Alpha One Gen 2 water pump housing alignment pins

K

KHE

Member
Feb 28, 2012
238
West Michigan
Boat Info
1997 Sea Ray 240 Sundancer
Engines
Mercruiser 5.7L EFI alpha 1 Gen 2 drive
I am going to replace the water pump impeller on my Alpha One gen 2 drive this winter and noticed there are alignment pins that are used to line up the pump housing. I believe they are M6x1.0 thread but does anyone have the length and diameter of the unthreaded portion of the pins?
 
I did mine last year and I'm very meticulous so let me tell you don't bother getting them. The newer gaskets are all in 1 and not the 3 separated ones so they aren't needed. I have twins and both were easy and no issues. Visually make sure it's not touching shaft. Worked for me. Just take your time and don't forget the little oil seal. Took me 4 hours to do 2 and also I sprayed the inner drive under the housing with antifouling paint and cleaned everything and took my time. Easy job.


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Thanks for the info. I was going to make my own pins since $30.00 for esentially a couple of headless bolts is a huge rip off. I did not know the gasket design was changed to a one piece design. Does the kit include instructions since the procedure is different than described in the service manual?

Were the gaskets you used Mercruiser or Sierra parts?

I need to buy some Perfect Seal for the gasket also since the shop manual specifies it for the gasket.
 
+ 1 I have changed my pump a number of times. I made my own alignment pins, but really don't need them. Just make sure the shaft is centered in the housing hole and can't touch the sides. I do mine after every 3rd year, take the drive home over the winter clean it up good, change the pump etc. Also, don't forget to inspect the bellows and gimbal bearing and pressure test the drive while you are at it.
 
I pull my drive every fall so that the bellows are not extended during winter storage since the storage facility moves it in and out and I don't want to have to depend on someone to raise the drive when moving the boat in and out of the facility. That allows me to inspect the gimbal bearing.

As long as there is not any water in the gear oil is there a need to pressure test the drive?
 
If you are not seeing evidence of water in the gear lube and are not using a significant amount of gear lube the pressure testing is probably not necessary, but it is a confirmation that you got everything back together correctly after changing the water pump.

I made my own pressure tester a few years back when I was troubleshooting a gearlube leak, so when I pull the drive and change the gear lube each year it's easy enough to test it.
 
i also pressure test every year, the Alpha Gen II's have lots of places that could wear and leak. This year on our drives that have about 100 hours on them we had both lower shift shaft bushings leak only when pressure was applied to shift them into forward. I wasn't losing any lube this year and there was no water in the drive but now I'm confident for the spring. The other place that notoriously has issues sealing is the quad seal between the two halves, I like knowing it seated properly and went back together before launching the boat.
 
Good points. I'll pressure check the drive before I fill it with gear oil. I added a slight amount of gear oil to the reservoir this year so maybe there is a small leak. Should the "quad seal" be replaced as PM? My boat is a '97 and the seal is likely original.
 
The quad seal goes in the oil passage between the upper and lower haves, it is what seals that passage, it's important because if it fails it allows water into the gearlube. One is included with the waterpump repair kit and should be replaced each time you do a water pump maintenance.

As far as gear lube usage, after every change you are going to have to top off after the lube circulates through the drive and burps out any airbubbles introduced when you filled it. After that initial burp, you really should see no or minimal gear lube usage. I watch mine, but don't worry about actually topping it off until it is at the fill line - I don't stress if it's up or down 1/4". Other than when I actually had a leak, mine never had to be filled in a 50hr season, may down a little, but not below the fill line. If you have a leak it becomes obvious real quick, constantly topping off the gear lube, a sheen in the water etc.
 
I bought he entire mercruiser kit that includes the housing. It has instructions and also had parts you won't use. Has the tool for the shaft seal and I also used the perfect seal on the gasket surface that meets the drive housing like you read. I also use perfect seal on the bolts.


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Be aware that a pressure test doesn't tell the whole store. A seal may work in one direction but fail in the opposite direction. You really need to do a vacuum test as well to get the whole story.
 
I was looking into the SEI kits for next time. Complete kit with hosing is 1/2 the price. Anyone use them?


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Update:

I took the drive apart - the waterpump housing had a groove that was concentric with the driveshaft hole so I needed to purchase the entire kit. Someone has been in there before as I could not see the seal that should be on the driveshaft just above the pump housing. I can see the polished area where a seal was at one time. I thought it might of got lost when I separated the upper and lower housings but I couldn't find it anywhere.

Merc. changed the design again - It was two gaskets with a separate cavitation plate, then they went to a one piece cavitation plate with molded in seals/gaskets. According to my dealer, there were problems with that design so they went back to a different three piece design. The latest is a separate cavitation plate with a upper gasket with a bead of sealer. The third "gasket" is a steel plate. The instructions in the kit are still for the one piece design... My dealer says they install them dry and do not use the alignment pins. After looking at the new parts in the kit, I am glad I didn't buy the pins or make them myself. Merc. changed the design of the housing and the cavitation plate to have a small hole that is just larger than the bolt and the opposite diagonal hole is now a slot whose width is narrow. The remaining to holes are oversized so there is no need for the alignment pins - two of the fasteners act as the alignment pins. The upper gasket is located by the flange in the pump housing and the lower steel gasket's position probably isn't that critical.

Since the kit contained a new carrier seal so I decided to replace that. The gear oil didn't have any water in it so I wasn't going to pressure test the lower unit but since replacing the carier seal, I think I should.

One thing to note for those who are going to do this job is the kit does not contain a seal for the vent plug, only the drain plug so I need to buy one next week.

I'd like to hear from members who have used the latest kit for the Alpha one gen. two drives.
 
I emailed Mercury Marine and they replied back that they are in the process of updating the instruction sheets and that the gaskets are to be installed dry. They were very helpful. It looks like I'll be able to get my drive together this evening.
 
Do you have a photo of the kit? Part number still 817275Q05? I did mine last year and it kit has the 1 gasket and others that I didn't use.


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I didn't take a picture of the components in the kit I bought, but I found this on eBay: http://www.ebay.com/itm/Mercury-Mar...ash=item2ee3100e12:g:ZJYAAOSw2x1XKRtX&vxp=mtr

The latest kit does not include the plate in the lower right - that is the previous generation. The kit I used had a lower steel gasket and an upper paper gasket with a silicone bead like in the photo.

The housing was redesigned so that you do not need the alignment pins - the screws must be inserted in a specific order to keep the pump housing aligned. This is a huge improvement in my opinion.
 
I think I got all those too but also the lower rt in which I used. I liked the 1 price design. I did use the perfect seal on the bottom which might have been the issue as there was a service bulletin. I'm not due his year as I will do them every other.


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Strange that they would include both types of gasket design in one kit. The kit that I bought did not have the one piece design plate or the vent plug seal - I was irritated that after $150.00 for the kit, I still needed to shell out another four bucks for the vent plug seal.
 
4.00. I pay 1.00 each at a dealer and Mercury parts place. I'll look at my kits and see again what parts are left. Pretty sure it had both


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I got it filled with gear lube last night. When I bring the boat home from storage, I'll drain the gear lube reservoir in the engine compartment and pump in more lube from the fill plug.
 
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