Re: 91 70 hp evinrude surges at half throttle need help
basic tune up including new plugs and draining the carb bowls would be a good start also check that the choke lever is in the right position and that the fuel bulb stays firm when pumped. when out see if the fuel bulb starts to collapse when on the throttle and if you can get a friend to pump the bulb when accelerating. if that doesnt find the problem then compression and spark will need to be tested to see how healthy the motor is.
as a florida boater you will find that its not all that uncommon to get a little water in the gas and the engine finds it hard to suck the gas in so it settles in the carb until it blocks/slows the flow of fuel. another problem seen in florida is a blocked fuel vent due to mud-dobbers which is why its worth checking the bulb to see if its being sucked in... i hope this helps
