Chainsaw on the fritz, any Thoughts

[John K Jordan]

How long since it was last used? If it sat for months I'd dump the gas and try new gas/oil mixture. (If cleaning the air filter didn't help.) I had a Honda generator that acted like that and it turned out to be some buildup in the jet. Thing was, I could see light through the jet and it looked clean but it had some "varnish" inside from sitting unused with old gas. Cleaned the jet and it ran fine.

JKJ

[Brice Rogers]

I'd follow the previous advice first: dump the gas, put in fresh stuff, blow out the carb air filter, stick in a new plug.

Then, if it still doesn't run, something that I would do next ("low hanging fruit") is to note the position of the high speed jet (or both if you don't know which is which). Then I would tighten them, counting the number of turns (and fractions). Write it down. Then unscrew and remove them. Keep the jet screws separate (in case they are different). Then squirt in a carb cleaner like B-12 using the small tube nozzle stuck into the jet hole. Then put things back together, tighten the carb adj. screws and back them out to their original setting. That is likely to fix it.

But honestly the real problem could be a variety of different things. If that didn't work, I'd consider buying a Stihl carb rebuilding kit (they cost around $10-$15 on ebay) and also replacing the tubing and filter going into the gas tank. Sometimes the old tubing rots.

[Steve Nix]

I suggest rather than re kitting it go on eBay and but a complete new carb. I've replaced my chain saw , tiller and weed eater carbs for $25 of less.

[Bob Bergstrom]

I rebuilt a Stihl carb for a friend who was given the saw that sat for over a year. The inlet was closed with dried ethanol, had to use a drill bit turned by hand to clear it out. Ethanol leaked out the carb gasket, and both were almost like super glue. The fuel line was cracked. The inlet hose leaked, and the diagram in carb was warp and not working. All these problems were described on YouTube with how to diagnose them and procedures to follow.

[Brent Wells]

I also use Trufuel for my saw and weed eater. The 93 octane and no ethanol makes it start first pull every time. Like mentioned it has a 2 year self life when opened and a 5 year unopened. Small carbs do not like ethanol above 10% and I know stihl booklets will tell you to run at least 89 octane which will get you under 9%. If you mix your own gas they also seem to like the synthetic oil mix. Sea foam is one of the best carb/jet cleaners I have found but you may need to tear apart if fuel has started to shellac. Good luck.

[Dom Garafalo]

I've had the same symptoms with both my Stihl chain saw and Echo grass trimmer and it turned out to be a clogged spark arrester.

There's a good chance that's your problem. It is a simple fix. Take off the muffler, which will expose the spark arrester which is simply a small metal screen with very small openings which become filled with carbon. You can either toss the spark arrester or clean the screen and put it back in.

You should check to see if you have a clogged spark arrester before spending any money on other parts or small engine service. This problem is well known with shops that fix and service small 2 cycle engines.

Good luck

Dom

[Todd Mason-Darnell]

Since you can get it started, you try spray some carb cleaner into the air intake (with no filter on) will it is idling.\:

https://www.amazon.com/Gumout-800002...+cleaner+spray

(you can get this at any auto parts store)

If you have a problem with varnish build up, this may help.