Exhaust melted into oil tank

[coryj]

This is the Husqvarna 41 I was having carb problems with. Rebuilt the carb and set to factory specs and it ran well, but I didn't really run it much. Took it along today to cut some wood and it ran strong, it really surprised me until it started smoking.

Put it up for a while and richened up the H screw on the carb (thought it was lean and that caused the smoke). Cut a little more and it was okay.

I pulled the exhaust when I got her to check the piston and found this.



That's straight through into the bar oil tank. Any thoughts on why this happened?

This is what I was cutting, did I just push it too hard.

 

[cgraham1]

Were the muffler bolts tight?

 

[coryj]

Sure were. Everything looked normal upon disassembly.

 

[Chris-PA]

No, you didn't push it too hard - my plastic clamshells run flat out with buried bars all the time. Looking at how far forward the melt hole is, exhaust must have been leaking from the seam between the muffler halves. Given how much they overlap, I'd bet the two parts were not properly seated, or that something got bent and they did not fit together correctly, leading to a leak.

 

[Sleepy]

Is there a crack in the bottom of your muffler?
Looks to me like exhaust gasses were being blown on the plastic oil tank, somehow.

 

[coryj]

No crack in the muffler. I agree that exhaust must have been leaking since there was no melted plastic on the muffler, just not sure how.

 

[TBS]

Aren't the mufflers on these a two piece press fit muffler?

 

[coryj]

Yes they are. There is a flange on one half and the other half presses into it.

 

[TBS]

I bet the flange has separated on the bottom just a little.

 

[Chris-PA]

About all I can suggest other than getting a used case is to find one of these metal heat shields from a later 142e that came with a cat muffler (530055174). Maybe you could trim off the junk and use some sort of sealant to close off the hole in the case. It doesn't fit that close to the bottom though.

 

[TBS]

To fix the hole clean up the rough areas then take a piece of tin and shape to fit then take high temp silicon with afew screws to mount it. The tin will function as a heat shield too.

 

[Chris-PA]

https://www.partstree.com/parts/husqvarna/parts/530055174/ $2.67

 

[pgdalton]

I did the same thing to one of my saws by not paying close attention to the fitment after cleaning the arrestor screen. From the top everything looked good, but the bottom lip did not seat inside the flange, causing the same condition as your saw.

 

[svk]

Have to agree with the others, your muffler must be leaking.

Luckily the 41 and it's siblings and cousins are very common so you should be able to pick up a case for cheap. I had a 41 and cut a lot of wood with it, they are a good little saw.

 

[coryj]

I cleaned up the melted plastic as seen below. I cut some tin from an old bandaid container. I used rtv to seal it to the plastic and once it dries I'll skim coat the top side with JB weld and build up a bead of JB weld around the edge of the tin. Here's hoping this works. If it doesn't, 41s are plentiful as someone mentioned

 

[Thommo]

I like the idea of putting a bandaid on a chainsaw to fix a leak

 

[andrethegiant70]

Yeah, baby, nice work! My favorite saws are the one's that I brought back from the dead. Now go run the poo out of it.

 

[coryj]

I like the idea of putting a bandaid on a chainsaw to fix a leak

I was hoping someone would pick up on this, I thought it was kind of funny. Putting a bandaid on a chainsaw "wound".

 

[svk]

Keep us updated on how it works. If it doesn't you aren't out much!

 

[coryj]

RTV'ed in place for an oil proof seal.



Layer of JB weld over the whole deal. I scored the plastic lightly with a utility knife so it could adhere.

Test fit the muffler to check clearance and we're good to go. She'll cure until Thursday morning and then I'm going to cut some wood.

Next I'll contact Husqvarna and get the ball rolling on discussions about offering this customization on a few saws each year as a factory option. It's apparent they under-engineer their saws.

Don't worry AS members will be able to have this customization done on their saws too. Maybe a group buy at a discounted rate.