1991 MerCruiser 3.0 Alpha One

[devon84]

Ok so I'm starting this thread to follow my progress. I bought this boat about 3 weeks ago and had it on the water about an hour and a half when I burnt up the coupler.

Here I am paddling back to the ramp.


I got it home and pulled the outdrive to find this,

The bellows was leaking and completely full of water (but no water getting into the bilge!) I've done tons of research on the boat and drive including about 4 hours on the phone with the MerCruiser guy because nothing on this boat has the SN. Then I called the PO and he explains that he had to have the coupler replaced 10 years ago and that the mechanic didn't put the front motor mount bolts back in! I looked and guess why I burnt up the coupler, lol. So I've got everything but some small odds and ends to get the boat back out on the water, my first question would have to be what grease should I use, AmsOil has a high pressure water resistant grease but I would like to get some advice on this (I use AmsOil on everything I own).

Link to the AmsOil Gease:
AMSOIL Synthetic Water Resistant Grease

Thanks in advance.

 

[Bt Doctur]

Re: 1991 MerCruiser 3.0 Alpha One

regular WP is fine but you need to find out where the water got in from. Unless the 2 housing holes are filled with grease you should have heard/seen water entering. torn bellow?

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

Thanks for the reply Bt Doctur, the bellows is dry rotted I ordered the gimble repair kit that comes with everything. So do you think the AmsOil grease will do the trick.

Thanks

 

[Bt Doctur]

Re: 1991 MerCruiser 3.0 Alpha One

I use the Lubriplate brand waterproof wheel bearing grease, has never let me down.

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

Thanks Bt I called AmsOil and they told me that it would work great I'm going to give it a try as any failure caused by there product will be paid for. I was skeptical at first as many are but after having AmsOil pay for repairs that were caused by there products I'm a believer, they stand by everything they sell.

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

This is going a lot slower than I imagined, I'm an over the road truck driver so I have very little time at home and maximizing my time for my family and getting work done on the boat is difficult. I'm waiting on the coupler to arrive before pulling the motor so I don't have to pay for the hoist twice, even if I have to have it for two days it will be cheaper than renting it to pull the motor and then again to put it back in.

Here's a few pictures I snapped.

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

Can anyone help me out with an easy way to get this cotter pin back in.

 

[Bt Doctur]

Re: 1991 MerCruiser 3.0 Alpha One

Something caused the coupler to go, so you need to inspect the rear motor mounts. There is a fibre type washer the you should be able to rotate.
If there pinched ,then the rear mounts needs to be replaced.

A loose/rotted front mount will do the same thing. Unless you find the actual cause you will be replacing it again.

 

[Bt Doctur]

Re: 1991 MerCruiser 3.0 Alpha One

The manual http://www.boatfix.com/merc/Servmanl/13/13covr2.pdf

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

The engine was definatly out of alignment, I'll take some pictures when I get home to show you what I see. I will also check the rear mounts again but they looked good.

 

[Bt Doctur]

Re: 1991 MerCruiser 3.0 Alpha One

When the rear mounts fail , the engine squats down on the input shaft ,quietly destroying the coupler in as little as 20 hours.
A loose front mount allows the motor to "torque over" and loose rear mounts allow the same thing.
I replace them anytime I remove an engine. I see if I have a housing for pics. There not that expensive, you burn out what left, remove the shell, clean the hole, press new ones in . Can be done with a large "C" clamp.
Friendly with any machinists out there. The top one registers in the top of the cover, self-centering. The lower one is slightly undersized to just fit inside the cover but still support the motor mounts outer shell. Threaded rod pulls both together and drives the bushing in.

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

When the rear mounts fail , the engine squats down on the input shaft ,quietly destroying the coupler in as little as 20 hours.
A loose front mount allows the motor to "torque over" and loose rear mounts allow the same thing.
I replace them anytime I remove an engine. I see if I have a housing for pics. There not that expensive, you burn out what left, remove the shell, clean the hole, press new ones in . Can be done with a large "C" clamp.
Friendly with any machinists out there. The top one registers in the top of the cover, self-centering. The lower one is slightly undersized to just fit inside the cover but still support the motor mounts outer shell. Threaded rod pulls both together and drives the bushing in.

I got the motor out and my rear motor mounts look nothing like those.

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

I've got a lot of work done in the past couple of days and the more work I do the more I find that needs to be done before I can get back on the water. I got my outdrive cart built use a combination of ideas that I found on iBoats. To build it I used a car dolly (FriscoBoater's idea) and some scrap 2x6s and 2x4s I had laying around.






I had to cut notchs for the bullet to fit through bu otherwise I worked perfectly

 

[Bt Doctur]

Re: 1991 MerCruiser 3.0 Alpha One

That tool installs the new rear mounts. Check the height of the inner alum sleeves in relation to the rear housing

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

I also did a full outdrive service.

Greased the u-joints,


Removed the water pump,

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

This is what all the old water pump parts looked like,

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

And finally the new housing, gaskets, and impeller installed!

 

[Bt Doctur]

Re: 1991 MerCruiser 3.0 Alpha One

What about the carrier seal and was the yoke grooved?

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

What about the carrier seal and was the yoke grooved?

I followed achris' video for water pump replacement could you elaborate as to what I should have checked?

 

[devon84]

Re: 1991 MerCruiser 3.0 Alpha One

That tool installs the new rear mounts. Check the height of the inner alum sleeves in relation to the rear housing

They are perfectly level with the top and bottom of the housing and the rubber is in great condition, is this correct?