1960 Evinrude 40hp, won't pump H20!

[Northdoc]

I have inherited a 1960 Evinrude 40 in great shape. I overhauled the carb & fuel pump, re-sealed the gearcase & replaced the H20 pump impeller. Runs great, but the powerhead gets too hot after a couple of minutes running in a barrel. I pulled the gearcase back off & stuck it in the water with a drill motor on the driveshaft. Ran it clockwise on high speed & no water out the tubes. All in the lower unit seems fine & all passages open. I have replaced many impellers on different makes & models over the years, but not on a 2 pipe recirculating system. How does this system work? Does water go up both tubes coming from impeller housing? Does water come back to the impeller housing down one of the tubes? Seems like I should get SOMETHING out of the housing with the drill motor, but nothing? HELP!!!

 

[bktheking]

Re: 1960 Evinrude 40hp, won't pump H20!

Obvious one, pull the pump housing back off and look to make sure the key is still in place for the pump, I've had them jump out putting them back together and discovered the key on the bench. When you do so many of them as stated sometimes the brain can play tricks!

 

[F_R]

Re: 1960 Evinrude 40hp, won't pump H20!

Water from the pump goes up one tube and circulates through the powerhead. The thermostat then takes a look at it and decides whether or not it is warm enough. If it is not warm enough, the 'stat stays closed, sending the water through a pressure relief valve and the second tube, back down to the water pump for recirculation till it gets warm enough.

Then the thermostat opens and the hot water is discharged and the pump sends up some more cool lake water to repeat the cycle. This is a continual process, the 'stat constantly sampling the water and opening or closing as necessary to control the temperature.

So, with all that in mind, is your thermostat and relief valve all in place? When you were running it with a drill, was the return to the pump under water or was it sticking up where it could suck air? When you were running it in the barrel, was the pump submerged?

 

[tx1961whaler]

Re: 1960 Evinrude 40hp, won't pump H20!

That motor has to have the leg submerged halfway up in a barrel before it will pump water reliably.

 

[Northdoc]

Re: 1960 Evinrude 40hp, won't pump H20!

AHA! Makes perfect sense. I had the pump above the water level and both tubes in the air. If I submerge both tubes and the pump, should one of the tubes pump & the other draw? Where is the check valve? I installed a new stat & checked the ball & spring under the stat, seemed OK (is this the ck valve?) Thank you for the reply, very interesting & informative!

 

[Northdoc]

Re: 1960 Evinrude 40hp, won't pump H20!

Yup, checked & key in place. I think the reply from F R is the ticket! Thanks for the reply.