Jonsered 920 questions, low on power, chain turns constantly

[DodgyNomad]

I just bought a Jonsered 920 locally with a 24 inch bar. Good shape, 156 psi, starts easy and runs good. I'm new to this saw, and am mechanical, but haven't had to play with saw clutching or carbs much in the past. Since posting this an hour ago I turned down the idle, and tore apart and cleaned the drum, clutch and bearing, greased the bearing and reassembled, and the chain is now stationary at idle, so that problem is addressed.

Now the power issue: the saw starts and runs fine and revs nice without a load. But as soon as you start cutting and put a load on it, it has very little power and stumbles, etc.. with very little power to cut. Carb had been rebuilt 2 years ago, and the saw was rarely used since.

Any help on this saw will be appreciated. I'll be checking and cleaning the muffler, and likely adjusting the carb to try to get the power up.

 

[nmurph]

Check the fuel/vent/impulse (if it has one) lines. I would just about bet the house you have a hole in the fuel line.

 

[albert]

After you go over your fuel hose and filter, try setting the High mixture screw richer like 1.5 turns out from lightly seated and try it in a cut. That should be too rich, then keep leaning the H screw a little 1/16 turn at a time and retesting. Do a search on tuning. Lots of info to read. If the saw sat with fuel in it for more than 4-6 months, you may have to clean the carb.

 

[lpmfg]

I just bought a Jonsered 920 locally with a 24 inch bar. Good shape, 156 psi, starts easy and runs good. I'm new to this saw, and am mechanical, but haven't had to play with saw clutching or carbs much in the past. Since posting this an hour ago I turned down the idle, and tore apart and cleaned the drum, clutch and bearing, greased the bearing and reassembled, and the chain is now stationary at idle, so that problem is addressed.

Now the power issue: the saw starts and runs fine and revs nice without a load. But as soon as you start cutting and put a load on it, it has very little power and stumbles, etc.. with very little power to cut. Carb had been rebuilt 2 years ago, and the saw was rarely used since.

Any help on this saw will be appreciated. I'll be checking and cleaning the muffler, and likely adjusting the carb to try to get the power up.

That a pretty long time for a saw that hasnt been used much, it may need to be rebuilt. the carb is really easy to get to on that saw, I would consider rebuilding it real quick, also it sounds as though there is a air leak, normally if you lose power with a load you are sucking in air. Either way you want to fix the problem or take it to someone who can, screwing with stuff when you have no idea what your doing will burn up that saw and 920 P&C's arent easy to come by.. Im not trying to be rude or anything but I see it all the time where people come in and say "the saw ran great last year, now it wont run. I messed around with the carb and couldn't fix it" then they get a call with a quote for a rebuilt motor..