025 quits

[danl]

Been trying to help Dad fix his 025. It quits after about five minutes and won't start again usually.
I started with a filter, then a new fuel line. I told him I needed to rebuild the carb, but I found one on ebay for $22.00 shipped.
I put that on Saturday night and thought I had it cured. He had a downed oak tree about 14" diam. and I cut 10 or 15 blocks and then it quit again.

Had all kinds of spark, I checked it when it cooled down just enough I didn't toast my fingers.

I did notice fuel bubbling in the tank vent line and when I pulled the vent line off fuel spewed out of it. Should it do that? I never noticed it on my saws before.

Also when I got it started again fuel was misting back out of the carb.

I have both jets backed off 1 turn from seats.

Any help????

 

[Scooterbum]

Sounds like a clogged fuel tank vent.Next time it won't start,open the gas cap to relieve pressure.Then try starting it without the choke.

 

[danl]

I tried that, still didn't start, unless the gas is hot enough it is locking up as soon as I put the cap back on.

I should have replaced the vent already. I only get to work on it on Saturday nights.
Is there any other thing that will cause gas to spray back out of the carb??
This is a brand new Stihl (walbro) carb.

He says no big deal, has the old Homelite XL12. He is 75 and the reflexes aren't fast as they used to be so I don't like him using that loud- heavy- slow, no chainbrake antique....

 

[Scooterbum]

You need to check for fire as soon as it shuts off,not after it has cooled some.Sounds like you may have a bad coil.

Also if you have fire when it shuts off,see if the plug is wet.Maybe flooding out.

Does it die in the middle of a cut? Or while it's idling?

 

[mtfallsmikey]

Hey Scooterbum!

why don't you go to town today and get a haircut???...wife's shop open today...she needs $$$$$$ ! ....open 'til 4

 

[Scooterbum]

All right !!!!!!!!!!!!

Do I really look like I need a haircut??

Picture like this kinda' leaves ya' speechless doesn't it ?

 

[ironman_gq]

fuel coming out of the carb like that could be from a very rich condition. My 025 was running pretty rich and would die after cutting for a while and would also get boggy in the cut real easy after about 5 minutes cutting. I adjusted the carb and was good to go. It could also be from crankcase pressure some how leaking past the piston and into the intake port and blowing out of your carb.

 

[Scooterbum]

Marginal compression could very well be the problem...........

 

[danl]

the compression issue was something I was wondering about but did not want to hear.

I didn't know if that could cause, pressure in the fuel tank.

Thanks

 

[ironman_gq]

pressure in the fuel tank could also be from the fuel warming up and expanding as it absorbs some heat from the engine

 

[Fish]

Pull the muffler and look at the piston before trying/spending anything more.

 

[danl]

Fish, I started to take the muffler off Saturday night, now I wish I had.
Actually started to. but when I started to take the nuts off it felt like the left one might twist the stud off. I will call Dad and have him soak it in wd40 or something before Saturday.

Are the studs threaded into the cylinder or the crankcase on that saw?

The muffler didn't remove like a 038 or 044 or 031 or any other saw I have desecrated... so I stopped while I was ahead.

Dan

 

[Fish]

No, they are not threaded, but the stud has a square head, and sets in a slot
so do not worry about any major damage, a buck or so at the most.

 

[ironman_gq]

the studs just fit in a slot they are very easy to replace and you should be able to get new ones from your dealer or online

 

[Fish]

Yeah, what he said!!!


If you break one, I'll send you one!

 

[danl]

I ain't broke it ..Yet

 

[danl]

I took the muffler off and the piston looks fine, not a mark on it.
And it seems to have good compression.
Removed the spark arrestor while I had it off.

Now I have new symptoms. It will no longer idle without the chain spinning.
When I turn the LA screw in enough to get the chain to stop, it dies.

Could I have a hole in the manifold? I was going to spray carb cleaner on the manifold to see if it affected the engine, but dad didn't have any.

How do I get to the manifold ?
My Stihl experience is limited to 038 and 044.
Thanks
Dan

 

[Chris J.]

Dan, do you have a service manual for the 025?

 

[danl]

Chris,
No I don't, sounds like I could use one doesn't it.

 

[stihl86]

A used carb off ebay???? If you do need a manifold, be prepared for about 2 hours. Saw has to come completely apart. Right down to the powerhead. You got a dealer that can press/vac test it for you to see if that's your problem? (an air leak)