overheating

[boatwrecker10]

1978 johnson seahorse-4 hp air cooled motor overheats and runs rough and wants to stall. i take off motor cover and it runs fine. i was told the cause was not enough oil in fuel mix. can anyone advise of correct mix? also, what is correct mix for 1983 johnson 7.5 hp?

 

[samo_ott]

Re: overheating

Is it a 4hp or a 7.5hp? Although all engines in the 70's are 50:1 tcw-3 oil.

Are you sure it's air cooled? I wasn't aware that J/E made air cooled 4 or 7.5's, I though they were all water cooled.

 

[boatwrecker10]

Re: overheating

the 4 hp is air cooled,i'm sure. i have another motor, the 7.5 hp, and wanted to know if the mix was the same.

 

[Rick.]

Re: overheating

OMC 1978 4HP is water cooled. Check your compression and as long as it isn't buggered get a new impeller for it. These a great little engines. Best of luck. Rick.

 

[bustermin]

Re: overheating

iI am not familiar with that motor, but i know some motors have an exhaust tube that can leak and if the cover is on the motor cant run due to exhaust getting in the motor, and then when the cover is removed it can get fresh air and it will run fine. like i said im not familiar with that motor but you might check it.