What water pump kit do I need?

Thagan

Cadet
Joined
May 27, 2017
Messages
24
Time to replace the water pump/impeller in the outdrive. I've looked for the last couple hours and I still can't figure out what kit I need to buy. I have an '84 Blue Water with a 120 Mercruiser and an Aplha 1 (Gen 1) outdrive. I have entered the serial number 6806933 into a parts lookup and it gives me a whole bunch of options and I'm confused. Any idea what I need?

Thanks!
 

Fun Times

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May 16, 2009
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8,805
It's the lower base you need to be careful on buying as there is a difference... But for the impellers, there are mostly two choices to choose from. One is a impeller kit which would mostly be the rubber impeller and a few mounting gaskets + a small tube while the water pump kit would have more gaskets, a upper water pump housing plus the impeller.

While there might be some places that add/offer a lower base in a kit, you have to know for sure what model the base will fit in....Other than that it's best to order the lower base (kit = more gaskets) separately should you find you need it. Which just depends on the situation such as if it's been a while of not being changed out or you know the impeller pump area really became overheated causing damage in the area... This info is outside of not knowing if you need a new lower base or not to where your wanting to have a new impeller kit already ordered/ready to go before you open up the lower unit drive for pre inspection....< Hoping for a one day work day vs waiting a few days to order parts after teardown...Just depends on "your" situation.

The Alpha and "R" water pump bases are DIFFERENT!
They have different part numbers and will not interchange!
They LOOK almost identical but they are not.
If you have a pre-load pin at the top of the driveshaft, you have an "R" drive.
If you have NO pre-load pin, then you have an Alpha drive.
If you have NO pre-load pin and a stainless housing, then you have an Alpha Gen 2.
Water Pump Kits!
Kits include Impeller, Wear Plate,
Gaskets, O-rings, Upper Housing,
and small parts kit.
Part Number 46-96148A8 For MC-I, R, MR & Alpha One.
Part Number 46-44292A3 Alpha One Water Pump Base (Fits Alpha One ONLY)
Part Number 46-57234A1 PreAlpha One Water Pump Base (Fits R style with the pre-load pin)
Mercury-Mercruiser 47-89984T5 is just an IMPELLER KIT 'Water Pump...http://www.mercruiserparts.com/89984t5-repair-kit-w-p

Also if you are having overheating issues with this designed stern drive then there is also an Water Pocket Cover Kit that fits in the upper unit driveshaft housing that if became damaged due to heat, etc., then you could continue to have heating issues until repaired. http://www.iboats.com/Boat-Parts-Acc...6649&q=42724A3

http://www.iboats.com/R-MR-ALPHA-ONE...iew_id.1704120

Hope this helps some, good luck.
 
Last edited:

Thagan

Cadet
Joined
May 27, 2017
Messages
24
Found my thread! Thank you so much! It's much appreciated and I ordered the kit I need.

Thanks!
 
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