100% to blame. When oil is that black it's lubricating properties are severely diminished which results in piston scratching and overheating AS A RESULT OF FRICTION caused by lack of lubrication from bad oil (not poor design). To give you an idea, good motor oil should be almost transparent. Also most manufactures recommend changing the oil every 30 hours and even sooner depending on the model, something that was clearly not done to this model. Hope this helped, let me know if you hav any questions.
I have the same model with the same problem. Thank you so much for this informative video. I guess I'm going to buy a new one. This was my first 4 stroke trimmer, and I'm guessing I should have changed out the oil more frequently. Lesson learned. Going back to 2 stroke for now though. Who knows, I may just buy a battery operated one.
that's a decent plan. thank you for the comment
Well , I was looking at 4 stroke. Not anymore. I do have a 2 stroke with problems. My new carb should be arriving today ,actually. I do have a backup electric. Works fine? If I buy another one . Electric all the way. Same for my next car. Haha
@@GG-xs8vt that makes sense too
Same trimmer I have and the exact same problem defective junk!
On my first one, 5 minutes out of the box, it started massively burning oil. Sprayed my leg with hot oil. One of the piston rod bolts worked it’s way out and punched a hole in the cast aluminum block. Lowe’s took it back. The person that sold it to me was still working on the floor! You could see daylight straight thru the oil sight glass. The second one I’ve had for two years. But at some point the palls/pauls on the fan became dislodged. Wouldn’t start except via ez start fixture and a drill. The unit aluminum shaft seems to be too thin of a gauge aluminum. Bought the parts to fix the starter.
Yes you just mentioned all the common problems with this model.
My dad has that trimmer and I also have a craftsman 4 Cycle 30cc and that Troy Bilt trimmer will be my backup if I need to service my craftsman trimmer
very nice!
As oil gets old it can loose some of its lubercating properties I suspect the oil was never changed and simply lost its properties essentially running it without oil
That's a good possibility
Oil never wears out, but the additives do.
This is the issue I have with mine. It will be interesting to see if it is the same cause. Glad I didn’t try the jump start option yet.
I hope it's not this bad.
Like how you get to the point,no bull.
Cool thanks
Odd failure. My 4-stroke Craftsman trimmer (B&S engine, I think) still functions just fine after 8 seasons, but it gets fresh oil twice per season. Only takes about 6 ounces. It's in semi-retirement (backup status) because it's just too heavy, even with a shoulder strap. So I bought a new Echo GT225 2-stroke for primary use.
I believe that this unit was neglected before it got to me so it was living on borrowed time.
To the final question posed at 7:40 - I would say they went cheap on the metal used in the piston. Metals are complicated, they can be extremely durable, extremely exotic or on the opposite end, made of chinesium, a special "metal" blend from China that saves a lot of money but is brittle and unreliable. Manufacturers see the chinese price of production and get big smiles on their face at all the savings, but they don't calculate they'll end up with a bullshit product that enrages customers within the first year of purchase. All they focus on is the short term profits and don't anticipate having to yank troy-bilt off their shelves entirely like Lowes just did across the country after selling this crap for a few years and dealing with insane rates of angry calls and returns.
All very good points. Thanks for the comment I appreciate it
Thank You.
You're welcome
That model I believe was made by Murray. The one I had was sold as a Craftsman. They were complete and utter crap. I went through 3 of them in less than 15 month. Had the cooling fan break into pieces, the pull start free-spool and the string heads were junk. See ears replaced the first 2 and then refused any further customer service on the last one. I'll buy Husqvarna next time since all the attachments I have will mate up the same. I do like the 4 cycle though. Hate mixing fuel and oil and only have to carry one gas can for all .
Thank you Chad Johnson for sharing your experience. I appreciate it.
MTD happened to that engine. LOL
Thanks for the comment I appreciate it
That says it all. MTD= Minutes Till Destruction.
A honda wouldn't of done that
I work for them and I wouldn't buy anything they make
As oil get old and dirty it looses its ability to cope with the engine temperature. If you need any engine to last ch age the oil regularly before it go’s as dark as this one .
Dark engine oil means it's holding the carbon and engine wear particles in suspension of the oil. The darker the oil the more carbon in suspension. Oil isn't just for lubrication. It cools the engine friction spots while simultaneously evenly warming the engine during its expansion preventing warping, stress cracks and or seizure. Lube, warm, clean, cool.
