evinrude 120 cooling system problem, need help!

[ifishing]

i have a 1993 evinrude 120 outboard, just replace the water pump, but seems the water pump not working good, when i start the moto in idling, i can see Small water column flow from the moto right side end, but when i run forward in three or four mins, the water column can't be seen and seems the water pump not working any more, then i stop the moto , i use water Reverse Flush many times and restart the moto , the pump work again, but can only work in idling mode, once forward or backward, the water pump stop,and the water column can't be seen again, anyone can tell me what problem is it? thanks in advance!

 

[Bosunsmate]

Re: evinrude 120 cooling system problem, need help!

Did you put the impeller key back in and the right one for the impeller you bought?
Try it on muffs in forward to see if the lack of back pressure from exhaust when out of water improves the flow while in gear

 

[ifishing]

Re: evinrude 120 cooling system problem, need help!

Did you put the impeller key back in and the right one for the impeller you bought?
Try it on muffs in forward to see if the lack of back pressure from exhaust when out of water improves the flow while in gear

thanks a lot Bosunsmate, the water pump was installed by Evinrude dealer, so i have no idea about it . today i try again, start the motor, in idling the water pump works good and water flow is strong, but when i move forward, less then 200 meter, the water flow becomes weak, i stop the motor at once so the motor not over heat, i use my trolling motor to back to my dock, i use water Reverse Flush the way water flow comes out, restart the motor the water pump work again, so Strange.

anybody can help ? so worry...

 

[Bosunsmate]

Re: evinrude 120 cooling system problem, need help!

You need to try that out of the water on flushing muffs.
It may be a leak in the exhaust gasket pressurizing the waterjacket at increased rpm or it may be the headgasket leaking with combustion getting into the waterjacket.
Testing on muffs will tell you which one is more likely- unless its something else....

 

[Fed]

Re: evinrude 120 cooling system problem, need help!

I'd be checking the impeller key even Evinrude dealers make mistakes.