038 stihl leaking gas

[xrem20]

I need some help, I have a 038 mag that when turned forward leaks gas out the muffler. I found a small hole in the impulse line, is there anything else that maybe causing the fuel to leak through the piston that I should check before I reassemble it?

 

[Fish]

Well a new impulse line is definitely needed.

A complete carb rebuild is needed for the flooding..

 

[xrem20]

038

thanks fish I will try that, do you know if the carbs from a 038 av and a 038mag 2 are interchangeable?

 

[Jacob J.]

The carbs would be the same if they're both Bing, but the early 038 AV saws came with a Tillotson. You could use either on your 038 M2. Probably what's happening is your inlet needle is stuck open for reason, allowing fuel to run through the carb while the saw is parked. The metering diaphragm could be sucked in, the inlet needle lever could be set too high, or debris could be holding the needle open.

If you do go to actually switch carbs, I'd recommend the Bing if you can find it. Like Fish said, it's quite likely you just need a rebuild.

 

[xrem20]

038

Jacob
the 038 av is a tilliston the mag is a bing. So I should be able to run the tilliston on the mag to diagnose the problem, and if that is then rebuild the bing and use it on the mag. Thanks for the info

 

[Mad Professor]

The very early 038 AV carbs are smaller than the super or Mag carbs. This (change the carb too) is mentioned for 038 AV conversion to a Super in the Stihl shop manual

The Tilliston from a 038S, and Bing from 038M, have the same size venturi and I've switched them back and forth, even mix settings were about the same.

 

[subhunter]

Sorry about HIJACKING your thread.

My 038 is also leaking gas. It leaks by the vent tube. The vent was old and I replaced it. Now when it gets hot the plugs in the tube are letting gas get past them and it still leaks gas. Is there a certain way these plugs are supposed to be inside the vent tube ?

 

[adkranger]

Sorry about HIJACKING your thread.

My 038 is also leaking gas. It leaks by the vent tube. The vent was old and I replaced it. Now when it gets hot the plugs in the tube are letting gas get past them and it still leaks gas. Is there a certain way these plugs are supposed to be inside the vent tube ?

Hmmm, new vent tube, you re-installed the grub screws and it stihl leaks? Is the hose you used the same diameter? If there are two grub screws in the vent tube make try separating them a bit, not butted right up next to each other. So there's a gap between them, see if that helps.

 

[subhunter]

I bought a stihl vent tube with two screws in it. One at each end of the tube I screwed them to where they were at each end. When it does leak it has gas inside the vent tube and it just keeps seeping out. SHould I try just one grub screw? THANKS

 

[adkranger]

OK, just so I understand correctly, you have one grub screw in each end of the vent tube? If so, try removing the one at the tank end and run it with one screw. The other option is to put it in above the other screw, both at the outlet end with a slight gap between them. Give that a try.

 

[subhunter]

OK, just so I understand correctly, you have one grub screw in each end of the vent tube? If so, try removing the one at the tank end and run it with one screw. The other option is to put it in above the other screw, both at the outlet end with a slight gap between them. Give that a try.

Will do thanks alot

 

[Mad Professor]

I bought a stihl vent tube with two screws in it. One at each end of the tube I screwed them to where they were at each end. When it does leak it has gas inside the vent tube and it just keeps seeping out. SHould I try just one grub screw? THANKS

One grub screw should be at the vent end, the other 18 mm/3/4" from the tank end of the vent hose. ( as per The Stihl shop manual)