TOPIC: Water Tube Sealant

The goop that is was used to seal around the water tube and the pump housing is brittle and starting to fall away. What should I do if anything? I was thinking of chipping it all off and using M3 4200 or something to reseal it.

Obviously, you are working on an old motor because the housing pictured is metal & has a seal on the top. Maybe I am wrong with what I am about to write, but it holds true for the past 40 years or so.

The copper tube should stay in the tower housing. How would you ever install the lower unit & get that inserted into the top end correctly???

There is no goop there, just a rubber tapered seat in the outlet of the pump. Mercury used a plastic guide tube about 3" long that fit into the water pump outlet perhaps 1/4" until it touched the top of the rubber tapered seat. Then when installing the lower unit, the copper tube goes into the plastic guide as you install gearcase. Everything in theory just goes together at that point.

I believe that goo you see is a melted guide tube from the engine running without cooling water & the exhaust melted it. If that was a plastic housing, it would be melted too.

that is correct.

Interesting. I replaced the impeller before I ran the motor for the first time after I got it. I seem to recall that plastic sleeve. But I've never run her without water even for a few seconds. And the motor was always cool to the touch.

Take a look at this shot. I remember when I was putting the new impeller in I thought it was too big. So I worked it in. Is it possible that it was too big and the friction was heating the housing up to the point that it melted the sleeve?

I am wondering what the black plastic is higher up on the copper tube in the 1st picture. Is there a guide tube up in the tower housing too on those old Merc?

Regardless, that impeller is the correct size. As for "working it in", the best way to install an impeller is to put a film of grease in the housing, push the housing down onto the impeller while turning the shaft CW (looking down). The vanes will fold back & the housing will slip right into position.

You need to clean the old melted plastic off, verify the tapered seal is OK or replace it & install a new guide tube. I also put a dab of grease onto the end of the copper to help it slip into the rubber seal.

do your self a favor and get a kit has all the parts needed about $30.00 on ebay.NOW