RCAnderson
Seaman
- Joined
- Oct 5, 2011
- Messages
- 68
I have a mercruiser 888 with full closed cooling. I would like to add an inboard mounted raw water pump similar to this :
Jabsco Cooling Pumps 43210-0001 - iboats
Can someone tell me approx. how big in diameter the pulley mounted to this has to be to get the correct rpm on the pump ? Not too big and running too slowly, and not to small and running too fast. I suppose faster would be better than slower though. I have an accessory pulley directly on the front of the crankshaft that is 6 inches in diameter.
I am also wondering if I can remove the impellor from the outdrive and leave the housing, and use the raw water intake through the outdrive to provide water to the inlet of the inboard mounted pump.
Will I need a check valve before the pump to prevent raw water draining back when the engine is stopped, then having the pump start dry ?
My reasoning behind all this is that I was on another boat a couple of weeks ago which was equipped with an inboard mounted water pump, and about 40 miles beyond nowhere, the engine overheated and derated itself. Sure enough, it was a blown impellor, which we were able to change while we bobbed around on the ocean. I was thinking later on, and if you lose an impellor in a lower outdrive, there is no way you will be able to change it on the water, even if you do pack a spare. There are not very many beaches in my part of the world, just rocky flat spots, so beaching with the kicker and waiting for a lower tide would not be a very good option.
Anyway, if anyone has any thoughts on this, they would be appreciated.
Ryan
Jabsco Cooling Pumps 43210-0001 - iboats
Can someone tell me approx. how big in diameter the pulley mounted to this has to be to get the correct rpm on the pump ? Not too big and running too slowly, and not to small and running too fast. I suppose faster would be better than slower though. I have an accessory pulley directly on the front of the crankshaft that is 6 inches in diameter.
I am also wondering if I can remove the impellor from the outdrive and leave the housing, and use the raw water intake through the outdrive to provide water to the inlet of the inboard mounted pump.
Will I need a check valve before the pump to prevent raw water draining back when the engine is stopped, then having the pump start dry ?
My reasoning behind all this is that I was on another boat a couple of weeks ago which was equipped with an inboard mounted water pump, and about 40 miles beyond nowhere, the engine overheated and derated itself. Sure enough, it was a blown impellor, which we were able to change while we bobbed around on the ocean. I was thinking later on, and if you lose an impellor in a lower outdrive, there is no way you will be able to change it on the water, even if you do pack a spare. There are not very many beaches in my part of the world, just rocky flat spots, so beaching with the kicker and waiting for a lower tide would not be a very good option.
Anyway, if anyone has any thoughts on this, they would be appreciated.
Ryan
