Replacing bellows on a Mercruiser alpha 1 sterndrive?

[Duncan McCallum]

I noticed this summer that my exhaust bellow is cracked and had planned to change it in the fall when I winterize.
Recently I had to drop the gear housing to get the skegg welded after hitting an unmarked shoal. Then I notice two things:
1. A plastic cup like shroud around the water pipe going up the water pump is melted:


2. As is something made out of to semi-circle pices of metal and rubber in between. This last picece fell out of the exhaust manifold above the water pump. The white plastic water dam is fine and in place.
Any idea what these are?

 

[Bondo]

Re: Replacing bellows on a Mercruiser alpha 1 sterndrive?

I noticed this summer that my exhaust bellow is cracked and had planned to change it in the fall when I winterize.
Recently I had to drop the gear housing to get the skegg welded after hitting an unmarked shoal. Then I notice two things:
1. A plastic cup like shroud around the water pipe going up the water pump is melted:
View attachment 167782

2. As is something made out of to semi-circle pices of metal and rubber in between. This last picece fell out of the exhaust manifold above the water pump. The white plastic water dam is fine and in place.
Any idea what these are?
View attachment 167783

Ayuh,.... Welcome Aboard,... #1, is the remnants of the water tube, 'n guide tube,...

#2 is the remains of a shutter,...

My guess is, that motor was run without water flow....

 

[AviatorJim]

Re: Replacing bellows on a Mercruiser alpha 1 sterndrive?

I have to concur with Bond-o. The shutter is inside the boat, in the tube that rises up from the transom assembly to mate up with the exhast manifold. You'll be pulling the engine out to repair it, and there are a lot of boats running around without it (like both of my boats). The water tubes and sleeve belong right where you found them. From the looks of it they melted from hot exhaust, caused by a loss of cooling water. If it happened when the engine was run out of the water without the muffs, then you also probably need a new impeller, and a fair chance you need to replace the upper and lower impeller housing. But that is an easy job while you have the drive split to repair the skeg. Make sure you twist the impeller the right way.
--Jim