Poppet valve definitely was the overheating issue on my 99 200hp OX66. Was stuck in the open position and would overheat when idling. There was a design issue and Yamaha changed the design to prevent the sticking open.
Dude, anybody ever tell you that you sound just like Kevin James talking lol. I worked on a 1990 150ETXD for a guy that was way worse than that and was overheating and going into "limp mode". I removed the lower unit and used 2 gallons of RydLyme descaler with 2 gallons of water pumped into the water pump tube with a submersible pump and allowed it to recirculate for 2 hours with t-stats removed. Amazing results, for less than a $170 For Rydlyme, new t-stats and bypass valve the overheating problem was fixed. Nice video sir.
Just an FYI ( my $.02) The "heads" that you referred to while explaining to your son, are the CYLINDERS. You had already removed the HEAD. This operation is VERY critical and LOTS can go wrong, ESPECIALLY broken bolts. It doesn't matter, really, what you say to US when doing an instructional vid but it DOES matter when instructing your child or a friend who looks to you for knowledge or advice. Those engines are now PUSHING $20,000 AND UP NEW, so ANYTHING we can do to avoid going to the stealership is good for us but being meticulous about how we do it is the key. I don't fault anyone for trying to repair their own stuff and when/if they have to bring it to me to fix a flub, I tell or show them how to do it correctly. where some mechanics seem to revel in teaching them a lesson for DARING to try to fix their own stuff. Some of the other details are listed in the comments below so please don't take it personally. Some of us learn by doing and then others are lucky enough to learn from doers, so it's good that you take the time to show people what to expect. ....
I would never remove a gasket with a screw driver :0. I use my snappy upholstery / trim remover which is plastic. If that soft aluminum head/block gets scored by that hardened tool steel, that’s a trip to a machine shop
at slow or idle speed, I'd recommend doing the poppet valve first. you can also run the hose with the poppet valve housing removed to get and crud and sand out of your system. (a good flush) removing the heads can keep you off the water for a long long time if you shear a bolt off. Just my opinion, great work overall. I have a few videos on the poppet valve and some tricks to do it too.
Hey, i have a yamaha 200 2 stroke 2005 (not the saltwater series). Thermostats are brand new, impeller kit is brand new, power head gasket is new, but going with speed it over heats. What do you think the problem may be?
@@brett8074 have you looked into the poppet valve? we have a series of videos covering it and explaining how it works. if you notice you over heat at slower speeds I would look into that. Also are you 100% sure the impeller was put in the correct way as far as the way it spins? that's a common problem. lastly the pick up tube may have not been lined up correctly when reinstalling the lower unit. please comment back if any of it helped, if not we can keep trying
@@ReelTeaseFishing hey, I haven’t had a chance to check it as yet, what do i look for when checking the poppet valve? By the way I’m sure the lower unit and impeller was put in correctly.
@@ReelTeaseFishing i can idle all day no problem, it would never run hot, but when i push throttle and get up to good speed, after like 20..30.. seconds or maybe a minute, the heat alarm goes off, and the alarm stays on for atleast 5 to 10 mins.. i had to take engine cover off so it could cool down quicker
@@brett8074 if its only happening when you are running, It would not be the poppet valve. poppet valve issues are at idle or low speed. It seems to me that not enough water is getting to the engine, thus overheating at high RPM's. the impeller on a right hand turn engine (most common) should be installed clockwise looking down at the impeller. Counter rotating or left hand engines would be installed counter clockwise looking down at the impeller. also while inspecting this, make sure you get the pick up tube to align with the impeller housing. This would be the first thing I double check before digging into parts and spending $. I have also seen where the key (half moon) on the impeller was not installed causing it to not spin under load.
I just went out yesterday and my HPDI 250 over heated when I opened it up but not while at low idle. I thought I saw a bit of smoke coming out the exhaust but thinking back on it, I'm wondering if it was steam. I'm hoping it's the thermostat or the gasket. The entire top end was rebuilt 5 years ago but do to covid it sat for 2 to 3 years. Anyway I am hoping its a simple fix. I appreciate your video, thanks.
