EvinrudeJohnson 15 overheating problem solved

[chetvaldes]

" The symptom was: it apparent

" The symptom was: it apparently just stopped pumping water and overheated. On inspection, it was found to emit exhaust gases from the tell tale, and then water from the tell-tale only when the thermostat housing was removed, and exhaust gases were seen to come out of the thermostat housing. The water pump was inspected, and the impeller looked like new, so it was put back together. The headgasket was checked and changed, along with the water tube gromment, which had closed up some and slightly melted. Still the problem persisted. I removed the exhaust cover and changed the gaskets, but it was obvious that wasn't the problem either. In a final attempt, I changed the whole water pump. Now it is working properly. I can't understand how the old pump is defective since it looks OK. I've seen seawater pumps on marine engines look completely worn out and still work OK, so I'm kind of perplexed by this. I wonder if there is a way to evaluate the water pump more thoroughly so one doesn't have to guess?
Chet "

 

[joereeves]

"Chet... Looks are deceiving e

"Chet... Looks are deceiving eh? Many outboard water pumps may look good as compared to other type water pumps (Jabsco etc), however they are a different animal so to speak. The impeller can take on a curl rather than have the blades snap straight outwards when removed from the housing. It may have picked up some sand or some other type abrasive material which has created a scoring in the lower impeller plate and/or upper housing. That scoring alone would have a tendency to create a air pocket.

Rule of thumb is: if the engine overheats and the water pump doesn't look like it just came out of the box, replace it.... then should the problem persist, go into the system as needed.

Joe

"