splined drive shaft seal

ok, today i dropped the lower unit out of my 1982 merc 50hp to change the impeller due to no tell-tale water. this is my first attempt at doing this. everything came out fine, but when i looked up into the housing where the drive shaft goes in, i noticed 2 splined gaskets/seals 1 large, 1 small, laying there. i guess they got pulled off when i was dropping the LU. the big one looks in good shape, but the smaller of the 2 is kinda chewed up at one end. i figured i would go ahead and replace them while i have it apart, but the exploded parts illustration in my clymer manual, doesnt show the seals listed. however, a couple of pages over when it talks about installing the LU it mentions putting 2 splined seals on the drive shaft. i have searched the parts section of this site, and cant find any splined seals. have they been discontiued and replaced with a different seal? if so what are the names/part number, and can i buy them individually or do i have to order the whole lower unit seal kit? also, does the impeller repair kit, that does not include the top housing, contain the rubber water outlet tube seal? i cant tell from the pic. any other tips in reinstalling the LU, right now the motor is in forward gear. should i leave it in forward, or put in neutral when reinstalling? i know this is a long post with a lot of questions, thanks in advance for any help.

Re: splined drive shaft seal

not sure about yours

but for the older mercs like min, they stopped using a certian seal and switched a fat looking (wide) o-ring.

im not sure what you mean by water outlet tube seal...i didnt have anything of the sort (but i dont know if there should be one)

also, DO NOT move any of the gears while its out. it will be tricky trying to get it back in.

Re: splined drive shaft seal

any others?

Re: splined drive shaft seal

Above your water pump there is a flinger (Item 31), resting on the top of the pump.

On top of your drive shaft there is two seals, as you mentioned (Items 32 and 33)


Merc part numbers:
31 p/n 25-20273 ring, rubber
32 p/n 78654A 1 seat assembly, drive shaft
33 p/n 86304 seal splined, drive shaft

I'll go back and review your other questions...

Re: splined drive shaft seal

Whatever gear it was in when you removed it, leave it there. Doesn't matter which gear it was.

Lower water tube seals (27 and 28) are available, but not included in all kits. Depends on which kit you get. Most times, you just need an impeller, but it depends on the condition of the pump body etc.

Merc part numbers:
27 p/n 26-38452
28 p/n 12-38453

When re-installing the lower unit... be sure to line up the water tube, shift shaft, and drive shaft simultaneously. Don't force it. Wiggle it and it should go in by hand. Turn the flywheel a bit to help line up the drive shaft splines if necessary.

Hope that helps.

Re: splined drive shaft seal

thanks amd, i'm guessing the seals i need are mercury only items, as i could not find them on the iboats website, but found them on another site that sold genuine mercury parts, figures.