Alpha 1 gen 1 impeller question

[Begester]

Trying to get a little education on a cooling issue I'm chasing. I'm getting water out of the prop but very little (like water fountain level of flow) is getting into the engine. I've replaced the manifolds/risers and had the heat exchanger rebuilt. Still overheating on the muffs and pulled the lower unit tonight. Water is flowing from oil cooler to the hose where the upper and lower lower unit meet, and I verified this with a garden hose.

After pulling the lower unit, I noticed that the water pump has what appears to be a small "burn" and there appears to be a blockage in the line where my hand is pointing in the attached ​​photo. Could this cause some sort of pressure issue that would prevent the impeller from pumping water up into the engine?

 

[Bt Doctur]

Base is damaged , get the full water pump kit

 

[Begester]

Thanks, that's the plan. Would this prevent water from being circulated into the engine? I get flow out of the prop but very little into the engine.

Just trying to make sure there isn't anything else I need to look for before I put it back together.

 

[zellerj]

Look at the upper housing water tube. If the water tube base is also melted, it needs to be replaced. Also there is a pretty sharp turn after the water tube base to direct the water into the bell housing, and bits of old impellers can hide in there. Check to be sure the hose from the bell housing into the transom is not kinked.

Good luck. I just went through this. The procedure in the outdrive manual 6 is what I used to rebuild the pump, and it worked great. You can purchase the Mercruiser outdrive manual from ebay as a PDF file for about $5.

Jim

 

[dubs283]

get the full water pump kit

fyi, the base is sold separate from the water pump kit

 

[Begester]

Thanks for the replies. Zellerj, I ran a garden hose from the inside of the transom and had good flow out of the upper housing water tube. This means I'm good right?

 

[Rick Stephens]

Want to be certain you have the pump working right? Then after you get finished reinstalling it, pull the line off the thermostat housing that comes from transom and point it at a bucket. With muffs running full blast, fire up the motor. Should fill a 5 gallon pail in under 30 seconds.This will prove you have a good pump, that there are no blockages between said pump and motor at places like the oil cooler, if you have one, or the water pocket.