If the cam & rocker arm pins could be screwed in, that would most likely solve the problem of the pins being too loose & wobbly. A metal plate could be attached to the the plastic cam lobe, but first you would need to shave down the lobe some to keep the correct profile and height for proper valve lift.
Have had one for 14 years and never had any problems with it. Can’t beat stuff up and expect it to not to effect it have to respect your equipment and it will liv long time.
I have a FS90R that i have replaced the cam gear in, resealed the bottom end and cam cover, new carb, fuel lines, fuel filter, spark plug...you name it ive done it It still will not rev up at all, itll crank and idle for a min then die like its running out of fuel. The only thing i know thats wrong is the tank vent is cracked...but that shouldnt cause it to not rev at all should it? Any help would be much appreciated sir Love your videos
Thank you for this video! These things are getting made cheaper and cheaper, but they're advertising would have you thinking they're being made better than ever!!!
Great video as always mm1 I have a Km131r. A ht103 Br800 5hours or less on these love the Stihl 4 mix engines only run motomix fuel in them Learned a lot about the 4 mix from you thanks
great video. the Honda gx25/35 also runs a plastic cam in a legit 4 cycle, but doesnt seem to suffer the same fate as often. Perhaps just less in circulation?
Cam shaft gear very high/expensive , i don't own a mix 4 . Never worked on a 4 before or even seen one before this video . I own a regular Stihl two cycle for almost 20 years with with a primer replacement only in all those years of service .
Got any idea how many hours those stihl weed wacker 4 mix last before the cam / valve train issues? Seems like this area is so problematic on 4 mix trimmers.
Properly taken care of they will last indefinitely. People take the guards off and let more line out which in turn lowers the engine Rpm thus overheating the engine. For every inch of line past stock length adds 20° more heat. Heat is your enemy. Run the snot out of it. Get those rpms up around 10k
You had already ran the engine when I joined the live stream. I have a kombi 110 power head thats about 9 or 10 years old should I replace the cam shaft or wait till it acts up?
Thank you sir. That absolutely helps out. I'm pretty new to working on small engines, and I love all the help you provide us.
If the cam & rocker arm pins could be screwed in, that would most likely solve the problem of the pins being too loose & wobbly. A metal plate could be attached to the the plastic cam lobe, but first you would need to shave down the lobe some to keep the correct profile and height for proper valve lift.
Have had one for 14 years and never had any problems with it. Can’t beat stuff up and expect it to not to effect it have to respect your equipment and it will liv long time.
I have a FS90R that i have replaced the cam gear in, resealed the bottom end and cam cover, new carb, fuel lines, fuel filter, spark plug...you name it ive done it
It still will not rev up at all, itll crank and idle for a min then die like its running out of fuel.
The only thing i know thats wrong is the tank vent is cracked...but that shouldnt cause it to not rev at all should it?
Any help would be much appreciated sir
Love your videos
Thank you for this video! These things are getting made cheaper and cheaper, but they're advertising would have you thinking they're being made better than ever!!!
I wish id watched that last night, just adjusted the valves and that could be the reason why. Great video.
Great video as always mm1 I have a Km131r. A ht103 Br800 5hours or less on these love the Stihl 4 mix engines only run motomix fuel in them Learned a lot about the 4 mix from you thanks
great video. the Honda gx25/35 also runs a plastic cam in a legit 4 cycle, but doesnt seem to suffer the same fate as often. Perhaps just less in circulation?
MM1 do you have a video showing how to time the cam when installing a new one.I watch all your videos,have a great day.
Awesome info. Keep it coming.
What is the procedure for replacing? Does piston have to be at tdc?
Cam shaft gear very high/expensive , i don't own a mix 4 . Never worked on a 4 before or even seen one before this video . I own a regular Stihl two cycle for almost 20 years with with a primer replacement only in all those years of service .
Did you replace the crank seal also?
Thank you for Sharing, would the difference in movement of the rocker arms and valves with a good & worn-out cam wheel be easily noticeable?
I wonder if it’s a good idea to lubricate the cam with some type of lubricant?
I love live repairs
Wow! Great diagnostics. I can't understand why a company like Stihl would place a crummy piece of plastic into one of these machines though.
Got any idea how many hours those stihl weed wacker 4 mix last before the cam / valve train issues? Seems like this area is so problematic on 4 mix trimmers.
Properly taken care of they will last indefinitely. People take the guards off and let more line out which in turn lowers the engine Rpm thus overheating the engine. For every inch of line past stock length adds 20° more heat. Heat is your enemy. Run the snot out of it. Get those rpms up around 10k
You had already ran the engine when I joined the live stream. I have a kombi 110 power head thats about 9 or 10 years old should I replace the cam shaft or wait till it acts up?
A little off topic but what is a good compression reading on a Stihl 4 mix trimmer when everything is functioning properly? Thanks
A compression test isn’t a viable test because of the compression release on the cam gear the best option is to do a cylinder leak down test
Never seen a camshaft in one before
I’m sorry that you don’t believe me? I’ve got video proof right here
@@THEMOWERMEDIC1 it’s not that I didn’t believe you I’ve never seen one before
Does this issue go for all stihl weedeaters
Good video
Interesting..
Mowermedic,,,,Can u do a vacum test on a 4 stroke stihl trimmer,,,,,like u can on a 2 stroke?????,,,,,Thanks
Absolutely. Same procedure. Only difference is you need to to a cylinder leakdown test first to make sure the valves are sealing correctly
@@THEMOWERMEDIC1 Thank you....Maybe u can do a video 1 day ,,,,,never seen 1 on youtube,,,,,,Thanks again
Great info...
Need to show how to put it back together with proper timing
Soon as parts get here i sure will!!
What a great advert for not buying one. Great video though.
Looks like the muffler exit is almost smashed shut mabe it was making it way warmer than it should be
Hey is it raining over there where you're at
@@jessemartinez6601 not right now
I guess they’re plastic because they are sacrificial. it’s cheaper to replace a plastic gear than to replace metal rocker arms and gear.
The inside looks dirty , like not enough oil changes where done . Just going by what I see .