think this will do it?

[howsab0007]

I have an 85hp evinrude (1976) model#856930 serial#j0007213 motor runs great at idle and really has a good take off it will reach max speed... BUT once it levels off it looses power and starts to surge (but never dies) just put in new fuel tank,primer,and fuel line. but didnt change anything...could it be the coils getting to hot and if so how can i check? i have all the meters and tools just dont know where to start...

"UPDATE" I CHECKED THE 4 COILS 3 HAD GOOD FIRE 1 WEAK FIRE COULD THIS BE A PROBLEM???

 

[Solittle]

Re: think this will do it?

It could be a weak coil but it could also be air getting into your fuel line, perhaps some water, crud in the tank, tank pick-up or carb. To eliminate a fuel delivery problem take along a spray bottle of pre-mix and sspray some into the carbs next time it starts surging. Have you checked the ignition wire & spark plug on the cyl with the weak spark?