1977 Mercury 850 Cooling at high speeds

[smara04]

At idle and low speeds I have water coming out of the little hole on the side of the motor so it is cooling fine.

When I plane out and start cruising no water at all. Right when i slow down steam starts shooting out of the hole, then in about 10 sec here comes the water again.

I need to know what to look at first before i start tearing into this motor. Please Help Im confused!!!

 

[Laddies]

Re: 1977 Mercury 850 Cooling at high speeds

Either the plastic pickup plates are distorted or the most likely thing is there is junk (impeller pieces) inside the cover plates or a exhaust leak on the pickup side of the pump, bad gasket or crack in the pick up or lower pump housing.

 

[smara04]

Re: 1977 Mercury 850 Cooling at high speeds

replaced impeller cools like a champ now Thanks!!