92 Mercruiser 3.0 alpha one gen 2 shift shaft oil seal keeps leaking

KKnD

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Jun 15, 2022
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End of last season I noticed gear oil dripping out starboard side weep hole. Since it was end of season I just drained the oil, winterized and will deal with it next spring. Well I'm dealing with it now, I pulled the lower off and pressure tested it (8-10 psi). Found that the shift shaft oil seal was leaking. Replaced the whole unit with a new one (see pic) and pressure tested again, Same result, leaked pressure at 8-10 psi. Returned it got another new one, installed it, made sure all o'rings in place, pressure tested it again and again still leaking at the shift shaft oil seal. This is crazy, I know these are made in China but two new parts that are bad? Or do you think the shift shaft needs to be replaced. Really scratching my head on this one and any advice would be appreciated. Also, I did not pack the oil seal with grease, just lightly greased it with marine grease to help it slide on the shift shaft easy. Is the oil seal supposed to be pack with grease?
 

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KKnD

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Jun 15, 2022
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Time to get a mercury/quicksilver brand assy
Yeah, I'm thinking that too. Reason I bought the Sierra brand is it got pretty good reviews. Just hoping its not another issue I'm missing but no other leaks found in lower unit.
 
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achris

More fish than mountain goat
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May 19, 2004
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27,468
Unfortunately the aftermarket products are genuinely inferior. I've tried to use them but always end up back with OEM. But that didn't always mean Merc. When I'm buying bearings, I buy Timken, base engine parts I go to GM. But for just about anything else I do go to Merc. I hate it, but I do it.

Chris...
 

KKnD

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Joined
Jun 15, 2022
Messages
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Unfortunately the aftermarket products are genuinely inferior. I've tried to use them but always end up back with OEM. But that didn't always mean Merc. When I'm buying bearings, I buy Timken, base engine parts I go to GM. But for just about anything else I do go to Merc. I hate it, but I do it.

Chris...
Was trying to save a couple of bucks but you're right about aftermarket products. I ordered the new Shift Shaft Bushing (OEM) this time. Will post the results once its in.
 
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