Hot start problem, stihl model 025

[usmc1978]

I've had this 025 for years. Heated with wood for 4 years, used it a ton. Use now is incidental, maybe once a month or less. A couple of years ago it developed this problem. It starts cold, I run it a good while, maybe until out of fuel but maybe not. I shut it off to clear branches and such. Then it won't start. Sometimes I've refueled, sometimes I haven't. It doesn't do this all the time, maybe about a third of the time. After i sits for a while, it usually starts.

I could probably use a new air filter. Maybe a plug, maybe. But what I don't get is this: if it were either of those issues, then why did it start to begin with, when it was cold? And why is it that it's only now and then that it doesn't restart when it's hot, not all the time?

Any insight would be appreciated. I don't know if this is a clue, but when I take the back cover off, there's a clear, vertical tube about an inch or two long, on the left side. Sorry, but I don't know the nomenclature. Anyway, when it won't start, there's usually fuel in this tube and bubbles coming up through it. I don't know that this is exclusive to the non-starting, because when it does start there's no need for me to take the cover off. For all I know, this might be bubbling fuel every time I try to start it.

 

[Jean Christophe Chuine]

.If it's a problem that occurs mainly when hot, on this machine I would think more about the carburetor that needs a little renovation, buy a gasket kit and replace them, that should do it some good.

 

[Stihl 99]

Sounds like a carburetor issues.

 

[usmc1978]

Thanks!

 

[Paul]

I agree with Jean probably carb issues. Coils on these machines gave very little trouble.
The tube that you are talking about is the tank vent. Simply a hose with a grub screw in it. Crude but it works. Not unusual for you to see bubbles from it.

 

[Leon Couper]

If all the other stuff you do fails don't count out the coil. I have had chainsaws brought to
me to fix with the same problem, runs and starts good cold but will not start when hot.
Best way to sort this one out is next time it does it pull the plug out and leave it connected
and short it out on the saw and make sure you have spark. Coils can be hard to pin point at times
as they can either completely fail and won't start at all or break down when hot and won't start till
they cool down. Also what the other guys have told you it worth checking out as well.

 

[STIHLTECH]

An inline spark tester comes in handy on a hot coil failure.

 

[Leon Couper]

Yes I have one an inline spark tester and are a great tool and easier than trying to hold the
plug and work the chainsaw at the same time.