351 mercruiser FWC hose plumbing engine overheating

[rabristol]

1974 FWC inboard. I am tracking down a heating problem at WOT and noticed the hose coming out of the thermostat housing goes to the back of the manifold. On the cooling schematic it shows the hose should go from the thermostat housing to the front of the manifold and the hose from the backof the manifold should go to the heat exchanger. Could this have an effect on engine temperature? The engine is fresh water cooled

 

[ENSIGN]

Re: 351 mercruiser FWC hose plumbing engine overheating

It should not matter which way the water is flowing through the manifold.Check the impeller first.

 

[Don S]

Re: 351 mercruiser FWC hose plumbing engine overheating

Was it working ok for a while then just started having the overheating problem?

If those two are in the wrong place, what else is wrong. Might want to post some pictures of your hose routing and thermostat housing.

 

[rabristol]

Re: 351 mercruiser FWC hose plumbing engine overheating

There is a bypass hose that I do not have as I saw a schematic and it had this hose. In the photo I removed the plug in the water circulator pump and put a red arrow on the place where the schematic shows a hose to be connected from the pump to the thermostat housing. I spoke to my local dealer and his drawing didn't have a hose for that part? Does anyone know what the benefit of having the hose installed there is???? Always overheated with the new long block I installed.