Water pump leak

[Bryanbt]

(first time boat owner anxiety setting in...)

As I was doing my end of season oil change, I noticed drops of water dripping off the engine block below the water pump (below and towards the engine centreline on the flat area just forward of the shifting lever base). The water flowed even after the engine is turned off.

I can not see the source of the leak. I have looked all around the water pump (Oberdorfer on a 1971 late model engine #175709) and can not see any signs of the leak. I have strategically placed bits of shop towels in various areas in contact with the water pump and left them in place for over an hour. All were dry. Yet two large shop towels placed below and forward of the area are fully soaked overnight.

What are the most likely sources of such a leak? I am very concerned about getting this fixed before winter as I fear all my antifreeze will drain out if this is not fixed. And I am scheduled to haul out at the end of the week.

I have looked for other sources, such as the aft drain block, but everywhere else seems dry.

The flow is uneven and seemed much less tonight than when I first noticed it two days ago. I wonder if my playing around with the grease cup may have lessened the flow. There seemed to have been enough grease but I filled the cup with more grease just in case. Could a grease cup with insufficient grease be a source of a leak?

Any suggestions on what to do next would be gratefully received!

[Don Moyer]

Unfortunately, leaks of any kind can "travel" quite some distance before falling into a drip towel, so these towels usually make poor locators of leaks. I suggest you pick up one of the inspection mirrors that are available at most any local auto parts store. They come in various sizes and most have extendable thin handles so they can be placed in rather tight quarters. With practice, you can shine a flashlight on the mirror and illuminate areas that are very dark.

Having said all that, you're probably on the right track to suspect that your leak may be coming from the base of the grease cup, but refilling the cup with grease will be only a short term partial fix. If you can get your new inspection mirror directly under the base of the grease cup you should be able to catch the very origin of your leak (if it is indeed the grease cup). If this is the source of the leak, the whole grease cup should be replaced. The latest grease cups from Oberdorfer have small spring-loaded check valves to prevent water from backing up into the area of the grease.

Don