Exhaust Flappers J-Pipe Mercruiser 3.0 Worn?

[StinkinRenken85]

Hello Iboats experts! I just got a used J pipe in the mail today for my 85 mercruiser 3.0 with Exhaust flappers installed. The flappers still have their rubber but don't snap shut the way I thought they would...I ran a hose into the pipe with the top of the pipe upside down to see if the flappers would stop the water. Water came out of the pipe and out of the 2 rubber squares that hold the flappers on. When I pushed on the flappers to open them up more water came out so it does seem that the flappers slowed down the flow of water but didn't stop it all by any means...did this test show me anything or would the flappers only work when the pipe is vertical and completely filled with water? or should I just order some new flappers?

 

[harringtondav]

I just checked shutters and grommets for your '85. $23-$33 depending on Merc. or Sierra. Don't expect your shutters to seal completely. They are working against cast aluminum surfaces which aren't perfect. Their design intent is to block most of the backwash from a sudden throttle down from entering your exhaust manifold. Spend the few $$ and feel safe. Good luck.

 

[StinkinRenken85]

Ok thanks for the answer I think I will take your advice and pick up the new parts but now if the new ones don't seal completely I wont think I installed them wrong or they are defective. Thanks again.