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Pre Alpha/Alpha gimbal ring

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larrys toy

New member
I have looked at many discussions regarding gimbal ring wear, but I am not too sure I have an exact answer. What I would like to ask is, what is the acceptable free play? Is it any is too much?
My 888 drive (1976) has 7/16th inch of free play if turning the ring (the drive is out) side to side.
Is this considered too much, or could I safely use it for another season or two. There is no up or down movement.
The last time the boat was out I felt nothing abnormal in the steering.
Thank you.
 
larrys toy said:
I have looked at many discussions regarding gimbal ring wear, but I am not too sure I have an exact answer. What I would like to ask is, what is the acceptable free play? Is it any is too much?
My 888 drive (1976) has 7/16th inch of free play if turning the ring (the drive is out) side to side.
Is this considered too much, or could I safely use it for another season or two. There is no up or down movement.
The last time the boat was out I felt nothing abnormal in the steering.
Thank you.
Click to expand...

Could it possibly just be the splined steering arm splines worn? I understand theat the steerning arms do wear and can be replaced without pulling the motor using a special kit.
 
Never mind my question, I made a decision.
I got my old boat back for free. It runs good and the hull is very nice (the last guy trashed the interior though).
I am going to simply replace it. If I really have to ask, it probably just needs to get done and not worry about it.
 
First you have to understand what all the parts of the gimbal ring do.

you have the ring, the pivots at 3:00 and 9:00 (5/8-18 threaded screw (12 point female) ), a square hole at the top.

The pivots allow the up and down movement of the ring with respect to the drive trimming up and down.


There is a square steering pin that fits into the square hole, the pin has a upper section that is either square(old style) or splined (newer style). The splined upper part of the steering pin has a lever attached to it which the steering cable attaches to the other end at the inboard side behind the motor. (simple explanation)



The upper square opening of the gimbal ring has two stainless steel 3/8-16 SHOULDER BOLTS that go thru it with nuts on the inside of the ring. there are also two slots running down each side of the ring from the square opening. These slots are about 1/8" wide and about 2 inches long.

Now. Over time the aluminum gimbal ring square opening wears and the square to square mating surfaces between the ring and the steering pin gets sloppy. What a properly maintained boat would have had done is the bolts would be tightened to keep the square to square mating parts tight to each other.

The reason for the shoulder bolts (shoulder) is so that when the shoulder has been reached and no more tightening can be done then it is time to replace the gimbal ring and steering pin. If over tightened or the screws are replaced with NON shoulder screws the gimbal ring will break from being over compressed at the slots.

In essence these parts are wear parts and need maintenance or replacement as needed.

There should be NO side to side slop between the gimbal ring and the steering pin. period!

You may want to try to tighten the shoulder screws I refer to. 9/16 socket on the head and a long 9/16 open end on the inside nut.

Tighten it as much as possible and see if this reduces the slop. You may be able to eliminate it completely as sometimes the nuts loosen......
 
Thank you.
Can this be done while still installed on the boat? I have not looked for the 2 bolts you refer too. I would look before asking, but I am at work now. I also have a Mercruiser repair manual at home. This 888 unit has the 2 side mounted trim sensors, so it is a pre alpha unit.

The pivot holes (at 3 and 9) are tight. I am only concered with the small amount of movement in the ring side to side (drive out).

I am new here and these forums are very usefull. I really like this old boat as it behaves great in the waters off the SoCal coast and is a blast to use. The last time I used it, before I gave it away, it ran 44 mph (per GPS) in a stretch from Santa Monica to Malibu. Reading these forums made me aware of the safety concerns of something here being worn and failing, hence, my desire to make it right.
 
here is a pic of the top of the gimbal ring

Yes it can be done while outdrive is attached to the boat.

All alpha I and II MR and R and I drives had the two plastic side mounted trim switch and sender. Many back in pre alpha did not have the sending unit one and had a dummy as most boats back in the days of tri hulls did not have trim guages........
 
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Very nice! Thank you for the pic. I will get into it this weekend. Never really worked on boats, other than basic items.
My unit does have both switches as well as the trim position guage on the dash. The boat is a deep V hull, 18 foot, good amount of freeboard.
 
I just reread your first post....1976..............ummmmmm

I am a r mr and alpha years person...........I was a punk back in '76 and did not care about boats.......only broads......


I was reviewing the manual for that year, I drive.......

The gimbal ring in the pictures shows a splined hole in the gimbal ring. If yours is original it may be that.

If it is that than there is no adjustment as i described before.

If it is a splined hole than the only thing in my opinion that can be done it to but a used cheap alpha 1 gen 1 transom assembly and bring it into the 20th century.....then parts will be available,,,,,,,,,



Take some pics and post when you get the chance.....

It gets tough answering questions for the older stuff as so few still are in operation. I do not see any of that stuff often if ever.......
 
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