Stumped by Stihl MS391 Chainsaw

[Smart]

I always lean toward carburetors , especially the float valve and seat. If not that, check the spark arrestor screen near the muffler... it will cause some no starts....




on edit ...glad you figured it out.

[Killer]

Good catch

[merlin]

You did good on that one.

[BTLowry]

LOL

Not one person suggested a ground wire issue

Glad you got it going.

BTW, not that I don't trust anyone, just easy to mess one up. I have 3 older Stihls that I would not trade for 10 new ones either

[krisw]

I loaned my brother a saw once. Ran fine when he got it. When he brought it back, he told me he had to choke it to kill it. Come to find out he was messing with it and knocked the wire from the kill switch loose.

[coker737]

Got it! I can’t explain it but the return ground wire from the magneto was loose. So I was getting spark but... ????

Dang, Just when i was going to say "Throw It Away and buy another" LOL

[Smithwr]

Check the return ground wire from the magneto!!

[hpdrifter]

Got it! I can’t explain it but the return ground wire from the magneto was loose. So I was getting spark but... ????

Good deal!

I had a Stihl once. Bought it from an acquaintance at work.

It would run fine. Would rev up with no hesitation and idled good.

Go to cut a piece of wood and it would die.....before even touching the wood.

I was going out of town a lot on semi-annual inspections so took it to a small engine shop. They cleaned carb, new gas, and said it ran fine.

A couple weeks later, was gonna cut up a fallen tree. Fired up real nice, revved up and warmed up mighty fine. Go to cut and it'd die....before even touching the wood.

Put new gas in and tried again. Same thing. This went on for an hour or so.

Never cut so much as an inch of wood with that thing. I think I found a saw that was a lazy as I am!

Sold it cheap,.....I told the buyer what he was looking at.