Thanks for the detailed view of the plate at the back of the crankshaft about minute 4:00 that is part of the starting unit. My Craftsman E Z Pul vintage 2017 is the same trimmer. My problem was it partly locked up due to some trimmer string that got into the cooling air vent in the front, wrapped itself around the front crankshaft and got snagged into the magneto (I know - HOW did that happen?). Vigorous pull starting on my part eventually BENT the plate starter mechanisms (the little springy things) and cracked the plate, which is unobtanium.
It had been a good runner for 5 years.
PS - anyone reading this that wants to send me a spare plate, let me know.
glad the video helped out
I have a TB6040 XP that I bought new in 2012. The only issue I have had is the lower drive cable broke. The only way to replace the cable was to buy the lower tube and cable. Other than that, the trimmer has worked well. I did have to replace the fuel lines and clean the carburetor. But sense switching to non-ethanol fuel, I have had no fuel related issues. These little 4 cycle engines use such small amounts of oil, I replace my oil twice every season. If I was a lawn maintenance guy, I would change it once a week. I also use 4 cycle small engine oil in all my outdoor power equipment. Air cooled engines need specific additives that liquid cooled automobile engine oil lacks.
you're right with good fuel, and watching the oil, these are great little engines.
I’d say the piston got too hot, welded itself inside the cylinder yet broke itself free. In the process, it began destroying the piston and cylinder and all else in its way. I have a Troy Bilt that the clutch broke on recently. Which tore off pieces of the flywheel. Ultimately, the service shop says that MTD makes cheaper products and I believe it. My trimmer wasn’t ran through the mud, and it was only 5 months old at the time it broke. It’s still under warranty. I’m assuming a broken clutch would be covered.
thanks for the information. Its very possible.
I'd say you're correct. Fuel got leaned out by main jet getting partially blocked at full throttle. then got hot and kaboom.
Thanks I appreciate the comment.
That's only a problem in two strokes
I'm not certain if it is an interference engine or not but I am fairly confident that if the sparkplug came in contact with the piston it would come to a immediate hault. if the crankshaft was able to rotate after the piston came into contact with the sparkplug it wouldn't be able to run because the sparkplug would no longer have any gap for the spark to jump across.it wasn't going to run after the crankshaft made just one revolution. Your engine failure is from piston ring. They expanded and became mechanically welded the the piston. Either from to much carbon in the ring groves, lack of lubrication, gasket failure allowed fuel to become to lean overheating piston causing it to expand faster than the cylinder could expand in unison of it was held wide open throttle.
you pretty much nailed it on the head!
I don't know if mine is older than that one or not. The pull start is towards the front of the unit, not at the back like that one. It really would have been interesting to see what the valves looked like. I enjoy watching the small engine tear-downs and repairs. Subbing to your channel. I've got a couple of old 2 cycle weed eaters that I am going to go back and see if I can get them going now too.
thank you Sonya, I'll keep that in mind the next time I tear down another engine.
Smart dude
I have two of these, bought with known recoil starter issues. The jump starter accessory for a driver suffered a clutch (one-way bearing) failure. The next three starter accessories did the same. The clutch on the AC powered jump started suffered the same failure. I bought two replacement "oil pan assemblies" to repair the recoil starter failures. After changing the first one, the recoil starter would not function. Life is short, I gave up on both. This was discussed in detail with personnel at MTD. They were not particularly remorseful regarding the poor design. I would say never again, but find myself repairing a "free" TroyBilt riding mower for Dad. The "automatic transmission" is an entertaining design exercise.
you are correct, these certainly need to be redesigned
I have a Troy bilt tb415cs 4 stroke weed eater. Same as you, I was pulling on the starter cord because it was not starting. I noticed it starting to lose compression as I was pulling on it. I said screw it because I was going to go get a new one anyway because of this ones hard starting issue. Before I knew it, it had 0 compression. I still have it and haven’t tested into it yet. I think I’ll tear into it on Monday and I’ll update you guys on what I find🥴🥴
would love to hear what happened to it. thanks
INSIDE HOUSE GARAGE after I tore it apart, instead of my piston exploding, my piston rings broke and gashed the side the side of the cylinder walls really bad. The dump just gained a new Troy bilt 4 stroke weed eater😂
@@jacobhixon4054 wow thats some serious damage
I would've pulled the valve cover off first to check the valve adjustment. It's just like a car engine with rocker arms and pushrods.
