Good news about crank driven sea water pumps
#21
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There must be a lot more restriction internally in the cooling passages of an Alpha vs a Bravo.
#23
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I'm not sure but I need to know...I am planing on pulling suction through my Bravos in my 255.
#24
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Has nothing to do with restriction. Both the alpha and bravo units are close in the size of water passages / hoses. The alpha pushes water into the boat. THe bravo sucks it in. Suction requires reinforced hose, or it will collapse. Suction hose on a car is the same - reinforced.
#25
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This pump set up works great on both alpha and bravo.Big and small blocks.You must use a wire reinforced suction line.I use blue stripe shields exhaust hose 1 1/4"ID.Cools fine even big cube motors.Advantage is when you are out running hard you don't have to worry about blowing a belt off and cooking a motor.Johnson pumps makes these and they can be bought for about 170.00 bucks make for a neater installation with less belts.I have cam drive pumps that also work well. Just my 2 cents JOHN SR
#26
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Older thread, new question. I'm a cruiser, not a go faster but you guys seem to be on the cutting edge. I have a 1999 330 SR Sundancer. The engines are 2007 Mercruiser 6.2L Horizons with the single point air pump drain system and the dreaded Merc RWC pump.
My raw water intakes are thru hull. I have V-Drives so plenty of room between the transom and the flywheel.
Would it be possible to convert these engines to a Johnson F6B-9 raw water pump and maintain the single point system?
If not, aside from the obvious ups to the crank mounted pumps, what are the downsides to doing the conversion (if possible) to my boat.
At 60 years old and 6'4", my ER crawling days are coming to a close but I'm tired of paying several hundred to a Mech to do a job that I could do given the proper setup.
TIA.
David
My raw water intakes are thru hull. I have V-Drives so plenty of room between the transom and the flywheel.
Would it be possible to convert these engines to a Johnson F6B-9 raw water pump and maintain the single point system?
If not, aside from the obvious ups to the crank mounted pumps, what are the downsides to doing the conversion (if possible) to my boat.
At 60 years old and 6'4", my ER crawling days are coming to a close but I'm tired of paying several hundred to a Mech to do a job that I could do given the proper setup.
TIA.
David
#27
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If someone can post pics from me I will show that crank mounted pumps do have a flaw upon engine shut down as to the shape it can put the impeller into especially during winterization..