Chainsaw Repair

I have a Jonsered 2050.  It has been running just fine for almost 20 years.  Gas is fresh, oil is Echo brand, air filter is clean, plug has only about 10 hours on it, saw is cleaned after each use, blade is sharp, etc.

However, now it has a problem after running 10 minutes or so.  The first thing I notice is it will bog down while cutting.  Then, it will not run at all at wide open throttle.  If I back the throttle off to about 3/4 I van get it to finish the cut.  If I use it the next day, it will have the same symptoms after a while.

I would rather not take it to the shop if I can fix it myself.  Any ideas?

Dave_NH

After checking above.

It might still be a stiff diaphragm from age or ethanol.   Carb repair kit $8-$15 and 30mins to do.  Just a diaphragm kit $3-$7

What color is the spark plug electrode?

No not really. A good running saw should still produce the usual tan color.

My question was along the line that the OP might have an air leak.

Next thing I would look at is the throttle cable, and make sure that the throttle plate is fully closing when the trigger is released.

Ignition module may be breaking down when heated up.