4hp Evinrude Yachtwin Overheating

[elrw2]

This 1973 motor is overheating for some reason. I am getting some water through the exhaust ports. The water pump looks fine with not blades missing on the propellor. I blew air up the water intake tube and that appears fine. Any suggestions before I disassemble further, or reassemble and try again. I am afraid that running it hot too many times may hurt the little engine. It has very few hours. Any help is appreciated. Thanks.

 

[JB]

Re: 4hp Evinrude Yachtwin Overheating

Howdy ELRW.<br /><br />Running too lean or with ignition too far advanced may cause overheat (or melted pistons).<br /><br />Use a factory manual to adjust the carb and the ignition synchronization.<br /><br />Good luck.

 

[DJ]

Re: 4hp Evinrude Yachtwin Overheating

I believe that engine may have a thermostat.

 

[Chinewalker]

Re: 4hp Evinrude Yachtwin Overheating

Actually, the motor should not have a thermostat.<br /><br />I would replace the impeller. It may be old and have taken a bit of a set or gotten too soft to pump properly. Also, make sure it's not sucking air around the base of the pump housing or pump plate. Impellers are cheap - motors are not.<br /><br />- Scott

 

[elrw2]

Re: 4hp Evinrude Yachtwin Overheating

Thanks for information. I will reassemble and try the motor with the new propellor. I will also enrich the fuel mixture. I have been using a 40:1 mixture, as opposed to the factory 50:1 to try and prevent any massive damage. I will seal the pump fittings to prevent any possible air intake. Hopefully all will go well. The motor has very few hours for a 1973, but I do not want to ruin it now. Thanks again for your input.

 

[Buckstar]

Re: 4hp Evinrude Yachtwin Overheating

hi, you might have to remove the exhaust cover and check the water passage, sometimes that passage gets plugged with salt and restricts water flow.

 

[Chinewalker]

Re: 4hp Evinrude Yachtwin Overheating

Personally, I would leave that motor at 40:1, as it has babbit bearings at the rod journals and lower and middle crank journals. I've got quite a few busted up 4hp blocks from rods getting tossed out. Little extra oil won't hurt it at all....<br />- Scott

 

[elrw2]

Re: 4hp Evinrude Yachtwin Overheating

Thanks all for the information. I will take the exhaust cover off to be sure there is no obstruction. Thanks Chinewalker for the advice on the oil/gas ratio. The little motor does not smoke, but I wanted to be a little extra cautious.