1986 Mercruiser Alpha One Lower Unit Removal/Stuck

[raglover]

Hello,<br />I am trying to help a friend change the raw water pump (impeller) in his 1986 Mercruiser Alpha One Stern Drive with a GM 2.5L. I have worked on older outboards for a while but this is my first Stern Drive. I have put the drive in forward gear, removed the front bolt, loosened the two side studs, removed the nuts from the two studs under the ventalation plate, and the hidden screw under the sacraficial Zinc Plate--The lower unit is stuck fast at the rear, near where the hidden screw was. I can get a large gap at the front between the upper and lower halves and the slightest crack all the way to the rear. The large gap at the front tells me there is no binding on the drive shaft or shift linage but did I miss something in the rear? Does anyone have any tips for getting it off? I have tried a thin paint scraper in the gab but I do not like prying to hard on the castings. Also he has a lot of play in the transom when I start rocking on the LU--what if any is normal on a sterndrive? Thanks for any help.

 

[jamesr1]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

There are 2 allen head screws at the back. The one on top holds the small fin on, after you remove the fin there is another one that threads up from the bottom

 

[raglover]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

Thankd for the reply jamesr1. I have already removed the small zinc fin from the top bolt and then I removed the smaller allen screw from the underside and it is still stuck. The top screw (that holds the fin on)is free hanging and loos as it does not appear that it will come out until the lower unit is dropped--is this correct? Might you have any more suggestions? Thanks again

 

[tommays]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

http://www.mercstuff.com/howdoi.htm <br /><br />have a look here<br /><br />tommays

 

[swansont]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

I have a 87 alpha-1, currently sitting in two pieces on my bench. It sounds like your have removed the six nut/bolt connections that I had. Yes the trim tab bolt will just sit there and has to be in before re-assembly (I know, I forgot and had to pull it apart again to insert the bolt, ended up with a seized nylock, ruining a stud). The only thing I can think of, there is an alignment pin, only about a 1/8" diam. X 1/4" long next to the front and rear connections. I doubt that could seize enough to hold the units together though. Have you tried to rock it gently, the lower against the upper? Course you might not want to listen to my advice, I have not had good luck with my I/O.

 

[Haut Medoc]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

Do the rocking thing....It will come apart. You are wise not to pry on them. Try a mallet, if nothing else works. I would be much more concerned with the flex in your transom. There shouldn't be any at all......JK

 

[crazy charlie]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

Get the drive on a table and lay it on the side.Close the gap and start from an even opening.Get 2 flat screwdrivers and Tap 1 screw driver in the front and the other a little in the back.Just a little at a time on each side.You can turn the drive upside down and spray some pb blaster on the drive shaft so it runs down the shaft into the upper.If no grease was applied to the splines when it was last apart ,it could be sticking there.Also take off the grounding washer with a phillips screwdriver at the front of the drive.Go nice and easy a little at a time and it will come apart.Charlie

 

[jamesr1]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

Pull, tug, rock, grunt,,, repeat until the two halves are seperated. Sounds like your just not holding your mouth right.

 

[KRS]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

The entire unit isn't free guys, from the sounds of it he is attempting to pull the bottom from the top while it's on the boat, so he can't lay it down on a workbench and such.

 

[k hupp]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

There are 2 allen head screws at the back. The one on top holds the small fin on, after you remove the fin there is another one that threads up from the bottom

12 years ago I had a 119 merc outboard and removed the lower unit a few times. Now I'm trying to remove the lower unit on1987 alpha 1. The first allen key that holds the fin, the key hole was stripped and key just turned. I automatically began drilling of the bolt head off with a 3/8 bit. I can't remember the size of the bolt. But hope I don't drill too much off the plate teh fin is attached to. I sdhuld have drilled far enough but the unit is still stuck tight. I'm cautious to over drill to big or deep.
Does anyone have any experience like this?

 

[Don S]

Re: 1986 Mercruiser Alpha One Lower Unit Removal/Stuck

You need to start a new thread of your own, not hijack someone elses thread from 2005.
Read the announcement at the top of this forum and the forum rules.