Good video. I to have the same engine and about to put the head and water covers back on. I didn’t see you tell the viewer the correct way the gaskets go on. Anyway you could chime back in and tell the way you put the head gasket and water jacket gasket back on, and explain why it goes on that way. On your other tear down clip you did, looked like my engine. The previous owner didn’t flush the engine at all. Tight
Hi Sir, I just did my DT225 without remove the heads, I put de scaller fluid 50/50 by leg pick up and run it for about 1 hour, and its doing a super job than just brush clean the heads. Costs $5.
That’s great that worked for u . But for someone who has a serious clog it’s like trying to use drano when u have concrete in your plumbing . Serious buildup turns into hard concrete like Substance in the passages . Descaler won’t get that out . Elbow grease , a chisel/screwdriver and some wire brushes are the only solution .
@@arnoldtrevilla True. Restrictions on internal passages, use hot 100% de-scalar, and I did 4 motors last year, all but one Honda that needed repeated cooking to open the internal paths, saved it from scrap yard.
2 stroke motors have water passages around the combustion chamber, cylinder head, exhaust covers and lower crankcase areas which sould be cleaned as well to factory delivered conditions. I know huge work removing the entire crankcase to access such parts. Once cleaned will need to install new gaskets on those mentioned parts right after all the mating surfaces has been cleaned to an immaculate state. Rydlyme, Salt Away only works well removing salt layers, but not heavy solidified stone rock crusts clogging the water passages in which these products won't recirculate through to do their homework right.
so I just rebuilt my 2.6L OX66 , same block as yours and it runs hot and will overheat over 4000 rpm , I have 80 hours on it so Its mechanicaly correct , I did paint the water jackets on the heads , im wondering if I put too many layer of paint on it . new water pump , thermostats and the updated pressure relief valve
Ok so u removed the water jackets and painted them . Ok so they are clean so that’s not where ur problem is . did u do the area behind the power pack that has a bunch of water passages as well I didn’t do. Mine but it can be a problem Here is the video th-cam.com/video/eTm3B-j34I0/w-d-xo.html
@@arnoldtrevilla yes , the powerhead was removed disassembled and pressure wash , then the machine shop washed it again before and after they bored it out , I guess I could have put a gasket on backwards or possibly got the wrong gasket from the rebuild kit
rydlyme marine descaler would have saved you a lot of time and you got lucky you didn't brake some head bolts Yamaha suggest dipping the bolts in two cycle oil before reinstalling
Hey thanks maybe the descaler would have helped this time but last time it was hard getting the caked in salt with a screw driver so sometimes you actually need to do the job. I did reinstall the bolts with Yamalube grease
Thanks for the vid!!! I just did both thermostats... and my poppit (PRV) valve. My motor, 2001 250hp ox66 SX250TURZ, also has a "thermosensor". Only ONE, on the STARBOARD side, directly next to the thermostat, I have a thermosensor sticking straight up w/ an electrical connection. Online, yamaha OEM parts lists this as a "thermosensor"... but my manual calls this an "engine cooling water temperature sensor". First off, do you do maintenance on these, cleaning or replacing? And second, what's the purpose? If the thermostats are both measuring the temperature of the water, then what is the thermosensor doing? Any insight is appreciated... thanks.
Engine Must Maintain a Running Tempurature to Be Efficient. Example: My Engine Runs Thermostat of 120° F. If You Lived in Cold Country and Water Was 30°F Engine Would NEVER Get to 120°F. Thermostat Stays SHUT until Engine Reaches Running Temp.
Hola , por favor me puede poner por aquí que torke le diste en la primera vuelta y en la segunda para la tapa de arriba y la del cilindro ? Muchas gracias 🙏
Just remember, flush the engine for at least 15 minutes with salt away. The thermostats must open to flush best you can. I favour a drum to run the motor, either way is OK.
yes they didnt look bad. but guess what, what little buildup there was when i removed it fixed the overheating problem. It certainly helped. I dont get the alarm anymore. Even a little buildup can cause it to heat up i guess when you add the summer temps and shallow water and slow speed or running at idle for a long time..
Leo my engine doesnt over heat 90 percent of the time. I still have some lingering issues at low speed over idle for extended periods of time on a hot day. Check this video out. I bet its the intake behind the power pack. Never thought of checking that . thats where the water is drawn in by the impeller to the power head. th-cam.com/video/eTm3B-j34I0/w-d-xo.html im going to do this job next.
