i have a 75 mach1 with a 454. my exhaust is the log type manifols that go thru the transom. ever since i put a new intake manifold on it the rubber flaps that go over my exhaust keep ripping. is their a way to solve this because i hate buying new flaps every single time i go out. before the new intake manifold was put in it never ripped the exhaust flaps. what could be the problem!!! please help!!!!thanx
mach1 454
The only thing I can think of right off the top of my head is that the new manifold changed your air/fuel mixture at the combustion chamber resulting in a leaner/hotter burn. This heat is what is causing your flappers to burn. Do a plug check right after a WOT run to see what the air/fuel ratio looks like and go from there.
Good luck,
Chris
Usually this is the result from improper cooling. The engine cooling water is what keeps the flap from melting off of the center pin it is attached to. If you start the boat out of the water at all, it can happen in seconds like that, and if you have changed the cooling route to reduce the flow to the engine, that will do it too. Either way, you need more water to the exhaust manifolds.
If you figure your running the right temp and water flow seems ok you might think about ditching the old bells all together and going with some stainless tip's with the anti-burn flap. They are not cheap, I think about 75.00 apiece but they work great and look bitch'n too http://free.***boat.net/ubb/biggrin.gif
Mach 1, are your flappers mounted inside the bell/trumpet or outside with a hose clamp? If they are mounted "inside" with a small metal plate and two screws try this. When removing the plate for flapper replacement, save the small chunk of rubber underneath it and remount the piece of rubber and plate on top of the new flapper. This has helped me extend the flapper life.
Posting Permissions
Reply With Quote