Muffler Issue

[rocklobster]

Hey everyone,

I've had a Husqvarna 350 for about 17 years and it still runs great, but a hole that holds one of the muffler bolts is stripped badly. I can put the bolt in and wiggle it around, can't even see any threads in it. The muffler keeps coming loose and melting the saw.

Before I get desperate enough to try JB Weld, I thought I'd see if there were any better ideas. What would you do?

Thanks.

[lxskllr]

Helicoil or time-cert. I believe time-cert has a better reputation for these applications, but I have no first hand experience.

[DHansen]

Very common problem on the 350.  Don't use JBWeld.  The problem happens when they are not tightened properly.  I always tighten, run engine 10-15 minutes and tighten again hot.  That will prevent the problem from happening again.  As for your thread repairs, repair the threads with an insert as Lxskllr has suggested.  

[DHansen]

Muffler bolts from a 288 Husqvarna are slightly larger in diameter and the correct length.   You can retap to the 288 Diameter and use those 288 muffler bolts.  You will need to slightly enlarge the holes going through the 350 muffler. Still retorque bolt after the engine is hot.  I think its 15-18' Lbs. 

[rocklobster]

Thanks for the ideas! I knew there had to be a better way. I'll see what I can do.

[DHansen]

After about 20 refueling check the bolt tension.  The 350 likes to vibrate the muffler bolts out.  Don't over tighten. 

[Old Greenhorn]

That is a great littel saw and well worth taking care of. I am on my second one and use it a lot for my mushroom logging because it's lite and I have a short (18") bar on it, perfect for what I do, except felling the bigger ones and my 562 is in hand for that.
 Anyway, those saws are notorious for the muffler bolt problem. Fix it right and follow DHansen's suggestions on torqueing. As long as you have that covered and don't have the leaking intake boot issue, that saw will run a long time. I love mine.

[Guydreads]

Haven't weighed in on any conversations here in several months, good to be back. I bought a 350 (Jonsered 2150) whose previous owner/their dealer had installed studs into the cylinder (I think they were 1mm larger threads so the cylinder had to be re-tapped) and then attached the muffler with nuts from the outside. This solution has worked great (The saw is at my other place so I won't see it for a while to be able to get pictures or anything), and I have had 0 issues with the muffler coming undone. I would love to know if they put any thread lock in the holes or exactly what they did, but I doubt I'll ever get the gumption to try and find out as they are pretty well wedged in there. 

[rusticretreater]

I second @Guydreads recommendation.  When you tighten a stud against the bottom of the hole, it adds upward pressure against the threads.  This requires the stud and any pulling forces to overcome the force of that pressure to come loose.  It won't happen.  You could put a bit of JBWeld or Red/Blue thread locker on the studs for a really permanent fix.  Use a lock washer under the nut.

[Old Greenhorn]

Hah! This thread was prophetic. After reading along I kept thinking "Yeah, I should check mine" but I kept forgetting even though I use the saw everyday right now. So today I am out bucking firewood out to the log tumble and the tang muffler flops right off into the chip pile.
 Faster to fix, then the time I spent looking for my locktite. The sockets in my bolts are getting pretty worn and it's getting harder to get them tight.
 All good..... for now.

[donbj]

I just repaired a 2100 cylinder that had a stripped muffler bolt hole. I checked the depth of the hole and found I could tap it deeper by close to a half inch from where it stripped out to. Got longer bolts and good to go. Check maybe you have good metal beyond where the stripped portion is, may get lucky.