Spark advance symptoms

[Virginiaboater]

Greetings!<br />I hope everyone is having a happy boating summer. What would summer be without a boat in the water (or at least a motor to tinker with)?<br /><br />Anyway, I have a fairly specific question.<br /><br />I have a 1978 55HP 2-Cyl Johnson. I finally go the motor running well. My last obstacle was the spark advance plate/linkage. I didn't want to do it on the water because I didn't have anyone handy to drive the boat. I had a mechanic do it.<br /><br />MY question is: what would the motor do if the spark adavance's stop (the screw with the stopper and nut) were off a little on either side of the correct adjusment? You know, what would it do if it was a little retarded a too much, and what would it do if it was advanced a little too much.<br /><br />I've learned a lot about motors during the past four summers, and while most people pull their hair out because they have to work on their motors at all, I love that feel when you get everything tuned just right, and you feel the motor's power come back.<br /><br />Thanks for all your help.

 

[Silvertip]

Re: Spark advance symptoms

If the screw was set to allow too much advance, severe engine damage can occur. Too little advance affects wide open throttle performance. In other words it may not reach its power potential. One degree of extra advance may not be a problem, but two or three is asking for trouble. You probably wouldn't notice one degree too little advance. Two or three you probably would.