Merc 75 hp prop shaft gearcase

[nzahradka]

I'm getting ready to open up the propeller shaft gearcase on my 1986 75 hp Merc (S/N A198913), and I'm doing some homework prior to laying parts on the floor. I'm good with a wrench and have a Clymer manual, but I've never gone past the fuel pump on this hummer. A couple of questions:<br />1)What is "Perfect Seal" and is it necessary? (a fancy Merc name for grease?)<br />2) My bearing carrier has two grease fittings in it (one in front and one in back). Is there an appropriate timing for greasing this?<br />3) When I pull the bearing carrier, does the propeller shaft come out with it? What about the shift clutch? I'm worried I won't get it back in like it came out.<br />By the way, I'm doing this because the manual says you should pull the bearing carrier and clean often if used in salt water + I've got some water getting in the lower unit and I plan to replace seals...<br />I've read other posts on the cover nut, and I'm prepared for that fun.

 

[rodbolt]

Re: Merc 75 hp prop shaft gearcase

hello<br /> if all your doing is for a maint removal its no worries. perfect seal is a liquid non hardening style sealant. works great a tip. make a lower unit stand. I made mine with some angle iron a piece of pipe and an old engine stand. carefuly clean the carrier bore as well as you can with solvent and compressed air. when ready to actually pull the carrier, keep the bore tilted down 10 or 15 degrees. as long as a bunch of debris does not go down the bore during cleaning further removal wont be nessasary. change the carrier oring and the prop shaft seals.the shift cluct,shift pin ,propshaft and all may come out with the carrier. if its corroded badly it may stick in the bore with the reverse gear and back up ring. if it sticks you will have to use the prop shaft threads to make yet another puller.

 

[nzahradka]

Re: Merc 75 hp prop shaft gearcase

Thanks - I will be replacing the water pump as well, and will have to drop the lower unit, but I was wondering if I can do the prop shaft part first before separating the lower unit (in order to eliminate the need to clamp the gear housing).<br /><br />Also - what about the grease fittings?

 

[rodbolt]

Re: Merc 75 hp prop shaft gearcase

hello<br /> its easier to pull the carrier while its on the outboard unless you have a solid stand, I think the greasing intravelis 100 hours or 30 days. its in the manual. not all units had them. they assist in keeping the carrier from corroding. just remember to keep the carrier bore tilted down or all the sand and debris will be in the fwd gear bearings

 

[nzahradka]

Re: Merc 75 hp prop shaft gearcase

Thanks much - I did look back at some old posts and found your same answer on leaving the lu on the motor. I'll let you know how it goes after I get it apart...