Okay about our 1978 Johnson 115hp motor.....we checked the compression and it is fine. I posted a second question under another one of my other topics. The problems we are having started when my husband pulled the plugs on our motor and cleaned them up. He put the plugs back into the motor and now the motor backfires throught the exhaust when we try to start it (not everytime but most of the time). My husband says one of the cylinders is missing. He did not gap the plugs before he put them back in as he did not think he moved them any. Anyway I want to know if this could be the problem...............