man this is a great site!! glad i found it--here is my situation. My boat gets used a-lot!I fish in it 3 times a week and motor has been purrr-fect since i can remember. made a 3 mile run back to the launch at WOT and motor ran great as always,re-started it to load on trlr,wouldnt stay runnin??? seemed to 'cough' intermittenly and would only run with idle lever all the way up.I checked for firm fuel primer bulb,was ok,watched it run a second and noticed that when it 'coughed' it blew exhaust only out of the water spouts and it seemed to be a rather strong 'blow'; then the water would return to normal flow(not talking about tatle-tale water stream;motor is not equipped with it)---run a second--cough--run a second--cough.I think this is a back-fire through the exhaust side? Pulled the plugs,nothing unusaul, good color,no fouling.Suspected bad fuel-got another fuel cell and fresh,quality fuel--same result.Was able to get it in gear and on plane with a lot of well timed choke engagments,but problem returned as soon as i started pulling back on the throttle.cant tell for sure the year of motor ,has a 1976 sticker under hood on air silencer but numb. comes back a 1978. It does have four coils,and a single power pack. I/ll be checking compression in the A.M. for sign of blown head gasket.thanx for the help, im sure i left somethin out, just let me know!
