Dolphin Marine Service
Old World Craftsmanship with New Technology
205 Pennsylvania Ave. Fortescue, NJ 08321
856-447-3067
REPAIR / REPLACEMENT OF THE RAW WATER PUMP ON MERCRUISER OUTDRIVES SERIES #1 AND ALPHA GEN I
Below you will find information on repair / replacement of the raw water pump on Mercruiser outdrives, series # 1 and Alpha Gen I's. We do not claim to be experts in all fields. Nor can we promise to be correct on all issues. Nor can we address the content of these pages. (Please read our legal disclaimer page)
But, I hope you will find this page useful. We want to thank Aftermarket Marine for their technical assistance with this page. Aftermarket Marine is a supplier of high quality aftermarket parts for outboards, inboards, and inboard / outboards to Dolphin Marine Service.
REPAIR / REPLACEMENT OF THE RAW WATER PUMP ON MERCRUISER OUTDRIVES, SERIES #1 AND ALPHA GEN I
1)
Drain the lower unit oil from the outdrive.
2)Adjust the outdrive so it is half tilted up, and shift in forward gear.
3)Remove the anode with an allen wrench, (size 5/16 or 3/8).
4)Remove 5/16 socket head bolt, below the anode.
5)Remove the two 5/8 locknuts countersunk in cavition plate above the prop.
6)Remove the 5/8 nut on leading edge of drive, (facing up).
7)Remove the two 5/8 nuts visible from either side in middle of drive. As you remove these the drive may want to come off freely. It is recommended that you have two people available to assist in lowering the lower drive section.
8)There is a small "O" ring like piece on the mating surface of the lower unit. It is on the port side, near the front. Remove this and save it for now.
9)Look to see that the copper water tube stayed in upper drive, if it did not, (and it pulled out with the lower unit), put it back in the upper section.
10)Look to see if the plastic tube stayed in water pump, if not check copper tube. If it stayed attached to the copper tube, be careful removing it as not to damage either the plastic or copper tube.
11)Look to see if the "O" ring for shaft stayed in its groove, if missing check above the seal to locate.
12)Remove the nuts and bolt that retain the water pump upper housing.
13)Carefully pry the upper housing up and off drive shaft, you will have to remove the "O" ring and seal ring.
14)Lift impeller up and off of the shaft. Watch for the key that turns impeller.
15)Remove the wear plate and gaskets below the impeller.
16)If the pump was run without water, or the housing (upper or lower) appears to be deformed or distorted in any way, the housing must be replaced.
17)To change the lower housing, pry it up with two screwdrivers.
17a)Replace the base gasket, base, and "O" ring and check seals in base.
17b)Slide the base, with gasket in place, down the shaft and seat it.
18)Place the new wear plate with gaskets over the base, large gasket hole towards the top.
19)Slide the lubricated impeller, (a light oil coating) down the shaft and over the woodruff key replaced in the slot. (Be careful the woodruff key does not slide out of the slot when placing the impeller in position)
20)Slide the upper housing down the shaft, turn the shaft clockwise while pressing the upper housing down on the impeller.
21)Reinstall the bolt and nuts, (do not overtighten), replace "O" ring, seal ring, and the plastic tube.
22)Check that rubber seal, which accepts the copper tube, is in place in upper housing under plastic tube.
23)At this point, replace the small "O" ring like piece mentioned previously in step 8.
24)Turn shift shaft, in front of drive, clockwise, while appling pressure to the prop counter clockwise. The shift shaft should lock facing forward. Check for the "O" ring like piece (from step 8 and 23) on the oil passage between parts has not moved.
25)Using two people, carefully the lift drive back up, line up copper tube into plastic tube.
26)Line up the studs and lift gently, this is where the shifting shaft must be aligned.
27)As soon as the brass connector for the shift shaft reaches the splined shaft in the lower unit, use it as a tool.
28)Turn the shift shaft with brass piece clockwise and continue to apply pressure to the prop counter clockwise, when it stops it must be facing forward (towards the bow).
29)If the point of brass shift arm is not pointing forward, (when it turned), lift it and change its position on the splines. Repeat step #28.
30)At this point apply a greater force to the prop counter clockwise to turn drive shaft, as you lift the drive. Continue this until splines on drive line up and the lower unit seats into the upper drive unit.
31)Be sure the socket head bolt for the anode trim tab is in place.
32)Start the two 5/8 nuts (from step 7) on the sides and snug the unit upward.
33)Rotate the prop back and forth while shifting, to check for proper Forward - Neutral - Reverse shifting.
34)If shifting is wrong go back to step #27.
35)Replace the rest of the 5/8 nuts and tighten.
36)Replace the 5/16 socket head bolt and replace trim tab anode facing to slightly left.
37)Refill the outdrive gear oil from the bottom, and make sure it comes out of top hole.
38)Check for oil leaks.
39)Wait 24 hours and check oil level and for leaks.
40)Check oil level a few times over the next few trips.
Remember if you have a problem, help is only an e-mail away.
