Old 5hp johnson and black spark plugs...

[rebel duck]

the motor runs like a top when new plugs are in, but it only takes 2 or 3 trips to the lake to blacken the plugs and make the motor start to sputter..am I putting in too much oil with my gas? I am going with a 50:1 ratio because I don't really know what this motor requires. The motor is so old it doesn't have a twist throttle and no neutral. Should I increase to 100:1? Some thing has to be done, I'm going through spark plugs like theres no tomorrow. Any help would be great............RD

 

[JB]

Re: Old 5hp johnson and black spark plugs...

Howdy, Rebel duck. My guess is that your engine is older than dirt and the rings are worn out. If your compression checks at less than 80lb, sell it to an antique collector and get yourself a more modern motor. . . say, only 40 or 50 years old.<br /><br />If you insist on keeping that one in service you might try a hotter plug.<br /><br />That engine was probably intended to run on 16:1 or 32:1 mix. Loosening clearances and TWC3 oil have kept it alive at 50:1. Don't try 100:1 or you will risk seizure.<br /><br />Good luck.<br />JB