Manifold and Risers

[JMC69871]

I am going to be pulling the risers tomorrow to inspect them on my OMC 5.7 Cobra. One of the risers is leaking at the manifold/riser joint gasket. It has a 1/2 cooling system by San Juan Engineering. Is there any hints or tips anyone has to offer before I tear into this? Do I have to drain the manifolds or anything? Any help would be appreciated. Thanks!

 

[floridaboater1]

Re: Manifold and Risers

You will want to drain the block. If you can see a leak at the riser gasket then it is probably leaking inside too. When this happends water leaks down your exhaust manifold on to your pistons and THIS CAN CAUSE YOU TO HYDROLOCK THE ENGINE. Pull the risers then pull the plugs on the side of the riser look inside for rust or pitting the walls in the riser should be smooth. If there is pitting they need to be replaced. Look at the cast iron around the gasket area it should be smooth if there is pitting you wont get a good seal and the risers need to be replaced. Hope this helps

 

[jerryjerry05]

Re: Manifold and Risers

What year???Fill out the profile(you too Flboater)salt or fresh water?It could be just a gasket.But do drain it as you don't need it to go into the motor.J