Half moon gear not lining up

Free?Boat

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Oct 26, 2010
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I have a 1972 165hp GM250CI I6. I have been assembling a stash of spare parts and decided to have a spare outdrive for emergencies. I picked it up today and when i tried to install it on the boat tonight the half moon gear for the tilt was out of alignment by a fraction of an inch. Just enough that it won't move the outdrive up and down(the gears slip past each other) but will hold the outdrive in place. Any Thoughts? Is there slight differences in the upper gear cases from different years? All four of the half ion gears I have appear to be identical. Are there any differences in the half moon gears? I am perplexed. Thank you all in advance for your help.
 

southkogs

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Did you get the exact same outdrive (165HP)? The gear ratios are different but, I would think the case dimensions are the same. You have the liners on the trunions, and the ball gear is seated properly, correct?
 

Free?Boat

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Southkogs, I bought a complete outdrive from a 165 and was having it resealed and they found a crack in the upper gearcase housing. I had another upper from a 190HP that had seized so they used that and put the gears from the 165 into that housing. Someone I met once a couple of years ago told a tale of something like this. He shimmed the half moon with two extra washers on the upper bolt, one extra on the middle and none on the third.This tilted the half moon just enough to engage the gears. I am not shure if this will put any undue stresses anywhere else.But I thought I might give it a try. What do you think?
 

southkogs

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The 190 electric shift should have been the same upper as the 165 (I think). I've got a couple of drives (one working and a couple of parts drives) and I can swap quadrant gears with no troubles. Do you have the other quadrant gear? I'm wondering if you've got a warped gear.

I don't know about shimming it - have never seen it done. I don't like the idea (personally), but I don't have enough expertise to tell you it wouldn't work.
 

Free?Boat

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It worked. I took one of the washers out of the top bolt. Tilts up and down smooth as ever!
 

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