# Gas Leak



## djg (Jun 25, 2019)

I've got an older Stihl 038 chainsaw and it appears to be leaking gas. It leaks more when it's in the upright position so I've been storing it on it's side. It's NOT the gas cap. I've checked that, no wetness. I thought it might be the fuel line grommet between the gas tank and the carburetor compartment. And there is no gas pooling up inside the carb compartment. But when I set it down on a surface, I can see gas accumulating and some dripping when I pick it up to use it. It appears to be coming from the bottom side.

I used it today, but I won't anymore until I get it fixed. Just trying to avoid an expensive shop visit.


----------



## pinky (Jun 25, 2019)

How long has the gas been in it? Could be varnished up and the needle jet is not seating properly. $5 fix if that is where it's coming from. Watch a you tube video on how do clean and replace.


----------



## Graybeard (Jun 25, 2019)

I had a stihl weed wacker leak. I replaced the cap and found it was the clear gas tube. It had soften due to time and gas. Something else to check.


----------



## djg (Jun 25, 2019)

pinky said:


> How long has the gas been in it? Could be varnished up and the needle jet is not seating properly. $5 fix if that is where it's coming from. Watch a you tube video on how do clean and replace.



Thanks for the reply, but wouldn't I see gas in the carb/air filter compartment. I'll check again tomorrow. The gas is new, but it did have last year's gas in it.


----------



## djg (Jun 25, 2019)

Graybeard said:


> I had a stihl weed wacker leak. I replaced the cap and found it was the clear gas tube. It had soften due to time and gas. Something else to check.



The gas cap is not leaking, no gas dripping from the cap. And the tubing is intact or else there would be gas in the carb/air filter compartment. I'll check that too tomorrow. Thanks.


----------



## Lou Currier (Jun 25, 2019)

@woodtickgreg

Reactions: Agree 1


----------



## Wildthings (Jun 25, 2019)

@woodtickgreg

Reactions: Agree 1


----------



## ripjack13 (Jun 25, 2019)

I'm not sure if anyone knows, but Greg does chainsaw and small engine stuff.
Lemme tag em....

@woodtickgreg

Reactions: Funny 3


----------



## ripjack13 (Jun 25, 2019)




----------



## rocky1 (Jun 25, 2019)

@woodtickgreg

Reactions: Like 1


----------



## Nature Man (Jun 25, 2019)

@woodtickgreg

Reactions: Like 1


----------



## woodtickgreg (Jun 26, 2019)

Good morning guys, lol.
It could be many things, cap not venting, bad fuel lines, carb leaking, bad vent if it has one, or a bad case gasket. You really have watch it to see where it's coming from. The fact that I'd doesn't leak when it's on its side tells something. Is the tank full when you do this?


----------



## djg (Jun 26, 2019)

woodtickgreg said:


> Good morning guys, lol.
> It could be many things, cap not venting, bad fuel lines, carb leaking, bad vent if it has one, or a bad case gasket. You really have watch it to see where it's coming from. The fact that I'd doesn't leak when it's on its side tells something. Is the tank full when you do this?



Not sure about gas level; I'll have to check everything out today and get back to you all.


----------



## djg (Aug 9, 2019)

Update: Finally got around to looking at it again. As I said there was no standing gas in the carburetor area and none on the vent tube assembly. I had been laying it on it's side and no noticeable gas came out. When I lifted it up-righted, I could see gas leaking out of the tank. There appears to be a crack in the gas tank.

The question is now, has this ever happened to anyone and how did you fix the problem?
I would like to just find an epoxy made for cast Aluminum and patch the tank. I would have no problem cleaning off the gas/oil residue and removing paint and roughing up the surface. Any ideas on the epoxy?

As a last resort, I guess I could change the whole tank. I briefly looked on ebay and aftermarket tanks run about $30. But I'm not sure on aftermarket products or how to tackle the project.

Any ideas on how to address this leak would be appreciated.