Just me though....could've had a broken valvespring or a valve dropped into the cylinder.....then you'd know without disassembling the bottom end first.
You are absolutely correct. Thank you for the comment I appreciate it
Either that or a foreign object such as dirt got sucked into the combustion chamber,it could've also been caused by a chunk of carbon on top of the piston crown which gouged the cylinder walls,it is a very common problem in the 2 stroke trimmers as well.
The design in the video is a similar design to the Honda overhead camshaft 4 stroke lawn mower engines,it's a silly design because the cylinder head & cylinder are 1 whole assembly so it makes if difficult to decoke the piston crown & the cylinder heads combustion chamber because the cylinder head cannot simply be unbolted !
Yes you are absolutely correct about the design.
1. Not giving the engine a long warm up time before running at full throttle is very damaging to those engines (AND almost everyone does it) It can and will cause cylinder wall scarring on it's own and loss of compression. 2. That oil is not just "a little dirty" is completely trashed and likely helped usher that engine to an early demise. Oil is cheap and SO easy to tip it out...there's no excuse.
I completely agree with you
I still prefer the mixed oil and gas (non ethanol) usually a little strong on oil.
You and me both. Thanks for the comment I appreciate it
That trimmer looks like it is still pretty new as the gas tank looks great and clear, that looks to be in great condition externally but horrible internally. I wonder how long the customer had it before it stopped working, I would guess less than 2 years. It is sad that trimmer had a failure like that, I have never seen that happen before. These Troybilt 4-cycle trimmers seem like they have some of the most damaging reasons for failing. Now I have seen one that has had a broken camshaft and one that has had a broken piston! Seriously how does the piston break if it is metal? My guess is that Troybilt is just not using good quality materials and they are using more and more aluminum in their engines because it is cheaper to manufacture, but it is much weaker than metal would be. Maybe they are trying to make it as light as a 2-cycle trimmer would be and that could be the reason for more aluminum?
Thank you for the comment and material quality is definitely in question.
i have a Cub Cadet ss470
i think is the Same engine as this one 25cc
Emission Compliant for 150 HRS
better than the Previous troy Bilt 29cc - only 50 Hrs Emission Compliance
Thank you Joni for the comment I appreciate it. I wish this one lasted a bit longer.
I own a TBC625EC it's 5 years old now and it runs fine. Just needed a primer replacement. But I change the oil every 4 runs. Oil is cheap compared to a new trimmer
Wow thats a lot of oil changes but you'll never have a problem. Thanks for the comment I appreciate it
@@INSIDEHOUSEGARAGE it only takes about 3 oz of oil LOL
I believe so. Thanks for the comment
@@INSIDEHOUSEGARAGE I like watching your videos I just subscribed
@@donsivak9546 thank you Don Sivan for the subscription.
This video is a eight minute explanation on why you always buy the extended warranty on a string trimmer .
you're absolutely correct
yes, but it depends on who backs that extended warranty.. manufacturer or vendor? buyer beware. some of these extended warranties are nothing more than false advertising, and when your product blows up in a few months of regular use.. so does that extended warranty.(yea I am looking at you Home Despot)
@@mikem4432 I bought a craftsman four stroke trimmer from sears with the extended warranty . I wound up getting eight to ten new replacement trimmers over the years from sears because if they couldn't repair it in a limited amount of time that's what they would do . When they switched to a local repair center the guy was overwhelmed . One guy in a huge shop filled to the ceiling with broken craftsman lawn and garden stuff ! I lost count of how many four stroke craftsman trimers I've had .
I would think that a poor quality piston casting was to blame or the piston had a hairline fracture when cast causing a break from usage. The oil being black as tar does not help. I never heard or seen a piston do that in a truck or car. Nice job on the video. VF
Thanks and i think you're correct. The damage looks to be in the metal.
This happens in automotive engines fairly often, It can be from a number of reasons but often results in the similar destruction of the cylinder wall with debris throughout the engine.
@@INSIDEHOUSEGARAGE Great minds think alike. Good day IHG
@@victoryfirst2878 thank you
Will you be fixing it? Or are you just going to buy a new trimmer? If you do plan on fixing it, I'd love to see a how too video. Great video as always, keep up the awesome work
Right now I will keep for parts until winter. I will then make a determination if I will repair it. Thanks for the comment I appreciate it .
These trimmers need frequent oil changes whereas they only hold a couple of ounces of oil. And because they run so hot it breaks down the oil. They’ve come out with some pretty good battery units you’re better off.
