Water Pump

[rwood13]

I fixed my water pump (202M3) today after starting my engine yesterday and seeing no water coming out of the exhaust. One of the impeller's fins had broken off and lodged in the outlet port. Fortunately there was a spare impeller on board and after installing it the system worked as before (water coming out the back and temp fluctuating between 140 and 180). The shaft wasn't scored and went in easily and doesn't seem to wobble.

Tonight I ordered the manual and a spare impeller. Is there anything more I should do to keep the pump going? And what does the cam do?

Thanks to this site, this beginner had a rough idea to look for.

[Don Moyer]

Hello rwood13,

Your pump should be OK given the minimal amount of play between the shaft and the housing. Don't forget to turn the grease cup in approximately one turn every 8 to 10 hours. You can use any good general purpose grease from your local auto parts store that includes wheel bearings on boat trailers.


The cam is the component which makes the pump a pump. As the lobes of the impeller flex over the cam (hence the name "flexible impeller"), it creates a pressure gradient which draws water in through the intake port and discharges it through the outlet of the pump. Without the cam shoe, the inside of the impeller chamber is perfectly symmetrical and the rotation of the impeller would do nothing but move water around and around within the impeller chamber.

You might want to remove the thermostat and soak it in vinegar for a day or two. The fact that your temperature moves all the way to 180 (at which point it closes the by-pass loop) suggests that it might be a bit sticky.

Don

[rwood13]

Thanks for the explication, Don. Now it all makes sense. Thanks, too, for the reassurance that the repair should hold, the reminder to turn the grease cup and the advice to soak the thermostat. I've signed up for the 11/12 workshop and look forward to an enlightening day.

[Don Moyer]

Great, we're looking forward to meeting you. I always have to be careful how I say this, but next to spending quality time with Brenda, kids, grandkids, close-in friends, and our dogs, I can't think of anything I enjoy more than spending a day in the company of the Atomic 4 enthusiasts that attend our workshops.

Don