I went to a Yamaha parts dealer in Key Largo . U can order them from any Place that sells Yamaha parts. Give them your engines serial number or model number
You are correct but none of the professionals would to y the engine bc the labor hours involved far exceeded the value of the engine . I’ve done it twice using the correct torque specifications had no issues but you are right.
***FYI*** preferred gasket removal tool/s, HARBOR FREIGHT TRIM TOOL KIT, not a aa METAL FLATHEAD screwdriver (@ 05:10 , which tends to severely scar the head or H20 jacket, etc. DUDE, FO REAL .)
folks Check out this webpage to see how to do go even further and clean behind the power pack, in the middle between the cylinders where the water comes in through. th-cam.com/video/eTm3B-j34I0/w-d-xo.html
Poppet valve definitely was the overheating issue on my 99 200hp OX66. Was stuck in the open position and would overheat when idling. There was a design issue and Yamaha changed the design to prevent the sticking open.
Dude, anybody ever tell you that you sound just like Kevin James talking lol. I worked on a 1990 150ETXD for a guy that was way worse than that and was overheating and going into "limp mode". I removed the lower unit and used 2 gallons of RydLyme descaler with 2 gallons of water pumped into the water pump tube with a submersible pump and allowed it to recirculate for 2 hours with t-stats removed. Amazing results, for less than a $170 For Rydlyme, new t-stats and bypass valve the overheating problem was fixed. Nice video sir.
Just an FYI ( my $.02) The "heads" that you referred to while explaining to your son, are the CYLINDERS. You had already removed the HEAD. This operation is VERY critical and LOTS can go wrong, ESPECIALLY broken bolts. It doesn't matter, really, what you say to US when doing an instructional vid but it DOES matter when instructing your child or a friend who looks to you for knowledge or advice. Those engines are now PUSHING $20,000 AND UP NEW, so ANYTHING we can do to avoid going to the stealership is good for us but being meticulous about how we do it is the key. I don't fault anyone for trying to repair their own stuff and when/if they have to bring it to me to fix a flub, I tell or show them how to do it correctly. where some mechanics seem to revel in teaching them a lesson for DARING to try to fix their own stuff. Some of the other details are listed in the comments below so please don't take it personally. Some of us learn by doing and then others are lucky enough to learn from doers, so it's good that you take the time to show people what to expect. ....
I would never remove a gasket with a screw driver :0. I use my snappy upholstery / trim remover which is plastic. If that soft aluminum head/block gets scored by that hardened tool steel, that’s a trip to a machine shop
at slow or idle speed, I'd recommend doing the poppet valve first. you can also run the hose with the poppet valve housing removed to get and crud and sand out of your system. (a good flush) removing the heads can keep you off the water for a long long time if you shear a bolt off. Just my opinion, great work overall. I have a few videos on the poppet valve and some tricks to do it too.
Hey, i have a yamaha 200 2 stroke 2005 (not the saltwater series). Thermostats are brand new, impeller kit is brand new, power head gasket is new, but going with speed it over heats. What do you think the problem may be?
@@brett8074 have you looked into the poppet valve? we have a series of videos covering it and explaining how it works. if you notice you over heat at slower speeds I would look into that.
Also are you 100% sure the impeller was put in the correct way as far as the way it spins? that's a common problem. lastly the pick up tube may have not been lined up correctly when reinstalling the lower unit. please comment back if any of it helped, if not we can keep trying
@@ReelTeaseFishing hey, I haven’t had a chance to check it as yet, what do i look for when checking the poppet valve? By the way I’m sure the lower unit and impeller was put in correctly.
@@ReelTeaseFishing i can idle all day no problem, it would never run hot, but when i push throttle and get up to good speed, after like 20..30.. seconds or maybe a minute, the heat alarm goes off, and the alarm stays on for atleast 5 to 10 mins.. i had to take engine cover off so it could cool down quicker
@@brett8074 if its only happening when you are running, It would not be the poppet valve. poppet valve issues are at idle or low speed.
