I went out today, first time since last spring. 25hp Nissan motor has sit covered outside with motor down (Well Drained over winter) because of Illness. It started and seemed to be running fine, squirting water ok. Took off from ramp area and it was real sluggish and died. Not a good smell from it. Restarted and it did the same thing only sooner! Still smelling, took cover off and it was red hot but not seized up. It had been squirting a good stream of water. Trolling motored it back in and took home. Looking at it closer it was not pumping water apparently through the upper portion of the water jaket, can tell by where the paint scorched off. Motor will still fire, start and run, used it to load on trailor at boat ramp for just a minute.
I do have muddobbers and lots of the Japaneese beetles, am going to have to open the water jacket and probe for that if no one has better ideas. I am baffled as to why the thing squirts a good stream and not going through the upper cylinder, head area and down and out the lower discharge area.
Does any one have any experience with this type of problem. The next thought is the water pump is weak, but I would not think the pump would just get it high enough to Pee out the side discharge and not push it up the next 6 inches. Someone said it might be a thermostat, I would not think a 25 hp nissan would have a thermostat. Does anyone know if it does have one and where is it located if you know. Thank You!

