Sloppy muffler bolts on Tecumseh 2-cycle...

[Touring5]

Today as I was preparing to put away my Toro CCR 2400 CTS snowblower I noticed that the muffler was very loose. As I had had the same issue 4 years ago I took the shroud off and saw that both muffler bolts were loose and the gasket was in two pieces and lying on the interior of the housing. Last time this happened I replaced the muffler gasket and re-tightened the bolts (with a little loctite threalock). At that time I noticed that one of the bolts was a little sloppy in the engine (I guessed that when it ran with the gasket gone & loosened bolts they got galled a bit).

This blower uses a Tecumseh HSK8508312 2-cycle engine and I am ordering another gasket, but I suspect the threads on the engine are not real good. The threads on the bolt look fine, of course. Any suggestions on how to make sure they stay tight? An effective & economical solution is preferred since this blower & engine are approaching 20 years old and I would do the repair myself.

 

[Donald]

Often exhaust bolts stretch. I would tighten just after use when its still very hot. After a new gasket.

 

[JTK]

Exhaust fasteners on OPE can throw you for a loop for sure. I remember thinking something was about to grenade on my Cub Z-Force ZTR, when it was nothing more than the little outlet pipe on the exhaust rattling. All that held it on was a single tiny sheet metal screw. I wound-up grinding a notch in the pipe and cinching it on tight to the muffler outlet with a stainless hose-camp.

 

[old1]

I would also suggest tightening often, but I think doing them cold is better. Threads in aluminum blocks get kinda soft when HOT!

 

[Hokiefyd]

Are you using the correct exhaust shoulder bolts? These have the smooth flange down most of the length that prevents you from over-tightening and squeezing the muffler. If they're not the correct shoulder bolts, the muffler can deform when hot and rattle.

Most also have the locking retainer tabs that help prevent the bolts themselves from backing out.

 

[Pop_Rivit]

Is the the bolt or the thread in the head that's sloppy? If it's the thread in the head just drill and tap it. If it's the bolt then replace it.

 

[Shannow]

Replaced mine with studs that I made from allthread then double nutted...problem solved.

 

[Merkava_4]

It's time for Helicoils. Keenserts are even better if you got enough meat around the holes.

 

[440Magnum]

Originally Posted By: Hokiefyd
Are you using the correct exhaust shoulder bolts? These have the smooth flange down most of the length that prevents you from over-tightening and squeezing the muffler. If they're not the correct shoulder bolts, the muffler can deform when hot and rattle.

Most also have the locking retainer tabs that help prevent the bolts themselves from backing out.


I was going to mention that as well. The retainer has tabs that you bend up beside a flat on each bolt and acts like poor-man's safety wire, preventing the bolts from turning even if they loosen.

 

[Touring5]

Interesting mention of the retainer - I may have seen those on B&S engines, but this (Tecumseh) didn't come with anything like that. It is a muffler with two 5/16-18x3.75 shoulder bolts (original part). The bolts look OK but I ordered two new ones just as insurance. One of the threaded holes looks good, the other one has a much looser fit and shows definite wear on the threads. I have a tap for that size and may use it, and looked into a helicoil - much cheaper than taking it to the shop.

In case anyone is interested, this link shows a diagram of the engine:

Exploded view

Thanks to all for the info & replies.

 

[Lapham3]

I also go with studs on iffy deals like this-then the 'working' area is the nut/stud rather than a bolt into an expensive and more difficult part. I will do this proactively where experience has shown a likely situation like this may occur-good luck

 

[ATS-V]

If you want a poor mans fix you can insert some thin braided wire in the hole (copper or aluminum speaker wire) and reinsert bolt. It doesn't take much to take up the slop.

 

[Oldmoparguy1]

If, IF, you have room for studs, get studs with matching threads for the engine end, with fine threads for the outer end. Use steel filled JB-Weld to mount the studs in the block, use flanged locking nuts on the outer end.