MCM 165 Seawater intake problem

[John_B]

Over the winter, I had the boat serviced and the Water Pump was replaced. First few outings on the lake were fine. Last weekend I broke down on the water after stalling at idle and then over heating. I took apart the lower unit, replaced the Impellor that had broken fins. Everything seemed fine, running at home with hose. After about 45 minutes the boat started over heating and I noticed it leaking at the weep hole.

I assume I damaged the water pump, (Waiting on a pulley puller to pull the main pulley), but while waiting, I decided to run through the hoses and see if I can find any pieces blocking the hose. I noticed that it comes in the back via a 90 degree elbow, then goes into voltage regulator before ending at the heat exchanger.

My question is where might I expect to find pieces stuck and how would I examine the elbow that goes into the stern drive?

Also, is it cooling the voltage regulator or something? Never seen water pipes going through something like that?

 

[Eric 3.7LX Alpha 1]

Yes the VR is water cooled. There's a good chance you blew the head gasket with an over heat with the block being aluminum and cast head, and different expansion rates. The engine water pump is not like an automotive one you have in mind. It is an impeller bolted to the end of the camshaft. Here is a write up on the weep hole leak: https://www.sterndrives.com/470information/470coolantleakrepair.html

There were two sizes of heat exchangers on these engines an earlier 3" diameter and later upgraded to 4".

 

[jhamblett]

Sorry, but it's time to sleeve the cam shaft with a spedi sleeve . You might get lucky with the head gasket.99087 part number. Heat the sleeve with a hair dryer and use freeze can spray on the cam nose

 

[John_B]

Sorry, but it's time to sleeve the cam shaft with a spedi sleeve . You might get lucky with the head gasket.99087 part number. Heat the sleeve with a hair dryer and use freeze can spray on the cam nose

Well, after replacing the Impellor, It ran fine, and didn't overheat, but was leaking from the weep hole. I have new seals and gaskets, but the cam shaft appears fine. So far as I can tell, head gasket didn't blow.

 

[jhamblett]

Your 1 seal away from getting coolant into the oil. It doesn't take long to re sleeve

 

[Eric 3.7LX Alpha 1]

Well, after replacing the Impellor, It ran fine, and didn't overheat, but was leaking from the weep hole. I have new seals and gaskets, but the cam shaft appears fine. So far as I can tell, head gasket didn't blow.

What do you mean when you say the camshaft appears fine? I'm not sure how you can tell until you take it apart.

If your leaking from the weep hole, the 1st seal on that cover that the camshaft rides on is leaking by. The engine circulation impeller doesn't usually get worn out, the rubber seal and the surface of the camshaft that the seal rides on gets worn out, causing the weep hole to leak to warn you. You may get lucky and a new seals stop the leak. I tried it and had to get the speedi sleeves. There are two required because one isn't big enough to cover both seals.

 

[John_B]

Your 1 seal away from getting coolant into the oil. It doesn't take long to re sleeve

Where do I find a Speedi Sleeve? I haven't replaced the seals yet. My mechanic is who said the cam shaft is fine.

 

[kenny nunez]

Speedi Sleeves usually can be found at a bearing supply store. NAPA may be another source plus on the internet.

 

[jhamblett]

Where do I find a Speedi Sleeve? I haven't replaced the seals yet. My mechanic is who said the cam shaft is fine.

Amazon.com