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New Water Pump Worked, Then Stopped!!!!

M

Mako236@WYC

New member
I just installed a new Honda water pump kit and OEM thermostat in my BF 40A.

With ear muffs on and the cav plate intake taped off, I ran the engine for 10 minutes with a steady, strong discharge from the water tell-tale. I stopped the motor. When I restarted it 30 seconds later, there was no stream from the tell-tale and it smelled like the impeller was burning. I stopped the motor, pulled the thermostat (looked perfect), pulled the hose off the tell-tale and blew into the hose. It was clear. The intake screens are clean and there is plenty of water flow through the ear muffs.

When I had the gear case off, I flushed water down through the thermostat housing and it freely flowed out the bottom of the middle unit.

Any suggestions what the issue is? Should I pull the gear case and inspect the impeller? Try again with the thermostat out?

I've done this maintenance many times and never had this issue.

Thanks for your help!
 
Since you smelled the impeller I definitely would pull the gearcase and check it.

It's possible that you didn't get a good seal and she sucked air losing prime (one reason I don't care for muffs).
Or, something else may have happened, like the drive key jumped out or fell over.

Good luck.
 
Gentlemen, Thanks very much for your suggestions.

I pulled the gear case and disassembled the water pump. The impeller was was intact but it had clearly overheated, burning the gasket under the plate, near the shaft. Hopefully that did not compromise seals below. I'll know for sure next time I change the gear oil (after running for a few hours). After inspecting the water pump components, I changed the gasket and impeller.

I'm 99% sure the cause was failed water supply from the muffs, as jgmo suggested. This is the last time I take that short cut!

Using a Brute trash can (my usual procedure - just got lazy last night), it's pumping strong.

As many have commented, many times, DO NOT TRUST EAR MUFFS, USE A PROPER CONTAINER AND CLOSELY WATCH YOUR WATER SUPPLY!

Thanks again for taking the time to respond.
 
Nothing wrong with muffs, just use the right size, in most cases they are too big and leak badly. The small round ones work fine on those little motors.
 
Best thing about this is that you figured it out and got it fixed with no lingering doubt about a "mystery fail".

I used to like muffs until I didn't.

Don't own any now but....for guys that do shop repairs... they're probably an essential tool to keep production up.

For us "one at a timers" my opinion is the test tank makes the most sense for evaluating the outboard and effective flushing.

Glad you GOT 'ER DONE!
 
Gents, great advice here that will hopefully save many headaches for folks. Thank you all very much.

From my perspective, tank testing is the safest route and most accurate method for two reasons with this particular motor: 1) as long as the lower cavitation plate is submerged, water will be supplied from all three points of ingress (third intake port under plate, right above the prop), just as is the case when afloat and operating. 2) if muffs are properly fit and sealed, the influent water pressure (whatever your hose is supplying), is "helping" the water pump to move water.

The tank method is certainly more work and not always practical so the moral of this story for me is: if you use muffs, use properly sized muffs, be sure they are securely placed and keep a close eye on them and the water supply to them when running the engine.

Thanks again!
 
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