Burned Water Pump Tube 1992 Mercruiser 3.0L Alpha 1 Gen II SNOD665768

[halcrimm]

As the restoration of my first boat continues this was the adventure of the weekend. Built a stand for the outdrive to make it easy to work on. Then went right to work. Drained the old oil (Which had a horrible smell, but it was black and had no milky discoloration) then separated the upper and lower unit. Started disassembling the water pump to change the impeller and realized that the water pump tube was not there. So I picked up the upper unit and looked in side to find the water pump tube still connected. When I pull it out I found that the tube had been melted pretty well. Obviously, I have to replace this tube but where else to you all think I should look for damage based on what I found here.

By the way the impeller was in pretty good shape. Replaced anyway. There was a pretty good size mouse nest in the cavity in the lower unit where the water comes in.

Appreciate all of your suggestions.
Hal

 

[Scott Danforth]

Re: Burned Water Pump Tube 1992 Mercruiser 3.0L Alpha 1 Gen II SNOD665768

i would replace the whole pump assembly and not just the impeller

 

[halcrimm]

Re: Burned Water Pump Tube 1992 Mercruiser 3.0L Alpha 1 Gen II SNOD665768

Good Morning Scott, I did but the kit that contains all new o-rings and gaskets. I did not get a new housing but as far as I could tell it was still in pretty good shape. There were no rubber burn marks inside the housing. It was actually very clean and shiny. there were also no dings, dents or corrosion. It cleaned up very nice. With that said do you still think I need to replace the housing also.
Hal

 

[jkm3093]

Re: Burned Water Pump Tube 1992 Mercruiser 3.0L Alpha 1 Gen II SNOD665768

I went through the same exercise last winter with my 94 4.3LX Alpha 1 Gen 2 and also found the plastic water tube melted and stuck in the upper housing:


It is only needed during assembly to guide the metal water tube into the pump discharge fitting, so it was of no consequence. Otherwise my outdrive was in good condition. Make sure you pressure and vacuum test the drive before re-installing!

 

[BajaDan]

Re: Burned Water Pump Tube 1992 Mercruiser 3.0L Alpha 1 Gen II SNOD665768

Hal,

I just replaced the water pump impeller in my 1992 3.0L Alpha One Gen II and the guide tube looked warped and burned just like yours. And like jkm3093 just said it's really only used as a guide during installation. I didn't replace or reuse my old one. Just make sure you have a helper to help carefully guide the lower unit into place and lubricate each end of the water tube. Also check your water shutter in the top of your lower exhaust elbow. If your motor was run with low or no cooling water (without muffs) then the water shutter can get burned and damaged. I found mine or what was left of it in the bottom of my lower unit. The water shutter keeps cooling water from back flowing up into the exhaust. It functions like a butterfly valve. Good luck!!!

Dan

 

[Don S]

Re: Burned Water Pump Tube 1992 Mercruiser 3.0L Alpha 1 Gen II SNOD665768

I wouldn't worry about replacing the housing unless it's worn. Being stainless steel heat doesn't bother it like the earlier drives with the plastic pumps. Those housings would melt and warp too.

That plastic guide tube melts easy, but the only way it melts if from lack of water. So when you put it back together, make certain your risers don't get hot. That would confirm water flow.