testing water pump mercruiser pre-alpha

[acarleson]

Hello,
I have an old mercruiser prealpha and I'm booting it back up after winter storage. I want to test the water pump but I can't find clear directions in my manual. My outdrive is a prealpha and my motor is an old (60's) GM 165. How can I test to see if water pump is working? I was hoping there would be something like a telltale on outboards but I'm not seeing anything. Sorry if this is a dumb question, I just can't find the answer anywhere! Thank you all

 

[Bondo]

Ayuh,..... How long has it been since you replaced the impeller in the drive,..??
If more than 2 years,.... It's time to replace it again,.....

 

[acarleson]

Hi Bondo, thanks. It's only been a little over a year, but this was the first year I didn't use it all year (COVID) so I'm thinking it's worth a test. Maybe I'll just replace to be safe this year, but I still feel like it's useful knowing how to test Thanks!

 

[Bondo]

Ayuh,..... 'bout the only "Test" is to pull the hose from the outdrive off the t-stat housin', direct it into a bucket, 'n time it to see the volume it moves,....

The fins on the impellers take a set with time, especially when not run often,....
They stay bent, insteada flexin', 'n won't properly pump water,....
I recommend ya service the pump, this year,....

 

[acarleson]

Hi bondo, your point is well taken. I'm glad to know how to test, but I'll just replace the whole pump just to be safe... cheap insurance. Thanks!