Stihl 031 Extremes

Tom from Buckeye Lake · Posted: Tue Nov 13, 2012 9:31 am Post subject: Stihl 031 Extremes

1977 Stihl O31AV. Been a great saw all these years. OK, the problem. After 6 months of non-use, fresh fuel. It wouldn't fire unless I pulled the plug and poured a little fuel into her. Then it would start, but just a few seconds. Tried several times.

Pulled fuel hose at the carb, tilted saw a little, fuel siphoned out hose, so thought fuel filter/hose OK. Pulled carb and installed kit with new gaskets/pump diaphragm/needle.

Tried to start it, fired once, release choke, pulled my arm off and didn't fire again. Pulled plug, flooded. Dried plug same event happened again. Said the He*& with it. Sat it in the garage for a week, thought I'll try again. Pulled rope, fired on 1st pull, then flooded again.

I've had better luck with rebuilding a four barrel carb.

What now? Head to a shop?

mjsnodgrass · Posted: Tue Nov 13, 2012 9:52 am Post subject: Re: Stihl 031 Extremes

just had the same thing happen. stihl shop says they no longer have the parts to fix mine. too bad. i loved that saw. good luck with yours.

dave2 · Posted: Tue Nov 13, 2012 10:09 am Post subject: Re: Stihl 031 Extremes

did you put a new spark plug in it? What brand of plug do you use? Should be by the german book either Bosch WSR 6F or NGK BPMR7A...

before you guys give up on them because parts aren't available, I may be able to get them here for you...

Bryan inIowa · Posted: Tue Nov 13, 2012 10:13 am Post subject: Re: Stihl 031 Extremes

If it's flooding that fast ,your needle and seat may be leaking . double check it , make sure clean . Make sure you got diaphram in the right way .

mkirsch · Posted: Tue Nov 13, 2012 10:38 am Post subject: Re: Stihl 031 Extremes

The needle and seat are messed up. It can happen on any saw. Had that problem with my ProMac 700... Pull twice, and the fuel would just pour out the muffler.

Mostly cuz I didn't know what I was doing. The arm that lifts the needle needs to be at a certain height or the needle won't close.

Butch(OH) · Posted: Tue Nov 13, 2012 1:32 pm Post subject: Re: Stihl 031 Extremes

As the last two posted I think. Problem is in the needle seat/ diaphram. One problem I have fixed many times for first time carb builders is the gasket goes on LAST on the fuel pump side and FIRST on the diaphram side. If the diaphram is installed first it is too close to the lever and causes what you are experiancing. There is also an assembled hieght for the lever. Some carbs it is flush with the machined surface, some not. Rebuild info abounds on the internet just search your carb model and make

Butch(OH) · Posted: Tue Nov 13, 2012 1:33 pm Post subject: Re: Stihl 031 Extremes

Forgot. If you have to take it to a shop the guys in Utica are real good.

LJD · Posted: Tue Nov 13, 2012 3:29 pm Post subject: Re: Stihl 031 Extremes

Any chance the original problem was the impulse hose (not fuel hose) and then after pulling the carb apart - you've created an additional problem? Broken impulse hoses was a big problem in 041s. Not so much in 030s and 031s though.

Tom from Buckeye Lake · Posted: Wed Nov 14, 2012 4:45 am Post subject: Re: Stihl 031 Extremes

Thanks for the replies.

I'll pull it apart again and have a look. Might be a few days and get back with you.

Allis Chalmers	Case	Cockshutt	Farmall IH	Ford 8N,9N,2N	Ford
H. Ferguson	John Deere	Massey	Minn. Moline	Oliver	All The Rest