You are absolutely correct about that. Super high maintenance to make them last.
If you are lazy to mix oil and gas for 2 stroke engines, you can buy bottles of pre-mix oil and gas at the store. I also use premix oil and gas on this 4-stroke engine without any problem. The oil leaked in my 4 -stroke engine. I believe it is due to the plastic attached to the reservoir with only one screw. Two screws can fix the problem. I used jump start with an electric drill and adapter. After several uses, the pull string starter and the fan inside broke apart. I removed the starter string pull start and now is using jump-start only. The only advantage of this engine is that it is easier to start the engine with jump start. Pull start can take many pulls on cold engine.
thanks for the information
Sad to me to say;a new Piston and rings,not to mention the cylinder would be more costly than the trimmer itself...
you are correct
Hi, Outstanding video. Let me guess on what happened...remember this is only a guess. I noticed when you drained the oil it was really dirty. On a scale of one to ten, I would give it at least a nine on how dirty it was.
Again thanks for the video
Vinny aka Chief Bauer
You are correct
Nice video. Good info. Going Electric. Done.
Thanks
I have a young Troy-Bilt 685 that's slightly out of warranty, but lots of hours on it. Yesterday it started great and did 15 minutes of lake edge weeds, then just quit dead. Very little compression (50 psu), Spark plug lots good. I assume it's a valve or cam, so junked it.
that's a shame, a valve lash adjustment might have saved it.
i could be wrong but that locked like one of those expensive $50-90 walbro carbs better hold on to that.
Yes I believe you are correct. I will.
#11 on ebay
I wouldn't buy a four-cycle anyway personally but aside from the oil looking awfully black and thin, (the white cup made it look worse I'm sure) running full throttle for to long is rough on aluminum and I've seen that inside of weed eater brand machines on the flywheel being distorted from overheating. That would be my guess but it takes more than one time to doing that usually.. I Lent a Murray to my stepdaughter who brought it back with oil coming out of the spark plug hole. Mind you this is a brand new weed wacker that I had only run once but she ran it for 2 hours without stopping full throttle and it was done! They fried the darn thing..
yes it's a shame when that happens. Thank you Dwayne Collins
Over revs probably did it in! It got to hot! Are you going sell any parts,I could use that cooling fan! Good video!! Thanks very helpful
I'm keeping for parts too
I wonder if it got tilted to such a degree that the oil was dislocated and got into the piston or in such a position to where it could not oil properly and caused the rod and piston to heat up too much.
I have a Troy Bilt weed eater/ edger. I have no experience with the edger attachment and am concerned about adjusting the edger attachment so as not to tilt the engine too much.
I have wondered the same thing too. Either way 4 cycles definitely have their cons.
How do the pawls look like when you remove them from the flywheel because my troybuilt has like some pegs in it and I’m not sure what goes there
i have since put everything away in boxes so if i can find it i'll let you know
I wish I knew half of what he's talking about 🤣🤣🤣 I guess I'll just start taking it apart. Wish me luck
Good luck
i know I am kind of randomly asking but does anyone know a good website to watch newly released series online ?
@Jimmy Marcel lately I have been using Flixzone. Just google for it =)
@Miguel Alfredo definitely, have been using flixzone for years myself =)
@Miguel Alfredo thanks, I went there and it seems like they got a lot of movies there =) I really appreciate it!
I'm going on about 10 years on my MTD 4 cycle trimmer and It runs great and my oil never looks like that. I only use Mobil 1 in everything i own. My MTD Tractor is 1998 and the MTD snow blower is from 1980. I want to get a new zero turn, Ariens snow blower and a powerful battery trimmer but I won't until they break and I can't fix them
It seems you take really good care of your equipment so they may never break.
I agree with you
thank you William Munday
Man, that's some black oil !
Yes it is. Worst part is that the oil was changed not that long ago.
Didn’t change the oil. But to be fair the construction of the weedeater is one of the cheapest I’ve seen yet
I agree
Oil was burned, the whole system went cherry red, valve seats moved/melted, that rod looked bent, etc. In short...nuked.
Thank you for the comment I appreciate it
That’s damaged very badly. My question to you is could the black oil have anything to do with the engine failure? It looks pretty baf
Yes there is a chance but I have better theory but I really don't want to say it out loud.
