Riser?

[dissturbbed]

I always hear people talk about the riser that is connected to the manifold what about the riser that is connected to near the bottom of the engine? does that go bad as well. I am asking because i am also having the high speed overheat problem. Type of boat i have is a 1978 mercruiser 120hp pre alpha

 

[alldodge]

I always hear people talk about the riser that is connected to the manifold what about the riser that is connected to near the bottom of the engine? does that go bad as well. I am asking because i am also having the high speed overheat problem. Type of boat i have is a 1978 mercruiser 120hp pre alpha

:welcome: to iboats

Not sure what you mean by the riser near the bottom of the engine. If your talking about the item 1 in the link below (exhaust elbow), then yes it can it can cause overheat issues. It can cause the issue if the exhaust flapper (item 7) has broken off and is clogging the exhaust port. To check remove the exhaust boot (item 5) and see if the flapper is in place .

http://www.mercruiserparts.com/Show_...ELBOW+ASSEMBLY

 

[Speakrdude]

Wouldn't that be called the "lowers"?
:joyous: