won't run after starting

[wwager]

I have a stihl 025 that starts as normal and will run at cutting speed for about 30 seconds then shut itself down. Have to let it sit for a minute before it will restart and then it does the same thing again. Acts like it is running out of fuel.

 

[wwager]

what I have tried:
Fresh fuel
New Air cleaner
New plug
removing screws from plastic gas tank breather tube
what should I try next?

 

[fishhuntcutwood]

A couple of quick questions to help us out-
1. Have you played with the carb settings?
2. Has the saw been sitting for a while, and if not did this problem start suddenly, or has it run this way for a while, gradually getting worse?
3. Can you keep it running by modulating the throttle?

Could be improperly adjusted carb, a carb in need of a rebuild, an airleak or air seepage somewhere. And it could be a clog somewhere in the fuel system, and it is in fact running out of fuel to the combustion chamber.

Jeff

 

[wwager]

1. Have you played with the carb settings? No
2. Has the saw been sitting for a while, and if not did this problem start suddenly, or has it run this way for a while, gradually getting worse?
Has done this on and off, usually worked out of it, and ran fine after that.
3. Can you keep it running by modulating the throttle?
No
Saw is approx two years old -
Could be improperly adjusted carb, a carb in need of a rebuild, an airleak or air seepage somewhere. And it could be a clog somewhere in the fuel system, and it is in fact running out of fuel to the combustion chamber.

Jeff

 

[fishhuntcutwood]

New to you two years old? If it's an 025 and not an MS 250 it's at least as old as 2001. The carb would be the easiest thing to look at. Carbs need to be retuned and adjusted more often than most folks think. It's possible it's been at the factory setting since new. It would need to be readjusted. You can do a search on this forum on how to do that, and there's plenty to ready.

You mention that it does this off and on. Is it dependent on the saw being cold, warm or hot?

I'd recommend trying the carb angle first. A retune, which is easy. And then a rebuild, which is also very, very easy. Carb kit should cost you about $12-$15. If that doesn't work, you need to start looking for airleaks. That's what I'd try next. Try the easiest stuff first.

Of course someone will probably get on here and say, "Oh yeah, that's a...." Give it time, and you'll ge more responses on here. Let us know how it turns out.

Jeff

 

[wwager]

No, I bought it new (but maybe it was a little longer than two years ago -- no telling how long it was sitting on the dealer's shelf. Anyhow, I will look for the carb readjustment information. Someone suggested that I remove the carb adjustment screws and spay WD-40 into the jets to clean them out. Is that a good suggestion?

 

[andrethegiant70]

I think it would be a good idea to eliminate the ignition system as a problem, since it would be easy to do this. Run it, wait 'till its had it's "fit" and stops running, pull the plug quickly and see if it still has a spark. Lifetime warranty on ignition! It'd be nice if someone else had to pay for the fix.

 

[fishhuntcutwood]

Good call Andre. That's one of the reasons I asked about the saw being hot or not. Maybe the heat is getting to that coil and causing problems.

Jeff

 

[wwager]

No, I don't think the saw runs long enough to get the coil very hot -,
Anyway, it will restart after about a minute, but does the same thing like it is running out of fuel - Makes a deep throaty sound before it quits. Is there anything like a fuel-pump diaphram? My other question is if it is pulling in air from somewhere, where might that be?

 

[fishhuntcutwood]

You describing it as a deep throaty sound almost makes it sound like a rich condition to me. And a saw can and will die if it's set too rich.

As far as air leaks, wow where to start? Case seals, carb seat, carb itself, cylinder to case mount, carb-to-case elbow, impulse line...

Jeff

 

[West Texas]

Next time it dies, pull the plug and check it to see if its wet, sounds like its getting too much fuel while running.