Stihl 038 Woes

[wildwes]

I had a 038 Super that I chased issues with, rebuilt the carb, never would run right. It had one of the Tillotson carbs with the plastic plate on the side. Turns out the plastic was warped, so it was impossible to get it tuned and keep it right.
Swapping a good carb onto it and tuning it made the issues go away.

 

[HarleyT]

Does your saw have points?

 

[djg james]

Does your saw have points?

I don't really know. What am I looking for?

 

[HarleyT]

I don't really know. What am I looking for?

Take off the starter, and put up a pic of the coil and flywheel.

 

[djg james]

I have this carb:


Are Zama, Tillitson and Walbro carb kits different? Stick with Tillitson?

 

[wildwes]

That little plastic plate in it is what I have had problems with on the tillotsons, it can warp slightly and there isn't really anything you can do to fix it.

 

[HarleyT]

You ought to explore the points question.

 

[James Sawyer]

If you don't have plates, you can slip some rubber between the cylinder and muffler and carb mounts. On the carb sided, I used a fender washer and some stand-off on this MS034...its almost the same saw as your ms038. You can vacuum test thru the impulse port if you don't have a spark plug test fitting. I made mine from old plug by removing the porcelain and tapping it for a fitting, probably easier to find a barb fitting then this press-lock. Most likely the decompress valve will have a slight leak. Make sure you test pressure as well as vacuum. My advice on that old of a saw is just to replace all the rubber and test afterwards.

 

[Oletrapper]

As I stated in the "Firewood Scrounging" section, I'm resurrecting this thread because the saw is acting up in the same manner. I'll recap everything I've done to it now so you don't have to read through the whole thread.

This may not apply to the current problem, but i don't want to leave anything out. Years ago I cracked my fuel tank and eventually installed a plastic AM tank. It worked fine for a while but the choke/shut-off lever was hard to engage and finally broke. I replaced it with a AM lever. Ever since, WHEN COLD, I have to shoot some 50:1 mix into the air filter before I choke it. Saw started right up. Wouldn't have to choke it once it was warmed up. It's like the choke lever didn't completely close the choke. Anyway minor inconvenience that I could live with. And probably not related to current problem.

Back it January, the saw would die once it hit wood and I would have to pump it to get through the wood. This is what I posted about initially in this thread and these are the things I've done to get it working smoothly again.
1) Change fuel line/filter
2) New spark plug
3) Cleaned air filter in case oil residue from evaporated 50:1 was clogging the filter
4) New impulse line
5) Checked spark arrestor screen
6) New gas tank vent

After I did this, it worked fine. I don't know what the actual problem was.

So now it May, it's acting the same, or worse. I shoot 50:1 into the air filter and it fires up, but only runs until it consumes that gas. Then it dies. Repeat, same. It's acting as if it's not getting any gas. Once I opened the gas cap and heard like a vacuum pop. I cleaned the fuel tank vent. But that didn't help. I've filled the tank up, tried to start it up and put it away. The next day, the fuel tank is half empty. No visible leaks around the flippy cap. I dumped the gas and put fresh in, tried to start it, put it away and next day noticed 1/2 tank of gas left. Don't know if that's related to the current problem.

So today, I'll change the impulse line again. It feels a little spongy. The line I bought was sold as impulse/gas line so I would think it's not that. I'll change the fuel tank vent too. And if I have a new fuel filter, that will be replaced.

Any other ideas?

Was the impulse line an OEM. I have found that aftermarkets sometimes kink. Might want to check that. jmho OT

 

[wildwes]

You ought to explore the points question.

Not on an 038, but I have had some really weird issues with condensers on other points saws, so I agree, it's definitely worth investigating.

Was the impulse line an OEM. I have found that aftermarkets sometimes kink. Might want to check that. jmho OT

I have had that problem with AM fuel and impulse lines on 026 saws. They are longer than original, and worked fine once I trimmed about a 1/2" off of them.
Of course, I have also had issues buying OEM, both from the local shop and online, and getting lines that must have been sitting on a shelf because they split very shortly after installation.

 

[djg james]

Was the impulse line an OEM. I have found that aftermarkets sometimes kink. Might want to check that. jmho OT

I had replaced the impulse line months ago with what was sold as bulk impulse/fuel line. Right diameter so it worked. Replaced again with same when I saw the small crack. But now that's not the problem.

 

[stihltech]

#1 get rid of the carb with the plastic plate on the metering side. Known issue. Discontinued not too long after the inception. Also has a high speed jet built into it that wears. Bing was the answer, but very hard to find and expensive.
Good catch on the pulse hose. Another common issue.
Pull the hose off the carburetor and plug it. That will eliminate the carb leaking through.
As for the vent, yes, it will push some fuel through the hose when off the carburetor. Normal. No vent let's all pressure of the tank. A little pressure is a good thing.
If it says 038 and nothing else, and the fuel tank is metal, good chance it has points.

 

[wildwes]

#1 get rid of the carb with the plastic plate on the metering side. Known issue. Discontinued not too long after the inception. Also has a high speed jet built into it that wears. Bing was the answer, but very hard to find and expensive.
Good catch on the pulse hose. Another common issue.
Pull the hose off the carburetor and plug it. That will eliminate the carb leaking through.
As for the vent, yes, it will push some fuel through the hose when off the carburetor. Normal. No vent let's all pressure of the tank. A little pressure is a good thing.
If it says 038 and nothing else, and the fuel tank is metal, good chance it has points.

