Mysterious problem Stihl 038 AVS

[elfinwood saws]

so if it starts on the next pull when upright it has not run out of fuel in the carb, did this fault happen all of a sudden or gradually or after servicing the saw?

[Charles Ekin]

Thanks Elfinwood Saws. It still cuts out even if the tank is full to the brim

Great idea about trying a different carb but I haven't got one. All diaphragms and gaskets are new and all the parts I took out (I took it all apart except the throttle shutter and the valve jet and gave it a good compressed air blast) seem in good nick.

Cheers

Charlie

[Charles Ekin]

I bought the saw on e-bay after an 038 Farm Boss of mine got knicked. For as long as I have had the saw it has done this. I bought it about 6 months ago, used it once, thought, great because it worked well to cut normally, then didn't use the saw for a couple of months by which time I had no recourse.

[elfinwood saws]

just a thought is the choke mechanism working corectlly, they have a choke flap in the airfilter.

[Rich2484]

just a thought is the choke mechanism working corectlly, they have a choke flap in the airfilter.

 

Ha I didn't think about the choke and I bet no one else did either. Check the flap is not loose and moving when the saw is turned on its side......

[JAMIE1]

Ive a Bing carb for the 038, if you pm me your details i will pop in the post and send it out to you then its another thing you can cross off the list. If it solves it, stick a fiver in a poppy appeal box in november if it dont you can have a spare carb, but still stick a fiver in a poppy appeal box.

[spudulike]

To clarify the stripping of the carb directly after the saw cuts out: - you would normally expect there to be fuel in the pumping section and also in the diaphragm to carb body void.

 

What I would do is to let the saw die and then pop off the top and bottom cover on the carb one at a time and see if the carb is dry or has around 1/4 teaspoon of fuel under each cover.

 

If the carb is dry, you aren't pumping fuel up to the carb, if the carb pumping section is wet but no fuel is in the diaphragm section then the needle valve or metering arm may be the problem.

 

Worth tying a couple of times to ensure it happens each time.

 

The vac/pressure test should really check the inlet boot, it sounds like this was bypassed with the method the agent used! Worth checking the inlet boot again, it is sometimes very difficult to see holes and splits in them but the problem sounds like lack of fuel to me.

 

It may be some muck in the carb or even some water in it - worth ultrasonically cleaning it if possible.

[GardenKit]

I have an idea forming, but cant quite see it through. It goes like this.

 

Saw upright, fuel being pulled up from tank to carb by pumping diaphragm as fuel lower than carb.

 

Saw on side, blade down, full tank of fuel. Fuel flowing by gravity into carb as fuel higher than carb.

 

Is there a potential flooding issue if the carb diaphragms are incorrectly fitted?

Any ideas, Spud? Stubby? anyone?.

[Charles Ekin]

Elfinwood Saws

Inspired idea about the air filter flap. Although the mesh and body of the filter are new, I took the flap and the split pin and spring out of the old one. I'll give that another check over as well.

Jamie1

Fantastic offer of the spare carb. It's a Bing I've got in there at the moment. That would be a great way of eliminating a few ideas. I'd be great to take you up on that. I'll send you my postal address.

Spud

Thanks for the details about the carb after it's cut out. As I've been offered a carb and I'm a bit pushed for time, I'll try that out first but if that doesn't work, I'll definitely be buying a new boot just for good measure.

Thanks again to you all for your interest and help. I've been, well, blown away, really.

Charlie

[spudulike]

Elfinwood Saws

Inspired idea about the air filter flap. Although the mesh and body of the filter are new, I took the flap and the split pin and spring out of the old one. I'll give that another check over as well.

Jamie1

Fantastic offer of the spare carb. It's a Bing I've got in there at the moment. That would be a great way of eliminating a few ideas. I'd be great to take you up on that. I'll send you my postal address.

Spud

Thanks for the details about the carb after it's cut out. As I've been offered a carb and I'm a bit pushed for time, I'll try that out first but if that doesn't work, I'll definitely be buying a new boot just for good measure.

Thanks again to you all for your interest and help. I've been, well, blown away, really.

Charlie

 

Lots of good guys on here with a wealth of knowledge and experience, let us all know how you get on and what it turns out to be - I think we will all be interested. Welcome to the forum by the way:thumbup: