stihl chainsaw racing after a cut

teachingscience · Sep 23, 2016

I also posted on tool talk but need advice from as many as i can get. So, I recently put a carb kit in my MS280 and a new coil. Now after a heavy cut it revs for about 10 seconds. Its dangerous and almost caused a kickback once when I pulled out of a log after a cut. I have adjusted it every way I can and not improvement. Another thing thats strange, I can screw the high jet in completely and it still runs fine except the revving. Any wisdom you can share would be appreciated.

Charlie

Ivan in Mich · Sep 23, 2016

I have a MS 290 and mine did something similar and what I found was the carb had loosened up

Russ from MN · Sep 23, 2016

My thought is the same as Ivan's, maybe a vacuum leak?

Bret4207 · Sep 24, 2016

Vaccuum leak either at the carb boot or seals. Could also be a trigger lock sticking if it has one, some carbs can be reinstalled so they are tilted one way or the other a bit. Could also be the throttle linkage is sticking.

Donald Lehman · Sep 24, 2016

I'll go along with everyone else here and say you have an air leak.

barry county · Sep 24, 2016

MS270 and MS280 saws were notorious for tearing the intake boot behind the carb, causing an air leak and making the saw run lean. If run like this very long, you will score the piston and cylinder, and will be replacing/rebuilding the saw!

Jiles · Sep 24, 2016

Your statement--- "I can screw the high jet in completely and it still runs fine except the revving." suggest you have a carb problem. In most cases, an air intake leak, will cause the saw to rev or go dead when idling.
Usually, backing the adjustment screws out, will mask the problem somewhat. Screwing the "H" screw in, cuts off gas supply. (leaner)
Your statement indicates that the carb gaskets may have been installed incorrectly, or the adjustment screws may have been switched?
On most Zama carbs, the sharp ended screw goes to the "L" position in the carb (closest to intake manifold.

stihl chainsaw racing after a cut

teachingscience

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Ivan in Mich

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Russ from MN

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Bret4207

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Donald Lehman

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barry county

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Jiles

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