Stuck Serpentine Belt

[Legend]

I have a 18ft Donzi Classi with a 350 MPI Horizon. I had not used the boat for about two months. I tried to start her on the weekend and she started on the first crank however, the serpentine belt would not move. I immediately shut her down. My initial thought was that the water pump was gone and frozen. I did not leave the engine running long enough to see if the other pullys were rotating. Any input would be greatly appreciated.

[Barry Eller]

Poodle is correct.

However, does it have a belt tensioner or idler pully or powersteering pump?

[ky-donzi]

Take the belt off, and check all the accessories. They all should turn by hand easily. Which every one doesn't turn is the fault

[MOP]

I have had seen many a near new water pump stick after a layup, if the internals are fairly recent break it loose and check it for good water flow. It is very common on boats that did not have anti freeze run through the system likw we do up north, the anti freeze is very lubricios and keeps the rubber from sticking to the pumps housing.

Phil

[RedDog]

Happened to me when my seawater pump impeller destructed.

The belt was smoking in short order. Had to replace the belt and the pump housing / backing plate / impeller (there is a kit)

[Legend]

The water pump is tight and difficult to turn. The engine has a total of 26 hrs on it and this is the second water pump I would had to replace. Is this normal?

[BUIZILLA]

i'm assuming you have an Alpha drive here ??

what year is the boat ??

[Ranman]

The engine mounted seawater pumps are hard to turn by hand, but it is possible. On my 18 (350MAG/Bravo) the engine will sometimes rotate backwards a bit upon shutdown. This has caused the vanes on the seawater pump to invert themselves. On the next startup the belt doesn't have enough grip on the pully to flip them back the right way and gets stuck as you describe. In these situations, I have removed the belt, cranked the seawater pump by hand enough to flip the vanes back to the right direction, reinstalled the belt and went on my merry way.

I have since learned that a little more belt tension will automatically solve this issue at the next startup. I set the tension so there is enough grip to flip the vanes should the engine spin backwards a bit at shutdown.

You should not have to replace your seawater pump but every 100 hours or so unless you run it dry or pick up and send a lot of sand through it.