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  Topic Review (Newest First)
10-16-2013 12:37 PM
Re: Yanmar 3YM20 New Raw Water Pump Install Questions

RAW water can also be fresh water....
10-16-2013 12:16 PM
Re: Yanmar 3YM20 New Raw Water Pump Install Questions

Its just a bit stiff, I dont want to force it the wrong sure it will turn just fine...Thanks all! Gonna go slap it on!
10-16-2013 11:49 AM
Re: Yanmar 3YM20 New Raw Water Pump Install Questions

With the pulley on the pump, mine turns easy when all is rebuilt. I keep a spare rebuilt pump on board and spare impeller. My number 1 cause for engine issues. My Sherwood pump will work in both rotations, cover is marked so. But as "overboard" mentioned, be careful not to rotate one way then the other. You could damage impeller. I just rebuilt my backup pump after sitting for three years and found the the impeller, although intact, the fins were bent over at the cam spot and do not want to release that shape. I am sure with some use it will straighten out, but I opted to keep that impeller as spare. I rebuilt the pump but did not install the new impeller. I will install the impeller when pump is needed. Easy to do. I might be another few years before I need it.

You say the new pump won't turn? How long has it been sitting since it was manufactured? Are you trying to turn it with the pulley on? I don't think you will be able to turn it with only the shaft.
10-16-2013 11:31 AM
Re: Yanmar 3YM20 New Raw Water Pump Install Questions

the pump will turn by hand. it is designed to rotate in one direction only do not turn it the wrong way you can damage the rubber vanes
10-16-2013 11:06 AM
Re: Yanmar 3YM20 New Raw Water Pump Install Questions

1. Raw water = Sea water
2. Don't tighten the belt too tight like mentioned in manual. A little slack prevents damage to pump shaft.
3. You should be able to turn the pump/pulley without belt, its tight but doable.
4. You could grease the impeller with glycerine or Superlube.
5. Don't throw away your old pump. Recondition it and keep as spare.
10-15-2013 10:46 PM
Yanmar 3YM20 New Raw Water Pump Install Questions

I am going to install a new Raw Water pump (which is it Raw water? Sea Water? Just Water? I've heard them all....)in my Yanmar 3YM20 engine. Is there anything that I should do to make things last longer? I have brand new belts, anything else? Also should I be able to easily turn the pump? Its stiff, and wont turn, I do not want to force things if it will do damage, my thoughts are it needs water to lubricate the impeller. Do I need to spray any lube into it before install? Just checking before I install. Thanks!

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