Thanks


----------



## rocky1 (Aug 9, 2019)

Drain the tank, scuff it good with sand paper, and use JB weld. 

There is a product called Seal All you can use to seal the crack itself, it will set with gas in the tank. Then JB Weld over it.

Reactions: Thank You! 1 | Agree 1


----------



## djg (Aug 9, 2019)

Thanks, I'll pick some up and give it a try. Haven't had much luck with JB Weld on other projects.

Edit: Why put JB Weld over the top? According to the specs, Seal All is suppose to be pretty tough?


----------



## rocky1 (Aug 9, 2019)

The seal all is tough, but it's kinda like a glue, comes out the tube in semi liquid/gel state. Simply smear it over the leak, and it will seal some pretty good size holes. We were using it on auto gas tanks, catching flying gravel under cars. The Seal All, where exposed, wouldn't stand up to the gravel, hence sealing it, then applying the JB Weld over it. Made for a very durable repair.


----------



## woodtickgreg (Aug 9, 2019)

If your not going to replace the tank then Rocky's plan is sound. But for 30 bucks I'd just replace the tank and be done. After.arket stuff like that is usually ok, I have used many aftermarket Chinese chainsaw parts and most of them work fine. The Chinese have become masters at copying everyone else's goods and then selling them cheaper.


----------



## djg (Aug 9, 2019)

Yes I see what you mean. Comes out a little like Shoe Goo only a little thinner. I had the saw turned on the side and starter to sand down the spot I thought the crack was at. Turns out it was at edge or 'seam' (so real joint) of the tank. So I spread it out the best I could using a stick end of a swab. Started to sag so I inverted the saw until it set. I tried to force it around the corner (orange) too. Will put a second coat on in the morning and test it in the afternoon. If it's still leaking, then the crack must run up the tank and I'll have to remove the tank to get to that area.


----------



## djg (Aug 9, 2019)

woodtickgreg said:


> If your not going to replace the tank then Rocky's plan is sound. But for 30 bucks I'd just replace the tank and be done. After.arket stuff like that is usually ok, I have used many aftermarket Chinese chainsaw parts and most of them work fine. The Chinese have become masters at copying everyone else's goods and then selling them cheaper.



Agreed, it's turning out that I'll probably have to remove the tank (which I don't know how to do) either way. I just thought I saw a small crack and thought it would be quicker to slap a patch.

Reactions: Like 1


----------



## djg (Feb 19, 2020)

Hi again,

Long story short, I tried several times to patch the 038 gas tank that I posted about earlier. Cracked too bad so I bought a new tank. Yes I know I should have taken your advice and it would have it fixed by now. I'm having trouble (more hesitant) getting the old one off. In the photo, it looks like the air intake hose (for lack of a better term) is secured by a small hose clamp? Is there a nipple underneath the hose like you'd expect. I just hate tearing into something without knowing what I'm getting into.

Also, how does the frontside of the hose next to the carburetor detach.


----------



## woodtickgreg (Feb 19, 2020)

If your referring to the intake rubber tube, the large on with the clamp, it fits onto a round flange on the cylinder. Just loosen the clamp and pull it off. But first I would stuff a rag in it and blow off all the sawdust before tearing it down any further.

Reactions: Thank You! 1


----------



## djg (Feb 19, 2020)

Yes I planned to.

How does the intake rubber tube detach at the other end (handle)?


----------



## woodtickgreg (Feb 20, 2020)

I'm not sure what you are asking.
Pic?


----------



## djg (Feb 20, 2020)

The lower 'circle' at the bottom of the photo above is the other end of the hose. It looks like it's just pressed into the hole, but I don't want to just start pulling on it if there is a clip or something. My eyes aren't as good as they use to be.


----------



## woodtickgreg (Feb 20, 2020)

The inner metal ring may need to come out first and then just pull it through.

Reactions: Thank You! 1


----------



## djg (Feb 22, 2020)

@woodtickgreg ,

Quick question to further my education, What's the small black hose in the picture?

