1975 johnson 50hp/ no water to the powerhead

[Captmills]

I replaced the water pump and the impeller and had no water coming out of the slots on the back of the leg so I picked up a gasket and a thermostat and put those in and bought a plastic 55 gal. drum for a test tank and now I have water coming from all the right places but she was getting awful hot so I shut her down and pulled the cover off to see if it looked like water got to the powerhead and it did not seem that it did. Place a little red food coloring in the water jacket before I closed her up and ran again and checked with a pyrometer and she was running about 180 to 190 so I shut her down again and pulled the cover off and all my red food coloring was still there, Idea's, water tube maybe?

 

[Solittle]

Re: 1975 johnson 50hp/ no water to the powerhead

I suspect that your water pick-up is not below the surface of the water. best test it by backing the boat into the lake or wherever to assure that the pick-up is completely submerged. A 50 hp puts out a fair amount of exhaust gasses which may preclude use of a 55 gal drum.

 

[Joe Reeves]

Re: 1975 johnson 50hp/ no water to the powerhead

Assuming that the water pump functioned properly previously.... I suggest you drop the lower unit to inspect your pump installation. It's very easy to overlook something.

 

[Captmills]

Re: 1975 johnson 50hp/ no water to the powerhead

it had plenty of water and I had water coming out of all the right places, just not going into the head. Dang, I was hoping not to have to drop the lower again, oh well.

 

[5150abf]

Re: 1975 johnson 50hp/ no water to the powerhead

With the lower removed use your water hose or an air hose and blow it up through the pick up tube, if the air/water doesn't come out there is an obstruction, try blowing both ways.

Also make sure the pick up tube is below the drive shaft tube and as others have said the pump isn't self priming in that it won't suck water, it needs to be completely submerged to work.

 

[Captmills]

Re: 1975 johnson 50hp/ no water to the powerhead

note; always good to make sure the water tube is inserted into the water pump:redface:

 

[Joe Reeves]

Re: 1975 johnson 50hp/ no water to the powerhead

note; always good to make sure the water tube is inserted into the water pump:redface:

Yep, that goes a long ways in the cooling scenario.