Need parts help for Alpha 1 Gen 1 outdrive

[jimmyc607]

I started to do my yearly service on my Alpha 1 Gen 1 outdrive and upon draining the gear lube I found quite a bit of water in it. I then pulled the drive off and found that my water pump tube was very melted, the housing itself looks like it got pretty hot with some bubbling on it as well. The impeller also looks to be in rough shape so I know I need a full water pump kit.

My question is which water pump would I need for a 1990 Alpha 1 Gen 1 with a 4.3? The serial number on my outdrive isn't readable unfortunately

Also since it appears there was some pretty significant overheating going on at some point at the end of last season what else should I look to replace?

Thanks ahead!

 

[ktbarrentine]

Re: Need parts help for Alpha 1 Gen 1 outdrive

I'm answering based on the similarity of our drives, so I will give you what I know....without the benefit of having your dive serial number (but I bet it is not far off from mine).


Try looking at these for starters:
46-44292A3 : BASE ASSY-W/P
47-89984T5 : REPAIR KIT-W/P
Teleflex Marine 18-3217 Impeller Kit
I got mine at (at an undisclosed online source) but you can get them here, there, everywhere, even ebay and amazon.
You had what looks to be a serious overheat at one point or another. On your watch? did you see temps go up? So here is what you are looking at:

Look closely at your water pocket cover (where the water pump tube enters the upper half of the drive). It is plastic and it does melt and if it does not seal, you will not cure your overheat problem. And it is a PITA to replace, because the bolts can and do break, and sometimes render the upper unuseable after that, so be very carefull and only look to replace that if you really think you need to.
Next...you need to inspect your exhaust shutters in your Y pipes. On a serious overheat, these melt, too, and sometimes you find pieces in your bell housing when you pull the drive (sometimes even in the drive exhaust area, too, found when you split the drive).
Next, since you say you had water in your oil.....how does your drive bellows look? Anything suspicious in there? (water/oil)...if so, how do your U-joints look and feel? rusty at all? And how about your gimbal bearing? smooth as silk?
Next....youve got at least one seal leaking that let water into your drive... If you had water in your bellows, then most likely your yoke shaft seal. You need to do pressure tests to confirm what you have. I pressure test each half of the drive when I first pull them apart so get an "as found" condition check. Fix any leaking seals and such (some way more involved that others, and take special tools), then after impeller replacement, I recheck both halves independently, then a final pressure test when all put back together.
Thats the "bulk" of your excitement.... more to follow as others add on. Good luck! You've got work ahead of you!

And visit the two stickies at the top of this forum for extremely necessary information and links you will need (tools, tips, testers, manuals, guides, etc)

 

[jimmyc607]

Re: Need parts help for Alpha 1 Gen 1 outdrive

Thank you very much for all the great info. To answer some of your questions the boat did start to get hot towards the end of last summer when it sat at idle. The temp would climb up but if the boat was in gear or moving at all it would settle back down to the normal 150ish.

My water pocket cover is the one with a brass tube coming from it correct? If so mine appears to be rubber and it doesn't seem to be too bad but I will look it over more closely.

How can I inspect the exhaust shutters? I did not find any pieces anywhere in the drive or bellhousing. My bellows and gimbal were replaced the beginning of last season and they all look to be in good shape still but I do have gear oil in the driveshaft bellow. The U-joints are not rusty and look good as well.

I looked over the "adults only" and DIY sections here and will build a pressure tester and test both my upper and lower units seperately over the weekend. I would prefer to replace pretty much all the seals and gaskets I can myself and as many as I can so I do not have to deal with this issue again (hopefully).

 

[ktbarrentine]

Re: Need parts help for Alpha 1 Gen 1 outdrive

You pull your elbows off (inside the engine compartment) to look down into the "Y" pipe to inspect/replace shutters. Your overheat condition doesn't sound like it was bad enough after all to have done anything to the shutters, and not finding any pieces when you pulled the drive is a good sign, so you "may" have lucked out. I inspected my shutters after a similar overheat scenario a couple years ago and they were fine. It is a bit of a chore to get to the shutters, but if you are up for it....go for it! You'll learn more as you go. (getting the rubber boots off a boat that vintage is a challenge sometimes....they get stuck).

If you have gear oil in your driveshaft bellows (was that the reflection I saw in your photo?) then you have a yoke seal leak.... That is another challenging but DIY-able job.... lots of threads in this forum to help you, plus lots of good mechanics on here to chime in when you need tech assist. (By the way...its called a bellows, even if it is just one. "Bellow" is the sound you make when you have to replace one!:facepalm.

 

[Watermann]

Re: Need parts help for Alpha 1 Gen 1 outdrive

Jimmy, I'm not a Mercruiser expert by any means but be sure of what outdrive you have before ordering the parts. You said you have a 1990 A1G1. The Mercruiser Alpha One Generation I outdrive dating from 1972 through 1983 has a square upper gearcase cap with an eye attached to the 4 1/2-by-4 1/2-inch cap.

