290

[sbvfd592]

well got a 290 with a scored piston not to bad damaged but it will only run for a min or so but only when i have the muffiler off,the screen is clean and all do your think there is to much back pressuer??? I will check my compesion rate tomaro I hope i dont have to take the hole thing apart to replace the pistion can it just me a carb ajust it runs ok when the muffiler is off loud as hell lol i need help

 

[stihltech]

Is the compression OK/ Can you pick it up by the starter handle and the rope will stay in or come out very slowly? We have to get some basics here first.

 

[sbvfd592]

yes compresion is good it will run just not when the muffiler is on

 

[stihltech]

exhaust

Unless the muffler is actually plugged up, it should not make that much difference. A scored up piston is going to cause more problems. The internals have to be right before you can blame anything else. The other thing I check for is a good spin when you pull the cord.
Without looking, I would guess you will have to go inside before you will run correctly.

 

[Crofter]

What scored the piston? Is that cause still present. If the carb has been readjusted to try to compensate for a possible leaking crank seal etc., you could have some weird happenings. Stihltechs advice! check the basics.

 

[jokers]

With what it is going to cost you to fix that saw, maybe you should consider Jonsered`s "Bag it and Drag it" deal. You could trade that thing in for $100-$150 on a new Jonny.

I say this because if your piston is scored, what makes you think the cylinder isn`t? Have you priced a topend kit for this model? What else is wrong with this saw that caused the piston scoring?

Another thing. When you say that it runs ok when the muffler is off, have you actually put it in the cut this way or are you simply revving it and it seems ok? Most of the time you can get a saw with marginal compresion to start and run but it will fall down in the cut. That might continue to be an issue even if you replaced the piston.

Russ

 

[sbvfd592]

well i have 80 pis on saw i can get it to start with the muffiler on and all but then it will cut out

 

[Lawn Masters]

80 is too low, should be a minimum of 110 for a saw in that size class.