Stihl 390 help

[BP021]

I've got a 390 w/modified muffler. Last night while cutting into red oak I noticed a few sparks & thought it odd since it was new chain. When I seen them fly again I realized they came from the muffler. I immediately shut the saw down & took a look at the spark arrestor & it was clean. Well, the saw didn't want to start back up. I took a look at it today & did get it to start, but only in warm start & will only run if I keep on the throttle, it will not idle. I also noticed an excess fuel mixture leak that seem to leak worse after running. This engine only has 6 tanks of fuel ran thru it, 93 octane & HP Synthetic. Seals?

 

[discounthunter]

pull the muffler off and take a look.

 

[AKDoug]

The purpose of the screen on the muffler is to catch those "sparks" of hot carbon. You just had the right lighting to see them. I doubt very much the are indicative of a problem with your saw. I'd remove the muffler and look for sure.


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[Ymountainman]

I have a 390

My ms 390 shoots sparks out right before dark. It is muffler modded with the screen. It runs fine.

 

[BP021]

Think I've got it fig'd out. Had to tinker w/carb & adjustments. It was definitely weird. Saw was running great then that happened. Maybe I bumped the saw while cutting down that yellow birch & didn't realize it.

 

[lambs]

My guess is you didn't bump anything out of tune; that is since you have basically a new saw, it probably was ready for a little carb tuning after a few tanks of fuel. Keep an eye on it and don't let it start running lean. Tweak as needed to keep it a little rich out of the cut at WOT and you should be fine.

 

[BP021]

I've ran Echo last few years & getting use to the Stihl. Big difference in the 2. I'm not a huge saw guy, yet . I'm learning.