You should also replace the Alpha Pump Base too, Part 46-44292A3 for $32.00
If you have an older R-Style pre-alpha then you will still use the Alpha One Water Pump Kit
BUT you need a pre-alpha water pump base #46-57234A1 for $35.00.
If you have a newer Alpha Generation II drive (ser number 0D469859 and up or 1991 and newer)
then you need a Alpha One Generation II water pump kit with the stainless housing.
The Kit is 817275Q4 which changes to 817275Q4 for $155.00. No base is required.
It is VERY important to know if you have an Alpha One or a pre-alpha / "R" style drive.
If you screw up and try to install the wrong water pump base you can destroy the outdrive.
Go here to learn more about Alpha Water Pump
replacement procedures.
Some Alpha Ones might not be using the pump in the drive but instead
have elected to use a belt driven sea water pump.
This is usually the case with closed cooling system equipped engines.
Belt Driven Raw Water Pumps are also used on engines with Bravo drives.
The belt driven Mercruiser Raw Water Pump now uses Kit # 46-807151A14 for $105.90.
Inboards
Mercruiser MIE Inboards use a belt driven raw water pump.
The older pumps used to have iron backing plates where the hoses would attach.
For obvious reasons, this caused problems when the hose nipples rusted off.
Mercury then updated the pump design to include a hard plastic rear plate assembly.
The new plastic rear plate helped but the pump was still difficult
to build because it had 3 gaskets, two wear plates, an impeller housing
and the rear plate. Getting all this together without ripping the paper thin
gaskets could be a bit of a trick.
Now if you order a new impeller housing will get an upgrade kit instead.
The old housing is no longer sold but it is for the better!
The Kit consists of the new ONE PIECE water pump housing.
This kit eliminates all the cheesy paper gaskets and multiple pump assembly layers thus reducing the chance of leaks and making it much easier to assemble.
The belt driven Inboard Mercruiser Raw Water Pump now uses update Kit # 46-807151A14 for about $105.90.
The Kit includes a new impeller, the one piece impeller housing, all the bolts and an o-ring.
Water pumps with the Fuel Pump Attached
Click here for more about Mercruiser SeaWater Pumps, SeaWater Pump Kits, Waterpumps and Pump Kits.
Newer Mercruiser Bravo engines and MIE Inboards will have the fuel delivery pump
attached to the raw water pump shaft housing.
Make sure that you turn off any fuel valves before removal.
Use a good line wrench to remove the fuel lines from the pump.
While the pump is off and on the work bench for rebuilding,
you might as well drain out the pump oil and refill it with clean
Mercruiser High Performance Outdrive Oil.
Always grease up the impeller for those first few seconds that the pump is running dry.
Check all the hoses and fuel lines for leaks.
Make SURE you haven't reversed the "in" and "out" water lines.
Don't forget to reopen your fuel valves!
Crank Mounted "Shaker" Pumps
Many non-Mercruiser engines such as Marine Power and Volvo will
use a crankshaft mounted "shaker" pump.
sterndrives.com can supply you with the exact kits but we need
to know exactly which pump you have.
Some of the older Johnson style and early Volvo pumps have become
obsolete and you will have to buy the new style for a replacement.
It is important to try to center the pump during installation or it will wobble and shake really bad.
Circulating Pumps
Block mounted circulating pumps must be of the marine type.
Automotive circulating pumps do not have bronze impellers, stainless backing plates
or stainless steel shafts. They will fail in a few months.
sterndrives.com stocks a very good selection of quality circulation pumps for
GM small block engine and GM big block engines.
The 454 or 7.4L GM Big Block Circulation Pumps are part number 850454--1 for $209.00
(gaskets are included).
The 350 cid, 5.7L, 305 cid, 5.0L GM Small Block Circulation Pumps 850399--1 for $144.45
(gaskets are included).
We also know the scoop for the infamous Mercruiser 470 circulating pump
and what it takes to repair that coolant leaking from the bottom front
of your 470 aluminum block engine.
Click here for more about the 470/3.7L leak issue.
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