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Evinrude 4 hp 2 stroke overheating - please help

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kylewilliams

New member
I just bought an Evinrude 89 4 Hp 2 stroke engine model E4RCEC. It seemed to run Ok in the sellers garage in a barrel of water. When I got home I ran it in a bucket with water up to the cavitation plate, and in a few minutes it seemed to be overheating and died. Smoke was coming from the head unit and the screws that hold the cover on were very hot to the touch. (I had earlier sprayed some WD40 on the starter cord recovery spring mechanism and I am sure some dripped down on the engine parts. This could account for some of the smoke.)
I noticed that the water level in the bucket had dropped a bit, maybe 1/2 ”, below the cavitation plate, and that the water intake was up in the underside of the cavitation plate, so with that tiny drop of water level it must have started running dry for a short while. (other engines that I have seen have the intake on the vertical section of the shaft below the plate so a little dip in the water level is no big deal. My bad this time for not noticing!) It looks like the water outflow port is below the water line , no “pee tube” up above , so watching for water flow seems very difficult.
So can anyone please help me understand a few things. How do I check for adequate water flow on this engine? And was this short over heating enough to cook it? How can i tell if it is damaged? How much will these little guys take?
Also, I am assuming that previous owners of this motor have not properly ran the carb dry before storing so the carb is probably gummed up a bit. Short of disassembly and cleaning, is there an effective chemical cleaning strategy?
Thanks
kyle
 
You don't have to have water up to the cavitation plate only. You can have it way pass the cavitation and up to the exhaust port. You should be able to see water spray out of the exhaust port.
While running the motor, try to put your hand on the block (be careful not to touch the flywheel) to see if you jumps at it or can keep it there for 5-6 seconds. If you can then it's not overheating.
For used motor, you should change the impeller, service the carb, check the gear oil, etc... anyways before you take it out on the water. That old impeller can do ok a home, but at full throttle and on a long run, it may just become debris.
You can use carb cleaning fluid or brake parts cleaner to clean the carb after removed it, took the jet screw, idle screw, float and valve etc...out, blow all holes out with compressed air, brush it, do whatever to get the cleaning job done. Don't blow compressed air thru the fuel pump for you may bust a hole thru the diaphragm. You can loosen the screws on it and flush it out. Simple and easy. Search your model on this site and look at how things are set up, remove them and reverse them.
To determine if the damage is extensive after extremely overheated that toast the block, do a compression check...
Or bring to my shop and I help you out.
Good luck.
 
hello, thanks, I was afraid of that. good ;esson learned but i guess the impeller should be changed anyway. I will run a compression test to make sure there isnt any deeper damage, then procede.

cheers
kyle
 
Ok, I am a bit comfused now. I bought a compression tester, admitedly not the most expensive one, but when I tested my engine it showed 30 PSI in both cylinders. (the engine wouldnt start, but i pulled the cord until the guage stopped rising.) I ran the same test on another small OB engine I have and it readx the same 30 PSI. The service manual I have says it should be about 80-100. Are both engines bad, or did I get a dud tester? (please say I got a dud tester...)
thanks
Kyle
 
FYI I picked another comp tester and got 75 PSI on both cylinders on the Evinrude, and the same 75 on my new Nissan 3.5 that i know is OK. Can anyone tell me if this Is this range I would expoect from these small engines?
thanks
Kyle
 
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