Overheating Issues/Popping out of gear

[Blake Hearn]

I have a 1971 18 hp Evinrude that i just replaced the water pump on. It is getting water through it but it is not a solid stream. After running wide open for a couple minutes it slowed down and eventually died. I touched the head and it was hot to the touch. When i run it slower than wide open it is not that hot. I was wondering if the water tube could be plugged and not allowing adequate amount of water to the head. It also tries to slip out of gear when running. If you give it about 1/4 throttle it will stay in place. The gear shift on the side is very very easy to move back in forth. When trying to go from forward to neautral it almost always go all the way to reverse. Any reply is appreciated.

 

[mikesea]

Re: Overheating Issues/Popping out of gear

you may have a defective thermostat,you actually heat seized it,you might want to check the compression,you may be lucky,but you wont get away with it much,it sounds like your clutch dog gear is begining to wear out,common in the older motors ,especially if you hard shift ,or the shifter goes back and forth to easy into gears.as for the overheating,if not thermo,it can be a salt or corrosion build up around the water passages,try pulling the thermostat ,check it by putting in cold water .then very hot and see if it opens fully,you can GUT the thermo if its bad ,just cut at the base of the two brass arms ,above the round guide for the plunger and cut the stainless rod at the top.that will allow a sufficent amt of water through with a bit of resistance,if the in and out of gear continues,which it will get worse,your going to totally trash the lower unit,I bet if you pull the drain plug you will see metal fagments,that means you need to totally dissamble and put a new clutch dog and likely a forward gear,possibly a rev.gear too.They are costly compared to value of the engine.you might consider buyiing a good used unit.But its hard to insure what you buy is OK.At this point,if I were you.Id pull the lower unit apart and see what you have.I do know its possible to machine the gear to once again mesh ,but you need a guy that can do decent machine work.I have done it with a dremel tool,but its up to you if you want to try it

 

[Blake Hearn]

Re: Overheating Issues/Popping out of gear

I took the thermostat out and ran it at the lake and it still overheats. It has a brand new water pump and i tried running a coat hanger up the water tube and nothing came out. I also took off the head cover (covering pistons) and checked all the holes around that. I have run out of ideas. I would really like to get this fixed before this weekend.