It's an older post but just came across it after searching because I just started experiencing same issue. A new boat to me, the maiden voyage was running great then lost power at full throttle. When i throttle down and open it up again, it surges for half a second then loses power again. If I hit choke, it also surges after a few seconds then loses power again. I haven't checked yet but almost positive it's trash in fuel system, probably in carb. I am going check filter in the next few days and if I see evidence of trashy gonna remove and clean carbs. The only thing that makes me thing I could be something else is when i disengage prop and throttle up, it doesn't lose power or sputter but of course it's not under load. Hopefully it's a quick fix though.. Btw it's a 2000 Palm beach 161 with a 70 HP Johnson.
