394xp runs good, low cutting power

[Mastermind]

My masterminded 394 went weak in the knees in an "all of a sudden" kinda way. Randy fixed it (for free, cause that's the kinda guy he is), but I can't remember whether it was carb, or coil, or both. I can say without a doubt, that it wasn't low compression.

Coil....

Plus I tweaked in a little bit more while it was here.

 

[HuskStihl]

Coil....

Plus I tweaked in a little bit more while it was here.

Thanks again for that. No suburban homeowner should be without a 9hp chainsaw. Just in case.

 

[mifirewoodguy]

Just for reference, I bought this jug back to useable condition w/ Randys vids and advice.

Where might I find that Video by Randy?

 

[Mastermind]

http://www.arboristsite.com/community/threads/how-to-remove-aluminum-transfer-without-acid.248325/

 

[MGoBlue]

Arguably one of the most helpful videos ever!

Stem, try to post a pic like this (not my pic):

Hopefully your piston doesn't look like that one.

 

[stem]

Here are some photos of the piston from the muffler side of things. Any thoughts on the scoring? Muffler has small hole rusted through one corner, the outside/front face is a little dented, and the spark screen in the exhaust port is open on one side, but it otherwise seems functional. The white plastic intake does not seem to be cracked. I'll pull to check the underside. Thinking about getting a vacuum/pressure tester for carb. and crank seals. What do people recommend? I've been looking at the Mityvac 8500.
Sorry I'm dragging a bit on this stuff, I cracked into this during a lull, and now the phone's ringing', the chipper died (electrical/ignition/fuel pump issue), and the chip truck, that already needs and rear axle, just started acting a lot like this old 394. I will keep digging as I get more little blips of time.

-Thanks

 

[Mastermind]

In all honesty, I'd tear it down to the case, clean everything, polish the bore, and replace the piston & rings. Go back together with new fuel line, impulse line, seals, carb kit, etc.

Then you'd have a saw that would last for years.

 

[stem]

Ok, these might be better:

 

[huskihl]

In all honesty, I'd tear it down to the case, clean everything, polish the bore, and replace the piston & rings. Go back together with new fuel line, impulse line, seals, carb kit, etc.

Then you'd have a saw that would last for years.

What he said. That'll definitely cause it to lack compression.