The Alpha One Generation II upper gear case has a rectangular top cap that's 4 1/2 by 6 1/2 inches, 2 inches larger than the Generation I outdrive. The "Gen II" Alpha One also does not offer a lifting ring on top of the drive cap.

I think a 1990 would be a A1G2?

 

[mercs4mark]

Re: Need parts help for Alpha 1 Gen 1 outdrive

The water in your drive may have come from the overheat also if the water pump base was damaged. I would replace the whole water pump and do a pressure test of both halves.

 

[ktbarrentine]

Re: Need parts help for Alpha 1 Gen 1 outdrive

I think a 1990 would be a A1G2?

1990 was the last year of the Alpha-1 NON Gen II. Would have really like to have his ser number but he cant provide it. He indicated the water pocket cover looked ok on his upper. Gen II does not have a water pocket cover.

 

[jimmyc607]

Re: Need parts help for Alpha 1 Gen 1 outdrive

I've had some time to be able to look into the drive further this weekend and found that the top water pocket cover does not seem to be leaking from what I can tell but there is some bubbling on the rubber from the previous overheat.

I also began pressure testing the drives but what do you guys use to plus the oil galley to keep it air tight? I was able to test the lower and just held my finger over the hole for a few minutes and the psi did not seem to drop at all. The upper however does seem to leak pretty steadily using this technique.

I know the yoke seal must be leaking since I have gear oil in my bellows, how difficult of a job is this? I am very mechanically inclined when it comes to cars and in general but do not have a ton of experience with boats.

Thanks for the help this far it's much appreciated!

 

[Watermann]

Re: Need parts help for Alpha 1 Gen 1 outdrive

Jimmy it the same as how you learned to work on cars, dive right in but with one exception, get a manual and follow it.

 

[jimmyc607]

Re: Need parts help for Alpha 1 Gen 1 outdrive

I dove into this head first yesterday and managed to make a tool to get the yoke nut off pretty easily. Once I did that I pulled out the yoke assembly and put the yoke into a vise to remove the driveshaft nut, this nut should have been super tight right?

I put my socket on it and it literally spun right off, what ft lb should this nut be torqued too? After looking at the yoke seal it looks to be fairly new and in perfect condition so I am kinda thinking the issue might have been an improperly torqued nut or maybe it backed itself off somehow?

 

[jimmyc607]

Re: Need parts help for Alpha 1 Gen 1 outdrive

I managed to get the upper and lower drives rebuilt with new seals, new water pump, and o-rings gaskets everywhere I could. Got the boat out yesterday and everything worked flawlessly! Put in a solid couple hours of testing and came home and checked everything back over, drained the gear lube to check for water and had none! Thanks for all the advice and help guys!

My only issue now is i'm getting some water from somewhere in my bilge. I had this problem last season as well and could not figure it out. The bellows are all new and not leaking. Is there anywhere else I should look for? I can't visually see anyplace water is coming in while on the lake but it's definitely seeping in from somewhere. If I leave the boat in the water overnight by morning I have a few inches of water in the bilge.

 

[Bondo]

Re: Need parts help for Alpha 1 Gen 1 outdrive

I managed to get the upper and lower drives rebuilt with new seals, new water pump, and o-rings gaskets everywhere I could. Got the boat out yesterday and everything worked flawlessly! Put in a solid couple hours of testing and came home and checked everything back over, drained the gear lube to check for water and had none! Thanks for all the advice and help guys!

My only issue now is i'm getting some water from somewhere in my bilge. I had this problem last season as well and could not figure it out. The bellows are all new and not leaking. Is there anywhere else I should look for? I can't visually see anyplace water is coming in while on the lake but it's definitely seeping in from somewhere. If I leave the boat in the water overnight by morning I have a few inches of water in the bilge.

Ayuh,... Bein' a '90, I'd guess the transom is gettin' rotten,...

A digital camera helps in findin' leaks, as it'll fit anywhere yer hand will, 'n head won't,...

 

[jimmyc607]

Re: Need parts help for Alpha 1 Gen 1 outdrive

Definitely not the transom, the boat has always been stored inside and under a cover and everything is solid there. The digi camera is a good idea, the only problem is I have to have the boat in the water to be able to look for the leaks so that makes it that much more of a pain.

 

[Watermann]

Re: Need parts help for Alpha 1 Gen 1 outdrive

Get a float switch for your bilge pump or... When on the trailer, add some water to the inside and get underneath to see where it drips out.

 

[jimmyc607]

Re: Need parts help for Alpha 1 Gen 1 outdrive

I thought about the float switch for my bilge since the boat is never really left in the water but I would rather fix the problem if possible and not too overly difficult.

Great suggestion on adding water to the bilge though and seeing if I can see it coming out from anywhere, I will definitely give that a try