mercruiser 888 runs hot with muffs

[suprahattie]

I bought a 1976 Sea Ray 20srv project boat,I installed new water pump (lower) and have flow through manifolds and risers,but engine runs hot after a few minutes but exhaust manifolds are cool, the thermostat is missing so I ruled that out,I also removed the circulating pump and that looked ok,I can blow through the block unrestricted so I assume thats ok.Is it possible that the engine is not getting enough water to cool both engine and manifolds with the muffs? P.S. I checked the hose routing with a diagram from a previous thread and thats ok.

 

[Blk-n-Blu]

Re: mercruiser 888 runs hot with muffs

You might want to put the thermostst in and re-check

 

[jtybt]

Re: mercruiser 888 runs hot with muffs

Block could be rusted up or rust blockage in the risers.

 

[suprahattie]

Re: mercruiser 888 runs hot with muffs

With the inlet hose to the circulating pump disconnected i can blow through the engine all the way to the risers,I have no trouble blowing the water through the circulating pump into the engine and back out of the thermostat housing a complete loop,from there it gets pushed out the risers.

 

[Saginaw Bay]

Re: mercruiser 888 runs hot with muffs

It needs its thermostat.

The water isnt there long enough to cool the block.