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looking for help / advice omc outdrive

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louies87grady

New member
I had to replace the gimbal unit on my 87 4.3 grady the original one was corroded terribly, had to have the transom rebuilt a well. I purchased a gimbal unit off of ebay and by the looks it was the correct one barely any use. However last nigh after a few hours while attempting to put the lower unit back together it simply would not slide in and seat. the original outdrive number is 984757. the new to me is 985288. the new one is already mounted . What is the problem or solution.
 
My question remains, did you set alignment?? You had the transom rebuilt. That involves cutting a new hole. Even using a transom drill fixture there are variables. If the forward mounts were tampered with at all, you have further disturbed the alignment.

So how far from seating? 1/4", 1/2", more?
If out of alignment he shaft may/will begin to slide into the coupler & slowly bind most as you push more.
 
when the transom was re built it was done from the inside of the boat leave the exterior wall intact with the mount holes and hole for gimbal mount. i dont know how to check alignment after that. we had no issues with the bell house brackets bolting on to the transom mounts.
 
1777918255739.jpeg
 
The drilling fixture tool looks like this. Even then alignment needs to be set using an alignment tool similar to this.

1777919028433.jpeg
 
so thats interesting , never seen that bracket before but the wholes for the gimbal were still there i had the fiberglass guy purposefully leave them for alignment. im really concerned about the gimbals to be honest and what are the differences
 
Alignment should be checked yearly whenever you have the drive off. The 2 best tools to have when you service your own I/O is an alignment tool and an outdrive jack. Front and rear engine mounts can settle over time and that changes alignment. If not done the coupler may fail
prematurely. The pattern that the splines in the coupler makes on the alignment tool should be even all the way around.
checking alignment.jpg
 
That "bracket" as you call it the transom drilling fixture. You will most likely never see one because it is used at the boat manufacturer level to cut & drill the holes.
You however just simply backdrilled the holes using a maybe 3/16" thick fiberglass template. Presumably, just the depth of the center tip of your drill bit was enough to cause your 1/2" diameter holes to not be perfectly centered where they should be. And without the guides, you most likely did not drill perfectly square (as in 90 degrees) to the transom. So now your holes have come thru to the inside a bit off.

Did the transom plate with studs simply slip in with little effort or did the studs tear their way thru the plywood as they were forced in?

Did you need to ream the holes larger to install it?

Any reaming to fit, any amount of crookedness will cause the inner plate to be slightly out of its original position with regards to the forward mounts. Now engine alignment is out of adjustment not to mention sloppy workmanship.

You'll need an alignment tool to get things happy.
 
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