water shutter assembly question

[toolsinbox]

I am looking at the # 807166A3 Shutters and they dont fully block all the water. There are square holes near the hinge. Can someone explain how these work ? Are they just to stop a large gush of water and the small amount that may get buy is ok?

Thanks

 

[Don S]

Re: water shutter assembly question

They were never meant to fully block all the water, only to stop waves from pushing up to the manifolds. The riser height is what keep water out of the manifolds when just sitting in still water.

 

[ken_23434]

Re: water shutter assembly question

There are 2 rubber pieces that go in those square holes and those 2 rubber pieces then hold the shaft for the flapper. Otherwise, you have a small exhaust leak and water spray in the boat. (experience)

 

[toolsinbox]

Re: water shutter assembly question

Thanks as always Don.
I see..... so the pressure of a big wave, or the wave from a wake when stopping wont blow past these shutters?
Also I see in the manual you have here, where it shows the diagram to measure correct riser hight, you circled it and hand wrote " Wrong". What is the correct riser hight ?

Thanks

 

[toolsinbox]

Re: water shutter assembly question

There are 2 rubber pieces that go in those square holes and those 2 rubber pieces then hold the shaft for the flapper. Otherwise, you have a small exhaust leak and water spray in the boat. (experience)

Those are different shutters

 

[Don S]

Re: water shutter assembly question

Also I see in the manual you have here, where it shows the diagram to measure correct riser hight, you circled it and hand wrote " Wrong". What is the correct riser hight ?

I haven't circled anything and said wrong in any of those manuals.
Which manual, and what page number in that manual so I can have some idea what you are referring to.

 

[toolsinbox]

Re: water shutter assembly question

I am sorry I thought you up loaded the manual.

It is mercruiser manual #9 7A-1 ( pdf page 608)
MCM engines with thro transom exhaust

 

[Don S]

Re: water shutter assembly question

That came from Merc that way. I think the problem was the 15" dimension. All risers are now 13" for IO, inboards or anything.
The older manuals were just scanned from the copy given to the Merc people to scan and may have been changed in later paper manuals. There were no .pdf manuals back then.

 

[toolsinbox]

Re: water shutter assembly question

Thanks for the clarifiication Don. i am sure now that I am well within the 13 inches. I think I am around 16 so all is well.