Muffler shot?
#4

Joined: Dec 2001
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From: Summerfield,
NC
ORIGINAL: Tired Old Man
If it was mine it would get replaced. I'd also check the run out of the prop/crankshaft.
If it was mine it would get replaced. I'd also check the run out of the prop/crankshaft.
#6
Thread Starter

Checking the crankshaft runout is an interesting suggestion. I've had this engine (Brison 3.2) for about 5 years or so with the same muffler and have no problems until recently. Several weeks ago the muffler vibrated loose (first and only time) and I secured it with red loctite and fresh ultra copper RTV. The engine has never been in a crash or had a prop strike of any kind (at least since I've owned it). The only variable is that I recently fitted a carbon fiber spinner to it purchased through EBAY. It was a very inexpensive single bolt unit but looks of decent quality and the price was right ($27.00). I've noticed an ever so slight out of round looking wobble with the spinner at low RPM. Almost like the hole in the backplate is not perfectly centered or the backplate is not perfectly round. It appears to run true at mid and high RPM. I have to admit that I didn't balance the spinner as I don't have a decent balancing setup for spinners( I only have a small hand held balancer for props) and I've always used factory cut Tru-Turns in the past and they seem to be perfect "out of the box" (bag). My guess is the cheap spinner is causing the vibration resulting in the destruction of the muffler. Same final result as a bent crankshaft could cause as Pat suggested...