I honestly believe it's the oil. That was some thick and nasty stuff and depending on when this trimmer was used if it was in cooler weather that would even make it harder to pump the oil around the engine.
As you're now the consumer who's buying lawn equipment do not think like you and I. They just fill it with gas and when something happens they curse the brand out and in most cases they go by a new piece of equipment. Which for people like you and I that's great that means we are getting ready to get something free lol.
Most of these people could have a lawn mower for 10 years or more and not once ever think about changing the oil. Just look at the air filters you see them as I do completely clogged up and the consumer has no idea how to go about changing that. God forbid if they could figure out how to get the spark plug out that looks like it would be in its own adventure. I had a very good friend of mine bring me over the riding mower talking about how it was given to him and that he had no idea how to get it running. He said he looked at the spark plugs and they were fine. That night when I came back home I wasn't tired so I went out and checked the machine. I don't know how he got the spark plugs out he screwed them in not even halfway. When I was trying to start it I kept on hearing a weird noise that I have never experienced while working on lawn equipment. It was just a fluke that I said to myself look at this plugs yourself.
Of course after fixing his blunder I had it running within the hour typical carburetor clogged up drum roll please nobody bothered to change the air filter and he definitely never changed the oil.
I really do enjoy watching your videos. I have a four cycle weed trimmer that's practically brand new that was given to me from my neighbor when he sold his house. He gave me that and a brand new lawn mower since he wasn't going to need it again. That I'm really interested in taking that apart just to see what it's all about. When I get curious I come out and take things apart on purpose to see how they work and if whatever motor it is would have a problem I would be able to figure it out more quickly.
As always I'm sorry for leaving you such a long response I just love watching these sort of videos and leaving comments and have people writing back. Like I always say also there is more than one way to approach an engine problem and that's one of the biggest reasons that I watch all these videos. Who knows one day I might stop doing all my work for free and have a side hustle going on since I had to retire early and I enjoy fixing things I always have.
Of course I hit the like button and I do look forward to your next video.
thank you David Frank
what causes oil to run thru the breather tube on a 4 cycle troy built weedeater
2 possible reasons, one would be there was more oil in the engine than there should be.
the other reason would be turning the engine on its side while using it.
I believe the failure was due to lack of keeping the oil changed. Oil lost its ability to lubricate properly or was so dirty that it couldn’t be distributed evenly, the machine overheated due to lack of lubrication and fatigued the metal on the piston until it broke away. If you don’t like changing oil, stay with the 2 strokes.
I believe you are absolutely correct which also put some of the blame on the user.
For the question on what I think happened to the engine , I think it was a little bit of what you said and lack of maintenance with how black the oil was it may not have been changed in a while, old oil with dirt and contaminates in it doesn't protect the engine as good as clean oil that's why there's oil change intervals for engines , so I'm thinking it went a little lean or someone set it a little lean and the oil loss some of its cooling and wear protection and then a bang piston broke , could be the cheapness of material but alot of engines and their components are made in China so I'm on the fence with that one
this one was kind of fun and sad all at the same time. turns out they were using the trimmer, on it's side.
@@INSIDEHOUSEGARAGE Oh so it didn't get lubricated properly due to being used on its side , the way the rings and oil looked it made me think the oil didn't do it job
Thanks for the teardown I will never buy a 4-stroke after watching this video stick with a two stroke.
Me either. Just too heavy
The engine design is much better than Ryobi's s430 4stroke with a freaking timing belt...
I have had a Ryobi 4 stroke manufactured in the 90s that still works great, with plenty of compression and zero oil consumption. Other than routine maintenance, the only repairs I've had to do are fuel lines and a carb rebuild.
Just would be great to see you work on one something different maybe a snow blower to but you probably live where there's no snow
me too. what do you need to know about them?
That failure looks similar to some 4 stroke dirt bike engines I’ve seen. Too many hours. When a 2 stroke fails you slap a new piston in and it’s good. When a 4 stroke fails it fails HARD. You have to rebuild them *before* they blow.
You make a good point
I spotted the problem before you took it apart. It's a trybilt. Lol
nailed it.
I have a TB685EC (41CDZ68C766). My fan blade broke and I have been searching the net ALL day looking for JUST the blade. It can have the pawls attached. The best I could find was an oil pan assembly for $45 on Amazon. I do not need the oil pan. All the parts diagrams I found did not single out the fan, it wasn't even mentioned as a part. Would you happen to know where I could find JUST the fan assembly?
unfortunately no, I have only be able to find the oil pan as well.
