Stihl Kill Switch Problem

[mmstihl038]

I just registered after buying an old Stihl online that I haven't received yet. Apparently, it has a problem with the kill switch and I will have to choke it to shut it off. I saw this same problem mentioned for other saws indicating that it's a common problem, but I could not find any reference to fixing it. Can someone tell me what usually causes this and what I will likely have to do to fix it?

The model is 038 AVEQ (not super or magnum), which i think has the four position switch; off, run, half choke, full choke. I read on this site someone saying these switches had problems, but a solution wasn't mentioned and I don't see parts online related to this.

Buying a doner saw or a part from someone here or on ebay seems like an obvious solution. Does this saw share the same part number with other models as well, say a 028AV or 041AV of the same era? I saw this same problem mentioned recently in the auctions for an 041AV.

One other question. I see that this saw originally came with a max bar of 20". It's got a 24" bar, which looks very worn. If I replace it would I be better off with a 20" or another 24? This saw looks pretty beat up. If the compression isn't good I plan to just go ahead and buy a new jug and piston right off the bat. I understand that I can put the 52cc Magnum on it and gain about 1hp. I see these aftermarket for $110.

In that case 24" seems reasonable. I'll be using this saw to cut pine and aspen for my own firewood use, maybe I'll cut for an occasional job, as I have friends in the biz and could use it to pick up a little extra spending money. I'm at 9,000ft elevation in Dillon, Co. We have a serious pine beatle kill problem here with the lodgepoles and there's lots of cutting work, I think as much as anyone wants to do. But 20" is probably long enough for most of what I'll be cutting.

Thanks

 

[Lakeside53]

The 038 have a very simple mechanism - A wire from the coil to a spring inside the air fiter box. A ground wire from the left back screw on the top shroud to a small sleeve that mounts on the throttle shaft. Short these two together, and it kills the ignition.

The sources of problem;

- The coil is bad (rare)
- The spring and sleeve don't make contact, usually because the spring is bent due to operating or adjusting without the air cleaner in place - don't!
- The ground wire is broken at the shroud bolt.

If the spring is fussy just replace it. They only cost $2 or so.
The saw will run fine with a 24 inch bar, but 9000 feet will take its toll, and you'll need to retune the carb.

 

[mmstihl038]

Thanks for such a quick response. Really appreciate the advice. Tells me right where to start lookin'. I ordered an owners manual from Stihl and original parts numbers manual on ebay. I think this is different from the service manual, so I will probably get that too because from everything I've read here I'm led to believe that if I take care of it as long as I can get parts there's no reason why it shouldn't last me a lifetime. Also read here about all the common problems (ie pulse line, piston scarring, etc...). So I will go through the saw and check the usual culprits and getting it runnin' tiptop.

 

[mmstihl038]

Oh, yes. Retuning carbs is something I'm very familar with, as I have two carburated car engines up here. I run an old Jimmy up over 12,000 ft on trails. For cars trick is overcarburating to ram more air into the engine. That way you don't have to cut the gas flow back so much with tiny jets and big needles to get the right air fuel mixture. At 12,000ft with the carb you'd normally use at sea level, you have to lean it out to the point where it will barely run starved of both gas and air.

Are there bigger carburators for these saws or other ways to increase airflow? Other than removing air filter obviously.

 

[Lakeside53]

Never remove the airfilter on a saw - you will take out piston in short order.

If your 038 has a Bing carb, you should be able to tune (lean out) for 7-9000+ feet. Don't "peak" it - set for the "4-stroking" sound at WOT, with bar and chain. Best to check with a tach that you are still within allowable RPM limits. Check with other pro users or saw shops in your area -they'll be the best advise you can get for your local conditions.