74' 50hp water pump

Jerseymk2

Cadet
Joined
Sep 23, 2009
Messages
15
ok so my buddy asked me to do the water pump in his 50hp he says its a 74 but he just bought it lol it looks like early to mid 70's it has the 3 piece motor cover and its a thuinderbolt ign. so heres my problem once i had had all the bolts out even the one hiding under the zinc the drive will only seperate a half inch or so i thought the shift rod would just drop like on many others that i have done so then i looked under the carb thinking i had to disconnect there like many of the johnsons but all i see is the shift arm and the linkage but there held together with a roll pin? any ideas im not often defeated by inanimate object lol thank you ahead of time
 

ram50

Cadet
Joined
May 5, 2010
Messages
20
Re: 74' 50hp water pump

Ive got a 1975 merc. and Just replaced my water pump. I had to do a little teasing to get it to drop all the way. it had all kind of crud in it. I used a rubber mallet. do not pry. Make sure your in neutral.
 

Jerseymk2

Cadet
Joined
Sep 23, 2009
Messages
15
Re: 74' 50hp water pump

usually the just drop im well aware im a mercruiser tech for a living but very very rarely deal with mercury OB's problem is its for a friend and u can see where he has pryed at it lol but i dont see an easy way to disconnect the shift linkage
 

Jacket4life

Petty Officer 1st Class
Joined
Apr 22, 2010
Messages
382
Re: 74' 50hp water pump

There is no linkage to hold it. The driveshaft and the shift shaft are splined and fit into splined sockets. When they freeze up, it is usually b/c the lower unit leaked and fill up with water, then it sat for a while and rusted it together. usually if it drops at all it goes on off. If it is down 1/2 inch, you should be able to see the shift shaft at the front, you could spay the hell out of it with PB Blaster. Also, some ppl on here have hung them on stands or racks, then hung weght on the lower unit and gotten them to go that way.
 

Jacket4life

Petty Officer 1st Class
Joined
Apr 22, 2010
Messages
382
Re: 74' 50hp water pump

Oh, and what gear you are in has zero effect on it.
 
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