Low oil -gas spark friction time bomb
Well put
It was running hot and and the pistonring expanded too much and broke of pistontop.
With a larger ring-gap and a richer air/fuelmix this would never happened.
I do believe you are correct. Thanks for the comment I appreciate it
Mine seems like it has too much compression. The cord will pull great without the spark plug but is too hard with spark plug in. What should I check. It was given to me so ...
Check the valve lash. It seems to be out of adjustment.
That was happening on my echo srm210, I discovered that the fuel line had a small split in it where it goes into the grommet, when I would prime it my guess is that it wasn't getting sufficient fuel and not lubricating the engine, I used to have to take the spark plug out and spin the engine over replace the spark plug and then it would pull easy and start right up, it baffled me until one day I noticed fuel seeping out of the grommet area and discovered the cracked fuel line, once I replaced it I never had the problem again, now it pulls easy like it should, I almost broke my wrist a couple of times when it snapped back on me, I hope this helps. On eBay you can purchase an entire tune up kit that includes the fuel lines with the grommet, a new spark plug and air filter real cheap.
I've seen this on turbo charged cars. the engine definitely prematurely detonated and caused a crack in the piston. which then splintered off. eek.
I think you're right .
Wow that's very unfortunate that the piston is destroyed that's why despite the cause of it we should take good care of any engine we ever own otherwise we're gonna be paying big fees on new ones...
agreed
you never changed the oil , thats what wrecked the engine DAHHH
Theres only about an hour on this oil since it was last changed.
I bought the modelTB590 EC a couple of years ago followed proper break in procedure changed the oil and 15 minutes in to using the roto tiller attachment on a small flower garden (which was tilled and added compost as well as lots of vermiculite for aeration the previous year) the engine seized without warning. Troy built replaced it under warranty. I asked the technician that worked on it what the cause was. He told me the top end of the engine hardly gets any lubrication when not tilted side to side regularly. Now I roll the replacement 200-360° every minute or so even when just trimming. I haven't had a problem with it since someone that doesn't work for troy built told me had to be done in order to have the engine not self destruct from using it the same as any 2 stroke trimmer.
Randy9633 360?? Does not get oil in the cylinder? Guess not if you just spin it. Interesting. I have been concerned with using a 4 stroke at different angles for too long.
I will definitely keep this in mind.
i have the same model but ithink its the start rope something inside it
Yes the pull rope start system is prone to breaking on this model
The pawls broke on mine.
@@MrTaylorfenoglio Cluth or something like that broke in mine?
Ciao ma una bella pulita al cilindro è una lucidata con le spazzole che hai pistone nuovo.. dici che ne varrebbe la pena?
non ne vale la pena
Agreed. This is why I hate 4-cycle weedeaters or blowers. I have owned one of these and it just broke after a year, now Would not start. They are so difficult to maintain. The problem is that the weedeater was made in China, which is why they were meant to break in no time anyways. Troy bilt thinks they never let people down, which is absolutely not true. I have used a vintage Montgomery ward tiller (40 years old) without an issue, and STIHL equipment with no issues whatsoever. Ethanol is another thing that kills weed eaters whether 2-stroke or 4-stroke. Not only that, these new engines (even the MTD-clone engines, including craftsman, etc) nowadays are pure China junk, whether 2-cycle or 4-cycle. My mom had a MTD riding mower from 1991 and it works after years of use. Research WeedEater GTI15T running in 2018, these old engines were the best back in the old days, made in USA. So much for Built for life.
4 cycle weedeaters definitely have some issues. Thanks for the comment I appreciate it
My uncle has a John Deere model 430 (diesel, 30+ years old) and had never had major trouble with it.
@@JoshuaAndMom definitely a well built machine
I’ll stick with my 2 cycle equipment as long as possible. Only 3 moving parts and a continuous supply of fresh oil. They usually last between 12-15 years if I buy a good quality unit. I cheaped out and bought one of these a few years ago. NEVER AGAIN!
I'm right with you Andy Becker
INSIDE HOUSE GARAGE MTD= Minutes Till Destroyed.
@@andybecker2693 nice acronym
Well I’m watching it after
where does the three lines going to the bubble go to
I don't have this trimmer anymore so I can't answer that.
With oil that black tells me it was never changed or not changed enough. Plus these motors are not meant to used at full throttle 24/7. So to me it's a little of both...dirty oil + engine too hot.
