Replace exhaust shutters (flappers)

[matty133]

Hello All,
I am the proud owner of a new-to-me conquest 3250. I would first like to say thing site is great and thank you in advance.

I have twin mercruiser 350's with Alpha MR's. 1981

To the problem:

1) shutter valves are gone and need replacing. I have been told I need to pull the motors to get at them since they are in the lower y pipe. Is this true? Is there anyway to replace them from the outdrive side since I will be pulling that anyways?

2) Is there anyway to retrofit a shutter near the top of the tube?

3) Are the shutters necessary? Some say yes, others say no. The boat will be run in the ocean off the coast of Maine.

Thanks
Matt

 

[Haut Medoc]

Re: Replace exhaust shutters (flappers)

Hello All,
I am the proud owner of a new-to-me conquest 3250. I would first like to say thing site is great and thank you in advance.

I have twin mercruiser 350's with Alpha MR's. 1981

To the problem:

1) shutter valves are gone and need replacing. I have been told I need to pull the motors to get at them since they are in the lower y pipe.
If they are in the lower y pipe, you must pull the engine for access, I'm not quite sure when Merc. went from lower pipe shutters to uppers, but it was around that time, if you have log style manifolds as opposed to center rise manifolds, I would think they are in the lower....
Is this true? Is there anyway to replace them from the outdrive side since I will be pulling that anyways?
No, in either case....

2) Is there anyway to retrofit a shutter near the top of the tube?
Probably, but you will need to pull the risers & drill a hole for the receiving pin through the upper y pipe, you will need to research if there is an after market shutter though.....
Also, will you have the room to drill this on a twin set up?......

3) Are the shutters necessary? Some say yes, others say no. The boat will be run in the ocean off the coast of Maine.

Thanks
Matt

Answer #3 will depend on the specific static water level of your boat & your boating habits.....
If you shut down & drift frequently, I would say you would benefit from having them installed, since the North Atlantic can get rough......
If you are a never shut it down kind of guy, I would say you would be OK without them.....
Hope this helps......

 

[whywhyzed]

Re: Replace exhaust shutters (flappers)

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[Haut Medoc]

Re: Replace exhaust shutters (flappers)

I changed a shutter on an inline Merc by just taking the riser off - didn't pull the engine...the shutter is at the top of the pipe - just drilled the rivets and popped new stainless rivets to reinstall...cant see why this would be any different on V8

It (they) are 1981 V 8's.....
It can be very different.....