Cracked Muffler - Lean Burn?

[StihlNAlberta]

Just wanted to collect some thoughts. I have an older Stihl saw with about a 1" hairline crack on the muffler neck where it welds on to the actual muffler itself. Looks like the factory weld had given out over time do to vibration and usage.

It really is quite small.

Since I'm not a tig welder, and a new muf. Is around 125.00, do you think it would've safe to run? I don't want to create a lean burn scenario and sieze the top end .... Am I being over cautious?

Thx.

 

[MrGiggles]

You will want to have it fixed sooner rather than later.. The vibration will make a small crack into a big one pretty quickly.

 

[Moparmyway]

If you dont fix it, at least stop drill it at the ends of the crack so it is less likely to spread

 

[half_full]

Kinda off topic but kinda not. I know to drill ends. But, of the two welders I have what would be best fix - MIG wire feed flux core or oxy/acet? Brazing rod?
I have welded a muffler with the MIG but it took a while to cover the burn through's

 

[jughead500]

I do pretty good with map gas and brazing rod.blew the whole front cover off of my ms360 the other day.loud as hades but finished a few cuts and enjoyed the music.

 

[Moparmyway]

Kinda off topic but kinda not. I know to drill ends. But, of the two welders I have what would be best fix - MIG wire feed flux core or oxy/acet? Brazing rod?
I have welded a muffler with the MIG but it took a while to cover the burn through's

What size wire on the flux core ?
The smallest diameter (.030) might be too hot.
I have used .023 with C-25 on thin stuff, but use the TIG on mufflers

 

[Big_Wood]

Kinda off topic but kinda not. I know to drill ends. But, of the two welders I have what would be best fix - MIG wire feed flux core or oxy/acet? Brazing rod?
I have welded a muffler with the MIG but it took a while to cover the burn through's

it all depends on your welder. i got a lincoln 175T which i like cause i can turn it right up to weld real thick or way down the weld thin. with mine i put it on it's second lowest setting and do quick spot welds one after another. on the lowest setting it doesn't penetrate fast enough for the quick hits of the trigger. after every spot weld there will be a pin hole in the center of the weld. every following weld i start at the pin hole of the last one. it actually looks pretty decent by the time i'm done and i never burn through. it's all about how you adjust your welder and handle your trigger. all welders are different though. i use argon/C25 mix but have used the flux core wire and find it to be harder.

 

[Saw Dr.]

If it is an 041, cracked mufflers are VERY common. You should be able to pick one up for alot less than $125. About the only ones I'd bother welding on are 090G and 084 and that is because they are very difficult to find.

 

[o8f150]

a vibrator will make a small crack into a big one pretty quickly.

yep... my x wife knows all about that after I divorced her,,, and here she wanted me back

 

[Moparmyway]

yep... my x wife knows all about that after I divorced her,,, and here she wanted me back

 

[woodguy105]

Did my 361 muffler with a mig. 035 flux core. After Burning thru I had a 1/4 inch hole, I ended up fitting a small piece of heavier gauge sheet metal over the hole and spot welded till sealed.

 

[StihlNAlberta]

Thanks for the info. I have a fair bit of welding experience with my Miller but not on anything so thin, and do not have the tig attachment unfortunately. It's an old 076 I'm trying to finish off so it's reliable. Maybe keep my eyes peeled on eBay or give it to a buddy of mine who is a welder for the government. I hate to throw on JB weld or a patch cuz it will likely just fall off ... Some of the used parts for these seem to be getting more expensive and the OEM stuff is gettin discontinued. I gotta figure out how to braze or tig I suppose. Cheers

 

[StihlNAlberta]

I know a torn rubber intake boot would be much more detrimental to a lean seizure than a hair fracture in the muffler would, but it's nice to have everything tip top.

 

[MrGiggles]

I don't think you really have to worry about that too much.. It's more of a "do a little work now to save a lot of work later" situation... I'm sure you could run it as it is now until it flies apart with no harm to the engine, but by that time the muffler will be cracked and fatigued so bad you'll more than likely have to replace it.

I have done a couple just with regular MIG wire and CO2 gas.. I forget what size but I use a 110v Lincoln on the second to lowest setting, using the tack, stop, tack method. I won't burn through this way.