Thanks makes sense
How do you call that black fan we’re the pull start is
Not sure what it's called but it can be bought as an assembly worth the oil pan.
the rope is not start in the engine when i pull it why?
check the fuel first and make sure its fresh after that confirm that you have spark.
I was surprised to see a fan for the engine. I guess they used a pore quality piston. I’ve never seen that happen to a engine. Do you know how expensive the trimmer is new?
If I had to guess over $220.
My TB685EC was 199.
I bought a 4 cycle yard works trimmer. I used it a couple of times and I left it in working condition last week. This week when I tried to start it white smoke comes out from the carburetor when I pull the string. I didn’t start it fearing that it might damage it more. What would be causing this?
How was it sitting while it was being stored?
@@INSIDEHOUSEGARAGE it was lying down with the carburetor and spark plug upside
@@manpreet9766 you mean laying level on the ground or a shelf? are you turning the trimmer sideways to edge too?
@@INSIDEHOUSEGARAGE laying level on the ground. I am not sure if I laid it on side ever.
I wish someone would explain how the oiling system on these engines works, oil pump, splash, or what, and how can they oil when turned upside down? I can't find anything online about these oiling systems, I guess it's a secret
It looks to be splash oiling as the connecting rod has a dipper on it.
@@INSIDEHOUSEGARAGE I did not see the dipper on the rod, but it is hard to see how it can get properly lubed, as string trimmers get turned upside down and all other positions while running wide open, my 40 year old Kohler has splash oil system and never lets me down, but I run it right side up thanx for the reply good vid
@@bowlweevil4161 thank you for the comment I appreciate it
Got the same issue with piston broken on sides. I bought the same trimmer again for cheap due to all attachments that I have already so most likely will happen in the future. O well really poor material design.
you got that right Left Lane.
The designer of this unit came from the auto industry. These guys design to build without thinking about repairing them. That's one reason everything is throwaway. I hate that. Thank goodness for small engine repair private guys that don't charge an arm and a leg to fix something.
Very true. Thanks for the comment I appreciate it
What happen to it is Troy built it.....cause mines just stop working on me. It was running well then just stopped, cut off and now has no compression...
That's what happened to this one. Thanks for the comment I appreciate it
Mine too. Never buying Troy bilt anything again. Junk. Gonna get a stihl next time
@@kylekindle8225 Check out the Echo's, they do pretty well.
Actually, this Troy Bilt is made by MTD. They make Craftsman and Cub Cadet, along with many others.
Too much RPM's when Engine is cold. Let it warm up!
Thank you for the comment I appreciate it
agree, i've seen the same on two strokes.
That broken cylinder makes me think that if you plan to run this one for a while you might want to add oil to the gas anyway as that is the place where you'd expect an overheat to break. Of course it could be cheap metal too but that's the Chinese model -- make it real good for the first couple of year models until you get good word of mouth, then cheapen everything and let the market run its course. That's their profitability model and it has worked in the past. Of course, there's no real future in it but they don't care about that -- make as much money as you can for a few years and then get out while the gettings good.
You know, that makes some sense.
Cant you just change the piston and head to brand new and be using it again ?.
Yes it could but this trimmer is way to heavy so I want to replace it with a lighter 2cycle.
that oil has probably never been changed. it's obvious that the most likely cause of it's destruction was that too many metal particles came off in the oil resulting in the oil raising it's running temperature way too high, until the point where it eventually started going into the piston rings & deforming the head, or the heat from the oil caused the piston to melt
nope, I changed the oil before I sold it, Turns out they were using on its side even though they were told not too. The oiling system doesn't work in that position
@@INSIDEHOUSEGARAGE ah, i see. my bad for being wrong. thanks for clarifying the issue👍
So now you need a piston a rings and can you fix the scored block?
oh no, it's too far gone,
@@INSIDEHOUSEGARAGE Thanks for the reply so the only thing you could do is get a parts donor for cheap. Be well my friend
Did you run it out of gas or low on gas at wide open throttle?
no
Possibly you have used ethanol fuel and not unleaded and it has overheated (cooked) the piston, but I am not an expert.
that's always a possibility, thank you 2001 cavador.
Dirty oil got that piston ! First off you only have a very small amount of oil in the crankcase just a few ounces and it has to be clean at all times! Dirty oil contains contaminates and blow by combustion particulates ! It also cannot displace heat as well as clean oil!
you are absolutely right about that.