I'm new to these boat motors, I have a 1969 55 Horse Johnson 3cyl motor. It has fuel going to it but will not fire. I took a plug out and grounded it to the motor tried cranking and I do not see a spark, while cranking. Sometimes as I turn the key off I will get a spark, and the last couple of times I got a backfire as I turned it off. The main wiring harness is a bit abused and wires have some bare spots(which i have covered with black tape. I'm new to this and would like to know where to start.<br /><br />Thank you Don 