carb issue

[madstone]

I have a ms 390 that has a muffler Mod I have a run abilty issue with the saw I adjusted the low end so the saw finnally idles and adjusted the high end so the saw runs out good at high idle. with a plug check after a full tank of fuel ran through it shows a reading of tannish white brown. my promblem is, is when i let off the throttle the saw countinues to run at full throttle for 10-15 secs and then idles down to run normal. it also is extremly hard to start when cold. any help on this would be greatly appreciated cause it has me stumped.

 

[1steve]

Make sure your linkage isn't binding, try richening the L needle and see if it improves. Or you have an air leak and need to pressure/vacuum test. Post your findings.

 

[madstone]

well i tried the above mentioned suggestions and to no avail the saw just wont run right so in addition to the suggestions i rebuilt the entire carb this afternoon including needk
le and seat. Saw still doesn't run right so it is now on vacation at the sthil dealer where it will be air tested with some sort of pressure system and also i have abrand new carb coming for it. i couldn't beat the price for 30.00$. Thanks for the info and i'll let you know how it runs when I get it back.

 

[1steve]

Sorry you didn't get it fixed, hope it turns out not to be much wrong. Keep us posted.