72 Mercury 50 horse impeller replacement

S

skullie

Cadet
Joined
Oct 6, 2011
Messages
17
Help! First time working on a Mercury, I have no idea how to drop the Lower unit. Does anyone have the breakdown?

Thanks
 
I

impatico

Petty Officer 2nd Class
Joined
May 24, 2010
Messages
184
Re: 72 Mercury 50 horse impeller replacement

one nut on either side, loosen then evenly as there isn't enough room to do one at a time. then there is another by the trim tab. there is a little metal tab to pop off then it takes a allen bit to undo the bolt in there

thats is, just the 2 nuts and a allen bolt
 
fisherguy123

fisherguy123

Petty Officer 1st Class
Joined
Dec 17, 2010
Messages
333
Re: 72 Mercury 50 horse impeller replacement

hi....my motor is a 1982...merc 50 and very similar to yours ,I replaced the impeller on it this past June. It was the first time I worked on this motor and simple to do. The hard part is getting the shifter shaft splines to line up on the re-assembly ......you want to be sure the motor is straight up and down and an extra set of hands to start the nuts is helpful while another holds the lower end up in place. You may have to turn the flywheel to get the shifter splines to engage. I was able to to the job myself but it took 4 tries to get it all up in place properly.
You may have to rebuild your water-pump if there is any internal scoring and replace all the "o" rings and gaskets. ....good luck
 
S

skullie

Cadet
Joined
Oct 6, 2011
Messages
17
Re: 72 Mercury 50 horse impeller replacement

I may have a bigger problem...the wiring harness where on the engine is rotten. where it plugs into the side. anyone know a part number or approximate cost?

Thanks
 
C

carholme

Rear Admiral
Joined
Sep 4, 2010
Messages
4,845
Re: 72 Mercury 50 horse impeller replacement

Scott;

Here is the parts list for your engine:

http://www.crowleymarine.com/mercury-outboard/449.cfm

Check under "STARTER MOTOR, STARTER SOLENOID, RECTIFIER AND WIRING HARNESS" and see item 32. They have it dor sale or you can google the p/n to see if you can find another. Be careful of some of the ridiculous prices out there.

Gerry
 
S

skullie

Cadet
Joined
Oct 6, 2011
Messages
17
Re: 72 Mercury 50 horse impeller replacement

Ok...I'm back. changed the impeller, still no water, the drive shaft was pitted and rusted around the the impeller housing. cleaned that up a bit. and the housing looks worn where the drive shaft comes through and water leeks right out. Will a new housing fix this or will the rust cause it never to seal?

Thanks
 
F

FLATHEAD MAC

Petty Officer 2nd Class
Joined
May 11, 2009
Messages
116
Re: 72 Mercury 50 horse impeller replacement

Is it possible that the shaft key was not installed. That hlods impeller in place just asking, could be blockage between tell tale hole and water pump, with lu off back blow with compressed air from telltale back thru pipe that connects to water pump. And take a shoret piece of weed eater line or simmilar and prob the tt hole
 
M

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
Re: 72 Mercury 50 horse impeller replacement

Need to install ss sleeve on the shaft. Very common on carbon steel shafts. been there done that.
 
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