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Lower unit separation

jknoah

Member
"Hi,someone can help me? I nee

"Hi,someone can help me? I need to change a water pump blade but I couldn't disassemble the lower unit. I think I remove all bolts(two on side and one under the fin of the lower unit)but it doesn't move at all.Do I miss any bolt? I carefully checked around lower unit... couldn't find any more bolt.I know there is a bolt inside trim tap sit place for some other model however, my motor seems like doesn't have one because I can't remove trim tap either. My old merc is 50HP 4 cyl 78 year product serial# 5109827 please help!"
 
"I think there's four bolt

"I think there's four bolts holding that one on. Keep looking. If not, the driveshaft could be stuck in the powerhead.

Jeff"
 
"Fastjeff is correct, 2 5/8 nu

"Fastjeff is correct, 2 5/8 nuts up front, 1 9/16 nut in back, remove trim tab to find 1 additional 9/16 nut tucked up in the whole. The trim tab I think is a 1/2, 12 point socket."
 
"Ok, the 4th nut is holding th

"Ok, the 4th nut is holding the unit but how can I remove the trim tap? The trim tap's nut is deep inside mid section body and the hole is too small to use socket.Can I just force to turn the trim tap to loosen it? or should I use special tool to loosen it?"
 
"1/4 inch drive socket, as sta

"1/4 inch drive socket, as stated above I believe its a 1/2 socket with 12 points (very common socket). Do not force it, you were joking right"
 
Also I found that the trim tap

Also I found that the trim tap nut is not the same as regular hex nut . It looks like female tread in the mid section body itself.And the trim tap's bolt size is looks smaller than 1/2 inch.
 
"Then try a 7/16 socket, 12 po

"Then try a 7/16 socket, 12 point. Don't make me come over there and do it myself
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"No , Mr JB I can't app

"No , Mr JB I can't apply the socket as I said the hole is too small. The socket wouldn't go inside the hole"
 
"Yes ,You are Right It 's

"Yes ,You are Right It 's 7/16 socket. It's a pretty simple job. Sorry to bother you guys . Thanks Mr JB and fastJeff GOD BLESS YOU!"
 
"-----------------------------

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You're welcome, but now you gottqa get that sucker back on!

Jeff
That's a new post for sure, why do I only have rev and nuetral?????"
 
"The shifter rod is out of pos

"The shifter rod is out of position. Drop it down again and put both the LU and shifter in neutral, then carefully bolt it back up. I've been having good luck doing it that way (vs. forward).

Jeff"
 
"I come back ,jeff because I

"I come back ,jeff because I found the other problem . I have a another similar 50 HP 4-cyl MERC 500 blue band motor. Now this one need to replace oil seal of the bottom part of water pump. The Problem is there is no serial# on this motor so don't know year product of this one. But I can guess that it's year 73 product because I'v seen exactly same motor in Ebay. how can I get the replacement part? The only information I got is the part #. 46-65496 is molded on bottom part of plastic water pump body. any luck with this?"
 
"What you'll have to do it

"What you'll have to do it carefully remove the seal, then take it and the housing to a good bearing store and have them match it up. Take the shaft along too.

Jeff"
 
I am sorry if this has been as

I am sorry if this has been asked somewhere else...I can't find it anywhere.

I have a 1986 Mercury Classic 50 and I am trying to remove the lower unit to change the impeller. I loosened the two bolts (left and right sides) in the front. I removed four near the propellor. It only goes down about 3/4 inch and stops.

I have read that I need to put the gear in forward all the way. I also read that it is different for most motors. Can anyone help me with this one?

Thanks!!
 
"Carefully try separating it w

"Carefully try separating it with some wooden wedges. If it drops 3/4 inch, then only stubbornness is holding it.

Jeff"
 
"..."Where does the gear n

"..."Where does the gear need to be? "

If you mean, in what gear should it be, I've had good luck using neutral.

Jeff"
 
"Thanks Jeff,

We ended up p


"Thanks Jeff,

We ended up putting it in Forward, putting a ratchet strap around the lower unit and the other end of the strap to a tree. Then we tugged and hit the bottom of the unit with a rubber mallet until it dropped. Even then it was a pain! The local marina told us we were ok to pound with the rubber mallet but not on the fins above the lower unit because they would break.

Impeller changed and ready to go!

Thanks for your help."
 
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