2015 Mercury 115hp 4-stroke

by Kim
(Florence, SC)

Starts great. Can run for 5 minutes or an hour then it will start sputtering. The steering wheel snatched and the motor jumps when this happened. No alarms. If I turn the boat off and on then it will fix it for another 5 minutes to an hour then it starts stuttering again. I’ve taken it to a mechanic and they can’t pinpoint the problem no it won’t sputter when they are on the boat so they can’t pick up the problem in their computer. Spark plugs have been changed twice. Put in ‘heat’ treatment in the gas to pull out any water. We use Sea foam as well. Nothing helps. Level of gas doesn’t seem to matter... it will sputter with a full tank as well as empty. Any insight would be greatly appreciated.