Thanks


----------



## woodtickgreg (Feb 22, 2020)

That's the crankcase pulse line, it's what makes the carburator pump fuel. It works off of crankcase pulses.

Reactions: Thank You! 1


----------



## djg (Feb 27, 2020)

Damn, just fought to get the manifold hose and clamp back on (yes I know I work slow). I was ready to put the vibration isolator screws in, to mount the tank to the saw, and it looks like the holes in the plastic tank aren't tapped. Anyone replace a gas tank with a plastic aftermarket tank and run into a similar situation?

I guess I'm going to have to find what metric size the bolts are and then find a tap.

I guess use a tapering tap first and then finish up with a bottoming taper?


----------



## Mr. Peet (Feb 27, 2020)

djg said:


> Damn, just fought to get the manifold hose and clamp back on (yes I know I work slow). I was ready to put the vibration isolator screws in, to mount the tank to the saw, and it looks like the holes in the plastic tank aren't tapped. Anyone replace a gas tank with a plastic aftermarket tank and run into a similar situation?
> 
> I guess I'm going to have to find what metric size the bolts are and then find a tap.
> 
> I guess use a tapering tap first and then finish up with a bottoming taper?



No, I have not.

How big of a difference is it between hole dia. and bolt dia? Are the tank holes supposed to be threaded? Often if they are close, I have heated up the bolt / screw and threaded it into the plastic. However, that is a touch and go thing with several influencing items.

Reactions: Thank You! 1


----------



## djg (Feb 27, 2020)

Thanks, I got out my magnifying glass (readers aren't doing it for me anymore) and the walls are indeed smooth. No threads. The old metal tank was threaded of course or else the bolts wouldn't have held.

I went out to the local Ace and sized the bolt, 6 mm x 1.00, and purchased a tap. It's a tapered tap not a bottoming tap, but the bolts don't have threads on the very tip, not self tapping though (I think -mag glass) so the very bottom of the whole may not need tapping. If the bolts don't tighten up like they should, I'll order a bottoming tap and wait....


----------



## djg (Feb 27, 2020)

A guy suggested I use these on a plastic tank. Any idea on what they are and how to use them?


----------



## Mr. Peet (Feb 27, 2020)

djg said:


> A guy suggested I use these on a plastic tank. Any idea on what they are and how to use them?
> 
> View attachment 181037



That is a coarse thread, he likely meant it would cut its on way, no tapping. How bad was the old tank? Shame you could not weld or braze...


----------



## djg (Feb 27, 2020)

I thought he was taking about using the other part as an insert nut somehow.

I did try gluing the old metal tank with SealAll, but I couldn't seal all the cracks. Plus I was worried about the tank holding up.


----------



## Mr. Peet (Feb 27, 2020)

djg said:


> I thought he was taking about using the other part as an insert nut somehow.
> 
> I did try gluing the old metal tank with SealAll, but I couldn't seal all the cracks. Plus I was worried about the tank holding up.



Maybe, but looks like the thread would be loose going into that hole.


----------



## djg (Mar 25, 2020)

Almost done. Hands haven't been cooperating and I had to order parts. Another question. I got a new grounding wire but since it's been awhile since I removed the broken one, I don't remember where it was connected to. See photo. I know the lug on the new (black) ground wire attaches under the cover bolt on the left (black arrow). But I'm not sure about the other end (pin) of the wire. I fished the black wire from the ignition the hole in the new gas tank and placed the pin (red arrow) into the trigger spring. I thought that's where the pin on the ground wire should go. Any help is appreciated.


----------



## djg (Mar 25, 2020)

Well while I was waiting on some help with the ground wire, I thought I'd install the rim sprocket that I got a couple of months ago. I thought it would be straight forward like on my MS 17o. No such luck. I had to take off the side cover to get to the gears. I think I have to gently pry the white plastic toothed piece off of the old sprocket? Is that right? The next question is how do I remove the gear on the right that rides on top of the clutch? Tried to gently pull straight up but a lot of resistance. Last, I'm guessing I need to clean up all the oily mess and once back together? Then regrease? Li wheel bearing grease?


