A running conundrum

[I Know Something]

Here's what happened.

Got me a bar and chain today. Eventually got it on. Bar wouldn't fit. Had to slightly file the OEM Stihl bar. Odd. Took it to the garage to cookie up some 12 inch dead oak logs. Started up just fine. Idled about 30 seconds and hit the first log. Died half way threw.

Tore it down a bit and plug came out. Plug was clean as well as the inside the plug hole. Put it back together. It started back up.

Now, it would bog down and died. Sounded like starving for fuel. Took the fuel cap off. Everything looked fine. Pulled the cord. Started back up. Odd.....

Fuel tank vent was starting to make sence. Ran for a bit and bogged. Open fuel cap, put it back on and it ran fine for a small bit. Did this rotation for 5 minutes or so. Then. It took off and ran fine. I'm half way threw its first tank. This can't be part if the break in period.

Any of you run into something like this?

 

[Deets066]

What saw?

 

[Deets066]

Sounds like AM fuel system problems

 

[I Know Something]

What saw?

The 660 kit saw I put together.

 

[Deets066]

Sounds like AM fuel system problems

 

[I Know Something]

Sounds like AM fuel system problems

I honestly dont know. I just thought it was weird that releasing vacume pressure from the fuel tank fixed it for a while. Or....seemed to?

 

[Deets066]

I honestly dont know. I just thought it was weird that releasing vacume pressure from the fuel tank fixed it for a while. Or....seemed to?

I’d start by putting an oem impulse line on.

 

[I Know Something]

I like the idea. I'll look into it. I'll get one ordered.

 

[Stump Shot]

Here's what happened.

Got me a bar and chain today. Eventually got it on. Bar wouldn't fit. Had to slightly file the OEM Stihl bar. Odd. Took it to the garage to cookie up some 12 inch dead oak logs. Started up just fine. Idled about 30 seconds and hit the first log. Died half way threw.

Tore it down a bit and plug came out. Plug was clean as well as the inside the plug hole. Put it back together. It started back up.

Now, it would bog down and died. Sounded like starving for fuel. Took the fuel cap off. Everything looked fine. Pulled the cord. Started back up. Odd.....

Fuel tank vent was starting to make sence. Ran for a bit and bogged. Open fuel cap, put it back on and it ran fine for a small bit. Did this rotation for 5 minutes or so. Then. It took off and ran fine. I'm half way threw its first tank. This can't be part if the break in period.

Any of you run into something like this?

Yes
Remove the tank vent and get the lips of the duck bill valve inside to separate.

 

[angelo c]

throw another carby on for chits and giggles. fuels today are running amuck with our beloved OPE. Check the impulse like Deeter said too. pressure test everything after none of the above chased the gremlins away.

 

[I Know Something]

And now we understand why I did this as a "winter project" lol

 

[Marshy]

The problem is within the circle.

Anything on those are suspect. Cannibalize a known good saw until the issue goes away.

 

[Lone Wolf]

The problem is within the circle.
View attachment 170465
Anything on those are suspect. Cannibalize a known good saw until the issue goes away.

No joke!

 

[drf256]

The problem is within the circle.
View attachment 170465
Anything on those are suspect. Cannibalize a known good saw until the issue goes away.

Bingo

Could be anything.

Check your piston to make sure those 30 seconds weren’t super lean and toasted it.

The problem can be tank vent or anywhere from the fuel filter to the cylinder intake spout.

The tank vents are notoriously bad. Make sure the valve inside opens. Try a quick run without a fuel filter. Check impulse line, though idling/starting might be bad if that was the culprit. Try another carb, the ones supplied are notoriously bad. Also try a new plug.

Just so many things can be bad. The 440 kits made us all nuts and the culprit was too long of an impulse barb bottoming out on the side of the impulse and causing intermittent blockage of the line bore.

 

[I Know Something]

So far the only thing going on is it was bogging down and dying after about 10 seconds or so until you crack the fuel tank. I'm going to start with the vent when I get off work.

Thanks for the idea's of what else I can look at. Much appreciate the constructive response.

 

[Stump Shot]

So far the only thing going on is it was bogging down and dying after about 10 seconds or so until you crack the fuel tank. I'm going to start with the vent when I get off work.

Thanks for the idea's of what else I can look at. Much appreciate the constructive response.

That should get you to the next problem. Lol

 

[Larry B]

Here's what happened.

Got me a bar and chain today. Eventually got it on. Bar wouldn't fit. Had to slightly file the OEM Stihl bar. Odd. Took it to the garage to cookie up some 12 inch dead oak logs. Started up just fine. Idled about 30 seconds and hit the first log. Died half way threw.

Tore it down a bit and plug came out. Plug was clean as well as the inside the plug hole. Put it back together. It started back up.

Now, it would bog down and died. Sounded like starving for fuel. Took the fuel cap off. Everything looked fine. Pulled the cord. Started back up. Odd.....

Fuel tank vent was starting to make sence. Ran for a bit and bogged. Open fuel cap, put it back on and it ran fine for a small bit. Did this rotation for 5 minutes or so. Then. It took off and ran fine. I'm half way threw its first tank. This can't be part if the break in period.

Any of you run into something like this?

Sounds like a bad tank vent. Pull the tank vent and if you have a vacum pump test it. If you haven't got a vacum tester you can just suck on it to see if it vents. The kits use a generic white vent that are dirt cheap or you can get a black OEM one for about $10. You can also pull the vent and just run the saw and see if it starves for fuel.

 

[I Know Something]

UPDATE:

Took out the tank vent. And some transparent white plastics was in the bowl of the valve. Looked like plastic shavings from the lid that didnt quite make it off. It runs great now.

 

[Larry B]

 

[Stump Shot]

UPDATE:

Took out the tank vent. And some transparent white plastics was in the bowl of the valve. Looked like plastic shavings from the lid that didnt quite make it off. It runs great now.

Now you know something.