Yes I said it, muffler bearings!
Greetings From the workshop of the ol' Snoopster, where I have taken up the slow, and very painstaking process of breaking in a Fox 35 stunt.
I mounted the engine in my trusty old Tatone test stand (with the pieces of wood under the not-so-level mounting lugs) and proceeded with the run-in. There has been much debate and everyone has their own methods about that part, so I won't go into detail, except to say we made lots of thick castor oil smoke.
I did however, find that mounting the muffler and tightening the mounting screws sufficient enough to make sure it stayed part of the engine to be a challenge.
If I tightened the muffler screws much tighter than finger tight, the engine would not turn over. And I mean not turn over, at all.
There was a very fine line of snug where the engine would run and the muffler didn't rattle loose on the test stand, and too tight to turn over. I have ran the Fox 35 stunt in many applications over the years, but never with a muffler.
I can only imagine that there are others who have dealt with this before, and I am sure there is other methods of remedy, but here is mine.
Muffler bearings! I took two short pieces of aluminum tubing I had laying around, and carefully cut them to fit in the space between the muffler, and the mounting lugs on the side of the engine case. Then I filed a flat along one side. After a bit of time hand fitting the new muffler bearings, they provided a solid mount, without distorting the engine case.
The muffler never once shook loose on the test stand, and the break in continued.
This page was upated July 17, 2012