Saw not revving level / revs + smokes when tilted

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zmender

Feeling the Heat
Dec 27, 2021
487
CT
Hey guys... ran into this issue, post it to the arborist forum and not getting much luck there, wondering if y'all have see this problem before. Trying to get some help diagnosing my old Rancher 55. Yesterday I was bucking + cutting up a blown over ~24in beech. All went pretty well in the morning where I got through 2 tanks of gas and cut up the trunk. I stopped for lunch, sharpened the chains a bit and resumed to cut the major limbs, that's when the saw refused to rev up when I hold down throttle. It still speeds up, but not enough to actually cut wood.

I pulled the air filter and try to block the air intake a little. First time the saw immediately sped up, second time and going forward the saw did not speed up or just dies.

I let the saw cool down and pulled the plug, it's normal looking but slightly slick, maybe running too rich? I installed a new plug + adjusted the H+L knobs, but neither had any effect on saw, idle or full throttle. That's when I discovered tilting the saw blade downward towards ground allowed the saw to rev to normal rpm (by sound) and at same there was thick blue smoke. It was bogged down when I tried to cut but at least it cut through thin limbs. As soon as I return the saw to level, it stops revving again.

I think it's a carb adjustment issue? But the knobs had absolutely no effect so idk. Was hoping to spend this weekend cutting up some ash that I scored at local wood + limb dump and hoping saw is running by that time.

There's also a lot of thick-looking bar oil being flung around occasionally. In fact a few minutes and my driveway was covered by those thick mucus-like drippings. Not sure if this means anything or not.
 
Pull the muffler and look at the piston, if it's ok then continue diagnosing...
 
Might have a cracked fuel line in the tank... BTDT...fill the fuel tank and see how it acts
 
My Husky 359, a couple of months ago, lost power and died. Before that it had been erratic, not starting and later starting just fine. Before it died It was running fine. I shut it off for a bit and If I remember right there was an unusual amount of exhaust smoke when I first got it restarted. I had to play with the throttle to keep it running just before it finally quit. I had the advantage of learning the 359 carbs had a bad reputation so went right to replacing that.

Bought a Stens replacement carb on Amazon, a little more than the $22 ones and maybe not any better but sold by a company with a name. A couple of good youtube videos and a head scratch or two it was up and running well.

The 55 rancher is a very nice all around saw. Among the things I liked about the one I had was the balance when limbing, had an 18” bar.
 
Personally i would look at the piston, then move on to a vacuum and pressure test if the piston looked good.
Then you know the health of the saw before the parts cannon comes into play