Trouble with an old Stihl 038.

[Jay]

My main medium sized saw is the 038, albeit getting a bit long in the tooth. Just for the heck of it I recently modified the muffler, and it is running strong, except that unless I have the idle screw turned to the point where the chain is turning, the saw will eventually die from too slow an idle I have noticed this tendency in a lot of older saws. I've fiddled with the low speed screw, but at a tuning where the saw accelerates well, the problem remains. I haven't pulled the carb yet, but I'm thinking it could possibly be a stiff diaphragm? Any thoughts about the problem are appreciated. Thanks in advance.

 

[Al57]

Well,you most likely hogged out the muffler so big you don't have enough back pressure to idle correctly.

You should be able to richen it up at idle to stay running but it will "load" it up so the acceleration might be sluggish.

Now the fix.Close up the holes in the muffler a tad bit or get another muffler front.E-Bay!!!!

 

[Jay]

Thanks. It's a straight shot out the muffler now, with a 3/4" hole, not much back pressure. I can stick the loose baffle back into the muffler, see if it helps.