036 cannot idle down

[Dadatwins]

Looking for suggestions besides scrap it. Have a used 036 with 100lbs compression. Saw starts and runs but will not accept a low carb adjustment. When its started 2 pulls it revs high end smooth. As soon as trigger released to idle down saws comes down and dies. takes a second or two for it to come down after trigger release. Tried adjusting low end to compensate but same result. Even tried keeping idle screw up but just keeps saw reved up. Changed fuel line and filter, dismantled and cleaned carb. Cleaned fuel tank filter. Checked carb boot no cracks or splits. Even tried a different carb from a saw that runs fine and same result. Any ideas

 

[ccicora]

Can you vacume test the saw?? Check the base gasket and the seal behind the fly wheel for leeks.
Good luck,
Chris

 

[Dadatwins]

Tried the carb cleaner around boot no changes. Took good carb from running 036 and tried it on this one no change either. Took original carb from bad saw and tried it on good saw runs fine. Think I ruled out carb. and boot. Do not have vacum test but I think that is what wrong. Confusing me is that saw runs fine on high end smooth no breakup at all but dies when it comes down. Never had one with a blown seal act like this they usually DOA pretty quick.

 

[G-MAN]

100lbs. isn't enough compresion for that saw. should be around 140lbs.

 

[Crofter]

If you have tried another carb that is ok and didnt eliminate it, I think you will find an air leak. Spraying as rocky suggests should find leaks around boot, cylinder base or crancase joints, but I think you may find the air leak is at one of the crankcase seals as stihlman suggests. Pressure and vacumn test the crankcase.

Frank

 

[Lawn Masters]

100LBS is rather low compression for a Stihl of that size, I think you need to get some new piston rings, shouldnt be more than a $10 job to get them and install the rings yourself, its easy to do. I do it every now and then on a saw that I'm working on, no big thing to repair/replace on a saw. How old is your 036?

 

[Crofter]

Dadatwins. You can compensate for the leak at high speed because it is then a low percentage of overall air flow into saw. At low rpm the leake is more influence because it reduces the airflow past the throttle plate and low speed jet. You cant get fuel into the air that isnt even going thru the carb.

Frank

 

[Dadatwins]

Ok I got saw running and sprayed carb cleaner behind flywheel and saw dies. Blown seal right? Did it twice same result.
Never had one hang on with a bad seal this I have just seen them just die or at least cannot get smooth top end. Weird.



Tip : always make sure small hose on carb cleaner can is sprayed behind flywheel, not at it, stuff tastes nasty.

 

[Crofter]

Dadatwins; you got it. Small seal leak screws up low speed worse than high. Burst or expelled seal; its dead in the water. Make sure to change its brother at the same time.

Frank

 

[Dadatwins]

Thanks for help folks, this was a screwy one for me. Never thought about small leak thought when seal went it really went.
Thanks again. Hey RJS you said spray it first so you can take kuddos on this one

 

[xander9727]

We can't give Rocky compliments! He is bad and evil and all of his post are derogatory and inflammatory. He is the bastard step-son of Gypo Loggers love affair with a traveling gypsy. All we are to do is criticize him until he is banished.

ROCKY BAD, ROCKY BAD, ROCKY BAD......

Unless of course he's giving you good advice that you really need.
Then Rocky OK.

 

[stihltech]

compression

The compression is a little low, but with no air leaks you will probably never know it.
Give it the old pick it up by the starter handle test, if the rope stays in or comes out very slowly, you will be OK.

Looks like some people on here have listened when I talk.

 

[Dadatwins]

Compression seemed ok on this one I thought held by handle and saw did not move. Gauge read 100 -110 few pulls. Will probably swap rings while I have apart anyway. Saw really does not look that beat up at all has all paint and stickers looked taken care of. Looks can be deceiving though.

Sorry about giving RJS credit I have been inhaling carb cleaner for about an hour in the garage, it will not happen again