It seems to me that not enough water is getting to the engine, thus overheating at high RPM's.
the impeller on a right hand turn engine (most common) should be installed clockwise looking down at the impeller. Counter rotating or left hand engines would be installed counter clockwise looking down at the impeller.
also while inspecting this, make sure you get the pick up tube to align with the impeller housing.
This would be the first thing I double check before digging into parts and spending $. I have also seen where the key (half moon) on the impeller was not installed causing it to not spin under load.
I just went out yesterday and my HPDI 250 over heated when I opened it up but not while at low idle. I thought I saw a bit of smoke coming out the exhaust but thinking back on it, I'm wondering if it was steam. I'm hoping it's the thermostat or the gasket. The entire top end was rebuilt 5 years ago but do to covid it sat for 2 to 3 years. Anyway I am hoping its a simple fix. I appreciate your video, thanks.
Good video. I to have the same engine and about to put the head and water covers back on. I didn’t see you tell the viewer the correct way the gaskets go on. Anyway you could chime back in and tell the way you put the head gasket and water jacket gasket back on, and explain why it goes on that way.
On your other tear down clip you did, looked like my engine. The previous owner didn’t flush the engine at all. Tight
Hi Sir, I just did my DT225 without remove the heads, I put de scaller fluid 50/50 by leg pick up and run it for about 1 hour, and its doing a super job than just brush clean the heads. Costs $5.
That’s great that worked for u . But for someone who has a serious clog it’s like trying to use drano when u have concrete in your plumbing . Serious buildup turns into hard concrete like Substance in the passages . Descaler won’t get that out . Elbow grease , a chisel/screwdriver and some wire brushes are the only solution .
@@arnoldtrevilla True. Restrictions on internal passages, use hot 100% de-scalar, and I did 4 motors last year, all but one Honda that needed repeated cooking to open the internal paths, saved it from scrap yard.
@@arnoldtrevilla This fluid is outboard safe. It will not eat alum.
Leg pick up is the pipe after impeller, so leg needs to be removed.
Involved Your Kids in Mechanic's, Good Video
dude you kick ass! this is awesome very informational. fixed my over heating issues
2 stroke motors have water passages around the combustion chamber, cylinder head, exhaust covers and lower crankcase areas which sould be cleaned as well to factory delivered conditions. I know huge work removing the entire crankcase to access such parts. Once cleaned will need to install new gaskets on those mentioned parts right after all the mating surfaces has been cleaned to an immaculate state. Rydlyme, Salt Away only works well removing salt layers, but not heavy solidified stone rock crusts clogging the water passages in which these products won't recirculate through to do their homework right.
100 percent
@08:50, use a media blaster, w/pecan or walnut husks ,depending on severity of the head, corrosion, etc.
You engine vro is running lean on oil which can cause overheating or faulty thermostats
Great Video, and good that you teaching your kids, so they will be saving some money and doing their own repairs
Great video THANK YOU !!!
milimeters are metric system 😊
so I just rebuilt my 2.6L OX66 , same block as yours and it runs hot and will overheat over 4000 rpm , I have 80 hours on it so Its mechanicaly correct , I did paint the water jackets on the heads , im wondering if I put too many layer of paint on it . new water pump , thermostats and the updated pressure relief valve
Ok so u removed the water jackets and painted them . Ok so they are clean so that’s not where ur problem is . did u do the area behind the power pack that has a bunch of water passages as well I didn’t do. Mine but it can be a problem
Here is the video th-cam.com/video/eTm3B-j34I0/w-d-xo.html
@@arnoldtrevilla yes , the powerhead was removed disassembled and pressure wash , then the machine shop washed it again before and after they bored it out , I guess I could have put a gasket on backwards or possibly got the wrong gasket from the rebuild kit
I had the same issue with overheating over 4000 rpm. The cooling system was working well. In my case it was a crack in the exhaust pushing water back.
rydlyme marine descaler would have saved you a lot of time and you got lucky you didn't brake some head bolts Yamaha suggest dipping the bolts in two cycle oil before reinstalling
Hey thanks maybe the descaler would have helped this time but last time it was hard getting the caked in salt with a screw driver so sometimes you actually need to do the job. I did reinstall the bolts with Yamalube grease
Thanks for the vid!!! I just did both thermostats... and my poppit (PRV) valve. My motor, 2001 250hp ox66 SX250TURZ, also has a "thermosensor". Only ONE, on the STARBOARD side, directly next to the thermostat, I have a thermosensor sticking straight up w/ an electrical connection. Online, yamaha OEM parts lists this as a "thermosensor"... but my manual calls this an "engine cooling water temperature sensor". First off, do you do maintenance on these, cleaning or replacing? And second, what's the purpose? If the thermostats are both measuring the temperature of the water, then what is the thermosensor doing? Any insight is appreciated... thanks.
