need help finding correct water pump / impeller kit for alpha one drive

[tfret]

I have a 1984 5.7L mercruiser, but I know my outdrive is not original. It has a 2:1 gear ratio so I believe it came from a 3.0L boat. My temp runs fine while under way, but gets hot quickly while idleing or motoring at no wake speed. I want to replace the entire water pump / impeller kit but need help getting the right parts. I can't find the serial number on the drive anywhere. Thanks for any help.

 

[ziggy]

Re: need help finding correct water pump / impeller kit for alpha one drive

second item from the bottom in this link.... impeller kit 47-89984T5.. best i know, it fits mc-1 through alpha1...

 

[tfret]

Re: need help finding correct water pump / impeller kit for alpha one drive

Thanks for the link. Does it work regardless of engine size? It doesn't specify. I was thinking the 5.7L impeller pumped more volume than the 3.0L. Maybe the replacement kit covers them all (?) I just want to be sure I get the right thing. Thanks

 

[Eric 3.7LX Alpha 1]

Re: need help finding correct water pump / impeller kit for alpha one drive

You are not sure what year the drive is, the best way to check is to separate the outdrive halves and see if you have a preload pin on the top of the shaft on the lower unit or not. The Complete impeller kits are the same either way except for the lower water pump housing. They are the only difference and it definately matters which one.

Look at these two links. They show pictures of each model and can help you decide which lower half you have.

http://www.mercstuff.com/drive_idprealpha.htm
http://www.mercstuff.com/drive_idalpha.htm

 

[joncrisler]

Re: need help finding correct water pump / impeller kit for alpha one drive

If it is a Alpha 1, all the water pumps are the same regardless of engine size, EXCEPT for the Alpha SS (or Alpha Speedmaster) which is a very rare drive. The only difference on the Alpha SS is the water tube. I believe the Alpha SS was only made on 1985-1987 and discontinued when the Bravo came out in 1988. The gearcase on the Alpha SS is identical to the CLE gearcase on Merc racing outboards.

Just make sure what drive it is- MR-1, Alpha 1 Gen I or Alpha 1 Gen II. Then get the appropriate kit.

 

[tfret]

Re: need help finding correct water pump / impeller kit for alpha one drive

Just ordered Sierra kit # 18-3217 from iboats for $34. I'll have to do this repair by myself. Please advise of any tips or hints. Also, how much does the lower gear case weigh? I just want to plan ahead to avoid any surprises. Thanks for all the help. Simply awesome!

 

[tfret]

Re: need help finding correct water pump / impeller kit for alpha one drive

any idea how much the lower gear case weighs? I just want to know what to expect when I pull it off! Thanks

 

[Fordiesel69]

Re: need help finding correct water pump / impeller kit for alpha one drive

About 30-40 I estimate. I can lift the lower unit be myself with no problem. I would not woory about the lower housing unless you see pieces of rubber missing from the impeller. It is VERY hard to scrape the old gasket material off the lower housing. I did this on my first impeller job and it took about 3 hrs of scraping & spraying gasket remover on it.

Change the upper housing & impeller, seperator plate and gaskets. You should be fine.