1975 Evinrude 50hp pumping water but still overheats

[Scotty buckshots]

Hi I have a 1975 Evinrude 50 hp new waterpump kit it pumps water hard alot out of the exhaust and back of the leg but still overheats I don't think the water jacket is filling up I removed the tsat and still wouldn't fill up any advice? Thx

 

[SCduckhunter]

Re: 1975 Evinrude 50hp pumping water but still overheats

Welcome,....as far as I know these motors have upper water tube grommets...usually this leads to an overheat even with a good water pump and impeller..they are located at the base of the powerhead where the exhaust housing mates to the powerhead...one is on the long copper tube that's the water inlet from the pump..the other is on the short copper tube,thats the exhaust or hot water.....if either is plugged or deterioted they won't allow for proper water flow..either volume into water jacket or to expell hot used water..they are like 6$ each and replace the gaskets as you got....honestly I had never done it before and repaired/replaced entire cooling system from top to bottom in less than 8 hours...including removing and resurfacing head and replacing gaskets....best advise..have all your parts before you begin..it took me 3 weeks to get a few due to them being back ordered..

 

[SCduckhunter]

Re: 1975 Evinrude 50hp pumping water but still overheats

Welcome,....as far as I know these motors have upper water tube grommets...usually this leads to an overheat even with a good water pump and impeller..they are located at the base of the powerhead where the exhaust housing mates to the powerhead...one is on the long copper tube that's the water inlet from the pump..the other is on the short copper tube,thats the exhaust or hot water.....if either is plugged or deterioted they won't allow for proper water flow..either volume into water jacket or to expell hot used water..they are like 6$ each and replace the gaskets as you got....honestly I had never done it before and repaired/replaced entire cooling system from top to bottom in less than 8 hours...including removing and resurfacing head and replacing gaskets....best advise..have all your parts before you begin..it took me 3 weeks to get a few due to them being back ordered..Oh when you have it torn down, use compressed air to blow out water jackets from around the block...this will remove any debris from leaves dirt and silt to small pieces from a broken impeller

 

[Scotty buckshots]

Re: 1975 Evinrude 50hp pumping water but still overheats

Thanks how do I get to the copper tube that runs up the leg to the thermostat the motor runs excellent 150 lbs compression both cylinders shifts great and good spark. I got it for free but the catch it has been sitting for 7 years. I don't get why the water would be pumping so good out of the motor but not cooling the head down could the passage way in the water jacket be clogged or does the water have to flow threw there to exit the motor ?

 

[Scotty buckshots]

Re: 1975 Evinrude 50hp pumping water but still overheats

Should there be a grommet between the copper tube and the waterpump housing where it connects or just at the top?

 

[iwombat]

Re: 1975 Evinrude 50hp pumping water but still overheats

Before you go pulling a powerhead to check the tubes, maybe you should check some easier things first. Like maybe the diverters in the head.

What makes you think the water jackets aren't filling up?

 

[SCduckhunter]

Re: 1975 Evinrude 50hp pumping water but still overheats

On a lot of the water pump kits the grommet at the base of the water tube on top of the impeller housing is included....the tell tale or pee stream is diverted before the water enters the powerhead it is fed almost directly from water pump...in my experience when a water pump and thermostat has been replaced and looked over and an overheat situation is still occurring its usually the grommets at base of powerhead..you can try to remove the elbow fitting( careful is plastic) where the tell tale hose connects at the water jacket..drop the foot and blow compressed air through it..anything hindering the flow and stuck in the tube should blow out especially if old impeller was missing any pieces..unless it traveled further into system..however..the K.I.S.S. method is usually best...work from the outside in..start with the easy stuff and move deeper until the solution is solved..


To get to that water tube you're going to have to drop foot and remove powerhead...you can also look up,a water flow diagram for that motor and that will help,you understand the way the cooling system works..they are all different from model to model

 

[Scotty buckshots]

Re: 1975 Evinrude 50hp pumping water but still overheats

Hey thanks for the help guys the copper tube had a crack I just slid a rubber hose to the top of it works great thanks again