Engine Must Maintain a Running Tempurature to Be Efficient.
Example: My Engine Runs Thermostat of 120° F.
If You Lived in Cold Country and Water Was 30°F Engine Would NEVER Get to 120°F.
Thermostat Stays SHUT until Engine Reaches Running Temp.
Hello good day. I did not hear you say if you solved the problem, greetings.
Yes that solved it no more overheating
@@arnoldtrevilla nice
@@arnoldtrevilla nice
Your water passages have restrictions, removing heads may solve the issues.
Yes that’s what I did
$180 is expensive? Have you priced out a new Yamaha 200?
Great video boys!!
Hola , por favor me puede poner por aquí que torke le diste en la primera vuelta y en la segunda para la tapa de arriba y la del cilindro ? Muchas gracias 🙏
Esta eacrito en el motor en la covierta de los cylinder heads
@@arnoldtrevilla si lo vi muchas gracias 🙏 pero el primer pase a cuanto mas o menos ? Disculpa la molestia 😅
@@micheloquendo5528 it’s in the video . It says 11 lbs first then 22 lbs second time but watch the video and it says it there for this engine
****PUT THE BOLTS BACK IN PLACE BEFORE CLEANING @ 08:20 time in the video (to prevent thread issues later !
Just remember, flush the engine for at least 15 minutes with salt away. The thermostats must open to flush best you can. I favour a drum to run the motor, either way is OK.
I mean may not. I have a few descaller videos showing a true water passage cleanings.....
Hi does your ox66 run rough around 5 to 6 mph ? If so why? Any other speed or idle is perfect
Hi no it runs great. Sounds like u may have to redo your carbs
Great dad move.
You aren’t supposed to start the engine while hooked to the flush port.
Asid flush with foot off i would of done pop out thermostats out put caps back on
Was that your problem? Water jackets didn’t look bad.
yes they didnt look bad. but guess what, what little buildup there was when i removed it fixed the overheating problem. It certainly helped. I dont get the alarm anymore. Even a little buildup can cause it to heat up i guess when you add the summer temps and shallow water and slow speed or running at idle for a long time..
Leo my engine doesnt over heat 90 percent of the time. I still have some lingering issues at low speed over idle for extended periods of time on a hot day. Check this video out. I bet its the intake behind the power pack. Never thought of checking that . thats where the water is drawn in by the impeller to the power head. th-cam.com/video/eTm3B-j34I0/w-d-xo.html im going to do this job next.
@@arnoldtrevilla Run descaler fluid through water pick while run the motor, will do a much better job than take parts offs.....
Where do I order these gaskets
I went to a Yamaha parts dealer in Key Largo . U can order them from any Place that sells Yamaha parts. Give them your engines serial number or model number
2 words- MURATIC ACID. tape all mating surfaces before applying. Dip in soapy water to neutralize.
Asking for real trouble taking off the heads unless you are a professional
You are correct but none of the professionals would to y the engine bc the labor hours involved far exceeded the value of the engine . I’ve done it twice using the correct torque specifications had no issues but you are right.
***FYI*** preferred gasket removal tool/s, HARBOR FREIGHT TRIM TOOL KIT, not a aa METAL FLATHEAD screwdriver (@ 05:10 , which tends to severely scar the head or H20 jacket, etc. DUDE, FO REAL .)
Agree, Crude Tool
Putty Knife lay flat better Choice.
I would change the poppet valve
Hi
No todos hablamos inglés
💓👏👏
COCINA CON JISA thank you
folks Check out this webpage to see how to do go even further and clean behind the power pack, in the middle between the cylinders where the water comes in through. th-cam.com/video/eTm3B-j34I0/w-d-xo.html