Mercury 500 Thunderbolt 50, cooling system

[kingleonidasll]

Hello everybody, first post here and I've got a question about my first boat engine. It's a Mercury 500 Thunderbolt 50hp, year unknown, serial #7053248. Bought it last month, and the previous owner sold it to me saying he thought the impeller was no good. I'm halfways thinking I might be missing a gasket somewhere, but let me tell you about my troubleshooting first.

I took the leg off and opened up the impeller housing, all seems good in there. I even put it in a bucket of water and spun the driveshaft with a drill to test it. All checks out.

When I try to start the engine with muffs on, no water comes out of the telltale. I've poured water through the telltale hose, and water comes out of the bottom of the engine, so I don't believe the internals are clogged. I even blew both the copper line that goes to the impeller housing and the telltale hose out with an air compressor.

I'm wondering if somewhere in the cooling system there's a gasket missing. Specifically, should there be something between the copper cooling line and the impeller housing? Right now it's just copper line ---> plastic impeller housing. In my mind, that's not a recipe for a good seal?

Please let me know your thoughts!

 

[GA_Boater]

Welcome aboard.

Where the water tube goes into the impeller housing, two things seal the tube to the housing. A guide, #28 and a cup washer. #29. I would replace the impeller with a kit which includes both parts. You have no idea how old the rubber impeller is and they harden and become brittle over time. 2-3 years is the life of an impeller.

A full OEM kit is Quicksilver 46-77177A3, Sierra kit is 18-3324

 

[kingleonidasll]

Thank you very much!! I'll bet that there is exactly what I need!