Lower Unit Removal!

Paul L

Cadet
Joined
Aug 1, 2001
Messages
23
I'm trying to remove the lower unit on my 1970 50HP Mercury. I've taken the prop off (don't know if that's necessary, and all bolts. I need the impeller replaced (water not cooling engine) So how does this lower unit come off. I read that many people had this same difficulty. I read that the LinkAGES need to come undone!? Where are they!? Can someone help please, thanks! (I'm looking for a manual, so I will get one real soon!)
 

petryshyn

Commander
Joined
Oct 3, 2001
Messages
2,851
Re: Lower Unit Removal!

You're right..get a manual, you'll never regret it!!<br />Did you remove the trim tab bolt? I think its necessary on that one. . .<br />
boat.gif
Happy Boating!
 

Paul L

Cadet
Joined
Aug 1, 2001
Messages
23
Re: Lower Unit Removal!

Trim Tab, yah, the thing (the little fin right)? :) Yup, that's moved, and there was a hidden bolt under there, got that far, but the other end of the bottom part won't budge! So What do I do!? If you think about it, there is some rod that goes down to spin the propeller!? So doesn't something need to be disconnected before the bottom unit comes off!?
 

12Footer

Fleet Admiral
Joined
Mar 25, 2001
Messages
8,217
Re: Lower Unit Removal!

You are obviously missing a bolt.<br />The fact that it is the back, tells me it is probably the bolt under the zinc.
 

tema

Cadet
Joined
Sep 23, 2001
Messages
23
Re: Lower Unit Removal!

No, it's not necessary to remove the prop to replace the impeller. And it's not a missing bolt, and I don't think the driveshaft is stuck. What's stuck is probably the gearshaft, which is located in the front, extending from the engine housing and down into the lower unit. There seems to be a joint just above the l/u that tends to stick. If you use force, you will pull the gearshaft out of the l/u, which is not desirable, so you need to loosen the joint somehow. But in any case, make sure it's in forward gear. Perhaps that's sufficient, I don't know, but that's what the manuals says. Someone else may have more info on how to separate the gearshaft.
 

nickster

Petty Officer 2nd Class
Joined
Jul 11, 2001
Messages
136
Re: Lower Unit Removal!

Paul L There should be 4 nuts to remove on that motor and 2 bolts you must have gotten the 2 boltsif you found the one under the trim tab. There is 2 nuts in front of the trim tab and one on each side. If you have all of them out the unit should drop. It might be a little tight and you might need a rubber mallot but it will come down. the shift rod just slides into a splined area. but if this is a mercury that unit will drop. remember to have the motor in forward when doing this.<br /><br />Thank you and good luck!<br />Nick
 

Paul L

Cadet
Joined
Aug 1, 2001
Messages
23
Re: Lower Unit Removal!

Okay, it's down half way! Doesn't it completely remove!? Let me know please! I got at the rubber impeller, so I should probably just replace that!? It has a nick in it.
 

nickster

Petty Officer 2nd Class
Joined
Jul 11, 2001
Messages
136
Re: Lower Unit Removal!

Paul L if you have that thing down half way it should come all the way down. Deffinately change that impeller if it has a nick out of it, and the impeller should be changed once every 2 years. Be shure to check the water pump housing for wear. If there is any wear change it also.<br /><br />Nick
 
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