They're hit or miss, but some of the Bing knockoff carbs are actually decent. I have a Raismann branded knockoff that is close to the real thing. I'd rather have a real one, but if you can't find one...

 

[djg james]

If you don't have plates, you can slip some rubber between the cylinder and muffler and carb mounts. On the carb sided, I used a fender washer and some stand-off on this MS034...its almost the same saw as your ms038. You can vacuum test thru the impulse port if you don't have a spark plug test fitting. I made mine from old plug by removing the porcelain and tapping it for a fitting, probably easier to find a barb fitting then this press-lock. Most likely the decompress valve will have a slight leak. Make sure you test pressure as well as vacuum. My advice on that old of a saw is just to replace all the rubber and test afterwards.

I like the spark plug fitting you made. I was going to leave the spark plug in and use the impulse line to attach to the gauge. Is that doable? And I've sheet rubber for the muffler side and a rubber stopper that I can secure in the intake manifold boot using the carb studs. Of course after removing the carb.

 

[djg james]

Thanks everyone for your thoughts and replies. I haven't had a chance to reply or address your ideas yet. I took the day off from the saw and I'll get back on it tomorrow.

 

[djg james]

#1 get rid of the carb with the plastic plate on the metering side. Known issue. Discontinued not too long after the inception. Also has a high speed jet built into it that wears. Bing was the answer, but very hard to find and expensive.
Good catch on the pulse hose. Another common issue.
Pull the hose off the carburetor and plug it. That will eliminate the carb leaking through.
As for the vent, yes, it will push some fuel through the hose when off the carburetor. Normal. No vent let's all pressure of the tank. A little pressure is a good thing.
If it says 038 and nothing else, and the fuel tank is metal, good chance it has points.

You and @wildwes mention a plastic plate on the Tillotson carb. The outside plates are metal. First off, I'm not sure the carb is the problem yet. So getting a new carb (I paid $80 for this one) is not a option now. If there's a plastic plate in side, can't I just get a carb kit? It would have to be a Tillotson kit right?

Can I leave the plug in and attach the impulse line to the gauge?

This saw originally had a metal tank, so I'll look for points, etal tomorrow.

 

[wildwes]

You and @wildwes mention a plastic plate on the Tillotson carb. The outside plates are metal. First off, I'm not sure the carb is the problem yet. So getting a new carb (I paid $80 for this one) is not a option now. If there's a plastic plate in side, can't I just get a carb kit? It would have to be a Tillotson kit right?

Can I leave the plug in and attach the impulse line to the gauge?

This saw originally had a metal tank, so I'll look for points, etal tomorrow.

The plastic plate is in between the carb body and the outside plate on one side. It may not be the problem with your saw, but they are known to cause problems. You can find the Bing knockoffs, or sometimes bings in need of a rebuild kit, for $30-$40 if you're patient.

A carb kit won't fix the plastic plate, as it is a part of the carb, not really a replaceable part. They work fine until they don't.

It's worth checking to see if it had points, although even if it was a points saw it may have been converted to electronic by now. Basically all that is required to do so is a coil swap, and I have a early 038AV that I converted to a 038 mag that was originally a points saw, that was already converted to electronic when I bought it from a board member here with a toasted top end.
FWIW, it's also pretty easy to install a chain brake on those saws if yours doesn't have one and you want one.

 

[djg james]

The plastic plate is in between the carb body and the outside plate on one side. It may not be the problem with your saw, but they are known to cause problems. You can find the Bing knockoffs, or sometimes bings in need of a rebuild kit, for $30-$40 if you're patient.

A carb kit won't fix the plastic plate, as it is a part of the carb, not really a replaceable part. They work fine until they don't.

It's worth checking to see if it had points, although even if it was a points saw it may have been converted to electronic by now. Basically all that is required to do so is a coil swap, and I have a early 038AV that I converted to a 038 mag that was originally a points saw, that was already converted to electronic when I bought it from a board member here with a toasted top end.
FWIW, it's also pretty easy to install a chain brake on those saws if yours doesn't have one and you want one.

Thanks, I'll check your items tomorrow. I'm (my Dad) am the original owner. And it already has a chain brake.

 

[cwballistics]

FWIW, this is what I found here somewhere to switch to so as to ditch the plastic metering level.

Tillotson HE19A

https://www.amazon.com/dp/B07GT64MCT?ref=ppx_pop_mob_ap_share


Haven’t tried it yet, since the saw I ended up getting had an original Bing on it.

 

[djg james]

FWIW, this is what I found here somewhere to switch to so as to ditch the plastic metering level.

Tillotson HE19A

https://www.amazon.com/dp/B07GT64MCT?ref=ppx_pop_mob_ap_share


Haven’t tried it yet, since the saw I ended up getting had an original Bing on it.

Sorry, I don't understand. I have a Tillotson carb. Is this an updated version of what I have and has a non-plastic metering level (whatever that is ). And from what I gather from you and others, Bing carbs are better?