Temporary Water Pump Seizure only on cold start-up

[Roger Janeway]

My Westerbeke 10-2 behaved well over the first 18 months that I owned my boat, putting in about 80 hours. After a 4-month absence trapped 3000 miles away by pandemic forces, I started her up. There was a great deal of squealing because either the fresh water pump or the raw water pump refused to budge. (The impeller had been changed as part of annual maintenance only 3 months and 9 engine hours earlier and she had worked fine since then.) I tried to manually move the crankshaft, fresh water pump pulley, and the raw water pump pulley but couldn't turn them much. I wiggled the raw water pump pulley back and forth as much as I could thinking that something had corroded inside. (The raw water seacock had been closed during the four month absence.) After a little more squealing, the pulleys relented and let the crankshaft do its thing, the two belts immediately behaved normally, and the engine worked fine for the next hour or so (with several stops and starts). Engine temperature was normal and plenty of water pumped out the stern.

After a two-week break, yesterday I had the same problem starting up the engine: one or both of the water pumps were seized. Again I manipulated the raw water pump pulley as much as I could, back and forth several times, and the engine then started up and ran normally. (I didn't focus on the fresh water pump pulley since I was ignorant of what was what until I came home and consulted the Westerbeke manuals, but since they're all linked by belts one tends to wiggle them simultaneously.) The fresh water cooling system had been drained and the coolant replaced in December after a new heat exchanger was installed.

As part of the recent maintenance, a technician more experienced than I am allegedly checked the belts and pronounced them OK.

I need to go see soon if the problem replicates after only a 2 or 3 day absence, but in the meantime my questions for the forum are:

(1) Should I be able to turn the pulleys on a cold engine manually? In particular, should I be able to turn the small pulley that operates the raw water pump?

(2) Any similar experiences or insights?

(3) Does it make any difference if you use a smooth belt or a notched belt to connect the two water pumps? (I only just noticed this. The original Westerbeke part diagrams show notched belts for both.)

 

[wynkoop]

I suspect actually being able to turn anything attached to belts driven off the motor without opening the decompression valve (if you have one) will be hard as you will be going against the compression of the engine.

I had a different rubber impeller pump, which was electrical driven, behave the same way a few years ago. It was seized so bad the electric motor started to heat and smoke. In my case it turned out the pump refused to turn DRY. Perhaps your belt driven pump dried out and the manual moving got enough water on the vanes to lubricate it?

Plenty of guys with your exact engine that probably have better ideas, but trying to share what I know that might help. So many here have been so helpful to me.