What is wrong with my chainsaw?

[Poindexter]

I am running a 2007 Husky 345e. 16" bar, probably 100 cords on it starting with standing timber.

No chain issues, no bar issues, no oiling issues. I have not run any ethanol/ oxygenated fuel through it since 2009. Saw has enjoyed a steady diet of Chevron 90 octane (no gasohol in Alaska) with techroline since 2009, and has ever only tasted Husky 2 cycle oil lifetime.

It starts and idles just fine. When I rev it under no load it will spin right up and scream like it was new.

Air filter and spark plug are immaculate.

When I try to cut with it, it bogs and stalls.

I am thinking carb, but it could be piston rings. There is an idle fuel circuit and a main fuel circuit in the carb. It could be that I can get to the rpm redline on the idle circuit with no load, but when I need the main fuel circuit to get to the redline under load I got nothing.

Performance fell off a cliff. One day it was running fine when I shut it down, a few months later I started it up and it was a turd.

I can get a new carb for $19, but my time is very expensive.

Should I try a new carb, or just ditch and buy new? If it is piston rings my local shop can sell me a new saw cheaper than servicing what I have.

Thanks in advance.

 

[Diabel]

No expert here. Symptoms you describe are bang on to what my little stihl exhibited some time ago. I was told to start with replacing the fuel line (cheap and easy). It fixed the problem.

 

[Sean McGillicuddy]

New fuel lines and some Seafoam should work wonders ..

 

[Corey]

I'd definitely look at the fuel line. About every 10 years, my similar vintage H 350 will make a crack in the fuel line leading out of the tank and up to the carb. At least with my saw, the tank/handle stays 'still' while the motor/carb is free to vibrate. The fuel line just pokes through a hole in the tank creating a stress point. Ultimately the fuel line gets hard and cracks, then the carb starts sucking in air / leaning out and bogging under load just like you say.

Also, depending on your meaning of 'immaculate', you might look to richen the mix just a bit. A perfectly white plug is probably a bit on the lean side and it should have at least a bit of color, though obviously not carbon build up.

 

[weee123]

Like everyone says I’d start with fuel lines, then I’d pop the carb off and make sure it’s not gummed up in there. It definitely sounds like you’re running lean. How often do you tune the saw? Should be at least once a season with the changing weather as that does affect how it will run.

 

[Ashful]

Because I'm more willing to waste an hour on a Tuesday evening than a minute of Saturday daylight, I'd just order a new carb AND a new fuel line. All under $25, and once swapped you won't spend next weekend wishing you were out sawing... unless it is the rings.

 

[EbS-P]

Have you adjusted the carb? Get a tachometer. You can do it by ear but 16k sounded good to me on my 40cc saw.

 

[salecker]

Fuel filter,clean carb.
Don't buy a chinese carb and expect it to cure it,they are a gamble
Check you muffler screen as well
If you can't fix it and don't want to pay dealer prices i am not far from you, and i would either look at it for you or if you replace it i would be interested in it.

 

[Nealm66]

I hear you on the time being valuable. I’d drop it off and let a pro tell me if it’s worth fixing, see if they will sell it on consignment and grab a new whiz bang model off the shelf

 

[ericm979]

I am thinking carb, but it could be piston rings. There is an idle fuel circuit and a main fuel circuit in the carb. It could be that I can get to the rpm redline on the idle circuit with no load, but when I need the main fuel circuit to get to the redline under load I got nothing.

A fuel flow problem would cause your symtoms. I'd start with a new fuel filter. They get clogged after a while. In my experience when gas lines fail the engine does not start. A fuel flow restriction would make the carb run low on fuel when it's working in the cut but not for a few seconds of free revving.

Another possible cause is a clogged spark arrestor screen. I take them out and burn them clean with a torch. Doesn't take much. Usually when it's the screen the engine does not want to rev out no matter if it's under load or not. So this is less likely to be the problem but it's easy to do.

Low compression in usually causes hard starting but it still runs, unless the compression is really low like there was a partial seizure and then it won't run at all. I do not think that's the problem here.