1984 50HP Mariner impeller change

Koffi

Cadet
Joined
Feb 3, 2006
Messages
20
My son has a 1984 50HP Mariner. He is in the military and is coming home in a couple of weeks. I want to change the impeller so he can fish as soon as he gets home. Can someone walk me through the process?<br /><br />Thanks
 

andy6374

Lieutenant Commander
Joined
Aug 4, 2005
Messages
1,617
Re: 1984 50HP Mariner impeller change

We sure can, but I highly recommend you get yourself (and then give it to your son) a mercury factory service manual. It will have pictures and it work through the entire process.<br /><br />Then you and your son can work through future projects together. You can usually find them on ebay. I got mine for $5 of ebay.<br /><br />Good luck and thanks your son for me
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: 1984 50HP Mariner impeller change

Time's an issue. Try your public library. Many have manuals. That's a very common Mercury configuration. Any manual that includes Merc will cover it.<br /><br />It's fairly easy to remove. The zinc trim tab above the prop has to come off to get to one of the fasteners. Otherwise you can see all of them. You won't need any special tools except maybe a big allen wrench for the bolt that holds the trim tab. You'll need an impeller and you should replace the base plate gaskets. If any of the plastic parts are melted, do a complete pump. <br /><br />Before putting the housing back on the pump, lubricate the impeller and housing with any thick soap (shampoo, dish soap, laundry detergent, etc). While turning the driveshaft clockwise, push the pump housing over the impeller. Getting the gearcase back on is frustrating to those that don't do a lot of them. That's where the manual will help.<br /><br />Good luck and feel free to ask any questions.
 

Boatwizard

Seaman
Joined
Feb 15, 2006
Messages
68
Re: 1984 50HP Mariner impeller change

Be careful when putting it back on. Check to make sure shift shaft is going together properly before tightening unit all the way up. If the shaft doesn't go in, you can force it up and break off a peice of the engine block.
 

sibylernie

Cadet
Joined
Apr 27, 2007
Messages
10
Re: 1984 50HP Mariner impeller change

I recently installed a water pump kit on my 50hp Mariner. It was much easier that I would have thought. One of the previous threads gave a good description of how to do the job. I would caution, however, that you take special care when installing the lower unit after the repair. The copper tube that extends down from the engine block to the impeller housing will not automatically seat properly. I actually installed the lower unit and then realized it may not have seated properly. I dropped the lower unit again and glad I did. The tube was not seated in the housing.

Good luck
 
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