----------



## Mr. Peet (Mar 25, 2020)

Clean it up first, then you may answer some of your own questions...

Reactions: Thank You! 1


----------



## djg (Mar 26, 2020)

I'm in the process of cleaning everything up at the moment. It feels like there is a gasket/bushing (red arrow) around the oil flow regulator (coming from bottom of saw). Is that true or is it just gunk buildup?

I think that gasket or ring is part #000 989 040. Can anyone tell me how to replace it? I really didn't want to remove oil pump, is it really necessary? I saw a video and it looked difficult to remove. I don't mind if it leaks a little oil.


----------



## Mr. Peet (Mar 26, 2020)

djg said:


> I'm in the process of cleaning everything up at the moment. It feels like there is a gasket/bushing (red arrow) around the oil flow regulator (coming from bottom of saw). Is that true or is it just gunk buildup?
> 
> I think that gasket or ring is part #000 989 040. Can anyone tell me how to replace it? I really didn't want to remove oil pump, is it really necessary? I saw a video and it looked difficult to remove. I don't mind if it leaks a little oil.
> 
> View attachment 183114



Don't recall a gasket...but believe there was a vibration bushing. Not that big of a deal once you get it cleaned first.

Reactions: Thank You! 1


----------



## djg (Mar 26, 2020)

P.S. I got it cleaner than the photo above. Thanks!

And what I could find about the bushing, it a spongy rubber dust cuff.

I'm having trouble with the on/off lever switch on the new plastic gas tank (cheap) rubbing on the bottom side of the new air filter that came with it. Can't use old air filter because it's another part that's worn out. But I can deal with that. I'll probably just file a little clearance off the bottom of the filter where it hits. Guessing I only need a mm.

Reactions: Like 1


----------



## djg (Mar 31, 2020)

Spare Part....This came with the new plastic tank and air filter. According to a parts list, it's a baffle which is sandwiched between the backside of the air filter and the intake of the carburetor. When I first tore into the saw, there was nothing there that looked like this (and I haven't lost any parts). But the saw has been worked on by others multiple times, so maybe they lost it.

If I use it as described, there will be a gap between the backside of the air filter and the intake of the carburetor, but the 'ring itself will seal the filter from the outside. Am I correct?

I'm assuming the orientation is that in the photo. This is the only orientation of the four possibles that covers up the carburetor fully.


----------



## Mr. Peet (Mar 31, 2020)

djg said:


> Spare Part....This came with the new plastic tank and air filter. According to a parts list, it's a baffle which is sandwiched between the backside of the air filter and the intake of the carburetor. When I first tore into the saw, there was nothing there that looked like this (and I haven't lost any parts). But the saw has been worked on by others multiple times, so maybe they lost it.
> 
> If I use it as described, there will be a gap between the backside of the air filter and the intake of the carburetor, but the 'ring itself will seal the filter from the outside. Am I correct?
> 
> ...



Sounds correct but defer to Tic...

@woodtickgreg

Reactions: Thank You! 1


----------



## woodtickgreg (Mar 31, 2020)

It is a needed gasket, helps to seal out dirt ingestion. Be sure to use it. I smear a little 2 cycle oil on all gaskets to help seal them and still allow you to take it apart later without tearing the gasket.

Reactions: Thank You! 1


----------



## djg (Mar 31, 2020)

woodtickgreg said:


> It is a needed gasket, helps to seal out dirt ingestion. Be sure to use it. I smear a little 2 cycle oil on all gaskets to help seal them and still allow you to take it apart later without tearing the gasket.



It does fit *between* the backside of the *air filter* and the intake of the *carburetor??
*
Is the *orientation* (flat on top) correct*??*

Thanks


----------



## woodtickgreg (Mar 31, 2020)

Match it to the carburetor for the orientation..

Reactions: Agree 1


----------

