1968 Merc 6hp Water Pumpimg Issues

[ragnar333]

This one's really got me scratchin' my head. I picked up a super clean old 6hp for cheap because it didn't pump water. I dropped the lower unit and took the pump apart. Everything looked great, and it actually looked like a recent impeller replacement. I chucked the driveshaft in a drill and ran it in a bucket and it seemed to pump pretty decent. I put it back together and ran it and it still didn't pump. I had dry exhaust coming out the port on the back of the stack.

I took it apart again and checked on the water tube. It appeared to be properly seated. I ran some compressed air into the tube to check for obstructions, and I didn't feel any air coming out the exhaust, but could feel it blowing back at me from somewhere inside the housing. Shouldn't air come out the exhaust port? Is it possible that the copper tube is split or rotted somewhere up inside? I really don't want to have to separate the powerhead from the stack if I don't have to. Any ideas?

Thanks in advance.

 

[ragnar333]

Re: 1968 Merc 6hp Water Pumpimg Issues

Nothing? LOL. Well I guess a better question is how much trouble can I get myself into if I pull the tube out to inspect it? What are my chances of reinserting it without disturbing the upper grommet in the powerhead?

 

[ddwilson]

Re: 1968 Merc 6hp Water Pumpimg Issues

I just finished a 68 6hp to test if plugged up make an adapter to go from garden hose to 3/8 tubing and attach to the copper tube if you open the flush port should get a good flow from it. make sure when you put the impeller in the little bar piece that goes along the flat section on the shaft is in there to turn the impeller. Replace the rubber bushing and washer in the top of the water pump so the tube will seal good into the pump. When starting make sure the water in the tank is deep enough to be above the pump not just the intake. If the pump is working good should get a pretty good stream from the hole beside the flush port

 

[ddwilson]

Re: 1968 Merc 6hp Water Pumpimg Issues

Also should probably replace the seal in the top of the pump housing.

 

[ragnar333]

Re: 1968 Merc 6hp Water Pumpimg Issues

Looks like I've got some issues. Both the flush port and the tell-tale hole are plugged pretty solid with corrosion/crud. I've got a feeling that this one's gonna need some intensive surgery.

 

[ddwilson]

Re: 1968 Merc 6hp Water Pumpimg Issues

Probably need to open the water jacket cover on the side of the motor and see how plugged up the inside is and pull the power head so you can clean out the flush port and tell tale