Newbie Question(s)....Mercruiser Alpha One Gen I

[MLUY]

Hello all boaters out there, this is my first post...but, just to let you know I am a complete novice on this subject.
A couple of years ago I bought an boat on E-bay (by accident, never expected I would win it)
Luckily I used to have a friend living closeby knowing about stern drives, and he always used to help me out.
Since he moved, my boat has been idle with a impeller change job half finished....so I am a bit stuck.

Anyway...with Summer on the way I decided to do it myself and learn the job as I go, hope you guys (any ladies?) can help me out a bit.
I also would like to do maintenance to vital parts (once I found out what they are and how to do it)
The boat is pretty old and driven by a Mercruiser Alpha one stern drive gen I , driven by a 3.0 lit MCM engine.

The lower leg is off and the upper section still connected to the boat.
Impeller, and gaskets are bought and ready to install but first I would like to understand the mechanics of the drive a bit.

My first question (probably of many more to come) is this:

The propeller is completely locked, it does not go forward or backward.
What exactly is going on? (I noticed the lower leg was taken off whilst throttle was in neutral)
The main shaft can be turned freely in both directions by hand easily, but propeller does not respond.
I tried turning the shift shaft into forward or backward but even with a plier I cant get it into gear.
I am afraid I might damage the teeth or worse inside, so question is is this normal and could somebody explain?

 

[alldodge]

Howdy

The drive should be taken off and on with the throttle lever in full forward position.

The drive shaft moves but the prop does not, that's a problem. I would start by taking the prop off and see if you can find out why.

 

[thumpar]

Since only the lower unit was removed it should not have damaged anything since the shift shoe is in the upper unit. You should easily be able to shift it by hand. When you turn the shaft does the prop lock at all?

 

[MLUY]

Thanks for your help, I just took off the propeller and it was completely ceased up, the grease was crumbling, complete lack of maintenance I guess. Now everything works, when I turn the shiftshaft the propeller shaft goes in forward, neutral and back.

 

[alldodge]

Lack of maintenance gets them every time. You could look at a rebuild or get a ne SEI lower

 

[Rick Stephens]

Since the gears are working, time to assemble the water pump.

After the water pump, it is probably best to pull the upper and marry the two off the boat. The lower shift shaft should be turned fully clockwise, looking down at it. That is in forward gear. The propeller shaft should then be in gear when turned counter clockwise. With it in that position you will be able to turn the shift shoe on the upper until it faces directly fore and aft - with the shoe pointing forward. You will then be able to properly marry the halves.

 

[thumpar]

I would also check alignment, gimbal bearing and ujoints when you have the upper unit off the boat. You can also inspect the bellows. The only way to properly check all those is with the upper off the boat.

 

[MLUY]

Ok thanks for the advise guys!, I will try and do what you all mentioned,
I have now ordered my service manual ....but if I get stuck (probably will somewhere) I will be back here.

One question I have with regards to the waterpump, on all the videos I have seen I have not seen a nut sitting on the main shaft holding down the gaskets of the water-pump. I thought I have a Alpha One Gen I, but looks like they are not all the same.......Am I supposed to hold the shaft (hope I don't damage it then) and then bolt this nut off or am I missing something? I don't think the gaskets can not come off without the nut being removed.

 

[thumpar]

Something is not right. That shouldn't be there.

 

[Rick Stephens]

That doesn't even look like the core of the impeller. Wonder where that came from? Did you try and pry it up and off the shaft? Don't turn it! Just straight up.

 

[MLUY]

That doesn't even look like the core of the impeller. Wonder where that came from? Did you try and pry it up and off the shaft? Don't turn it! Just straight up.

Thanks Rick / Thumpar... you are completely right...
When I see a Nut (or looks like one) my first reaction is to screw it off.....
But its so logical (in hindsight)..I pryed it off and its become clear to me now its the inner part of the old impeller!
The old impeller is completely gone but the steel nut/tube remained on the shaft

 

[Rick Stephens]

Some off brand piece of junk impeller. Your new one looks right. I've never seen an impeller core that was just zinc coated steel. Bet it runs cooler

 

[MLUY]

I have some questions on the shift shaft, hope somebody can help me with this...
There is alot of play in the shift shaft connector (upper leg), is this normal?

I used to have a lot of problems to shift from forward to backward gear.

This is the way the shift shaft looks now from close-up sitting in the lower gear case.




From the mercruiser parts website (my manual has not yet arrived) below I think I can see up to rubber washer no 51
So I think I only need part 52, Washer (.390 x 1.00 x .06) not sure what these numbers mean inches? outer/inner diam + wall thickness?

After taking off the lower leg, my friend left me with a glass jar with these items below. (except water-pump housing/impeller)







The washer on top right is about 2mm thick, is this where it supposed to be?
Forgive my ignorance but it looks a bit strange place for a washer, just lying loose?

 

[Rick Stephens]

Yes, the intermediate shift shaft is loose goosey and sits on the lower splined shaft fairly secure. Yours looks correct.

The splined shaft must have the stainless washer on the rubber washer.

 

[MLUY]

Yes, the intermediate shift shaft is loose goosey and sits on the lower splined shaft fairly secure. Yours looks correct.

The splined shaft must have the stainless washer on the rubber washer.

Thanks ,
When you look at my first pic I can see a rubber ring against the splined shaft
Is that part of the seal (no 50) or the rubber washer (no 51)?

Is the am not sure if the washer is that I have is no 50 and is installed correctly as per last pic.

Or does the steel washer maybe sit inside the split-ring directly against the rubber? , seems more logical...

 

[Rick Stephens]

The rubber washer (#51) sits on the splined shaft and is pretty secure. The stainless washer just drop on over the top. It gets lost a lot....