Cooling issues

[Aaron Lariscy]

I have a 1974 7.5 Mercury I have the water pump working well, I can take the tube out of the drive shaft housing and stick it in the water pump and run it with a drill and it pumps great. I still am not getting a steady flow from my hole. It's flowing just intermittently in spirts. Where else could I be loosing water at? I was thinking maybe the gasket between the driveshaft housing and head might be bad or possibly a head gasket What do yall think?

 

[crazymanme2]

Sounds like some obstruction.With your lower off try to push water with a hose through motor & see if its a steady stream of water.Make sure your lining up the water tube when putting lower back on.

 

[Aaron Lariscy]

Ok played with it some more today and found out some more strange things. With the foot off I squirted water in the water outlet and water came out in two places inside the gear housing. It comes out of the inlet tube and it also comes out someplace around the power head. I pulled the power head off and it had a crappy silicone job and no gasket. I cleaned up everything real nice and used RTV to reseal it. At the moment it is drying but I don't think it has solved the problem, I blew in the outlet while covering the inlet with my finger and air is still escaping somewhere. The next step will be to get a gasket, maybe it has to blank some passage off that I can't get with RTV if that don't fix it I am at a loss.

FWIW I am pretty sure it is not any of the usual issues I have searched and already checked all the normal venues.

 

[RBuffordTJ]

Sounds like you are on the right track, keep looking for more leaks before the port where the tell-tale hose is. If that motor has a thermostat (it should) you might consider pulling it and back flushing your block with the lower unit off and a clean bucket under the pick up tube, you would be surprised what can be sucked up there and lodge. If it has overheated, replace the thermostat anyway just to be safe.

Did you ever have the old impeller come apart and tear the fins off? If that has happened inthe past it may have a chunck up there in a passage that needs to be removed. Could have happened to the previous owner, and this type of issue can give a constant overheat issue to a intermittant as it shifts.

Bufford