Hey guys, I am new to this group so any input is greatly appreciated. I have been having this issue for about 2 years now. Its a bit of a lengthy description but this is what I've got. Motor will do great starting, idling, and running until pushed towards WOT then will drop RPMs over time momentatily then regain them until eventually "bogging" down completely and running full throttle gives me roughly 10MPH. Some trips out this issue will not present itself especially if I have my wife and son in the boat and I'm running a little slower. Making me think something is heating up and causing the issue. However, I had my father out flounder fishing and we were half throttle because of wind/waves and it eventually began. Its a 18ft tunnel hull so my RPMs are a little low for the motor at WOT getting me around 5000 if I'm really pushing it and trimming up. Normally once it starts acting up I'm around 4200 and it will drop to 3800 then pick back up within seconds then start again and again until eventually going down completely. At first I was thinking fuel so I cleaned all 3 carbs, changed spark plugs, and cleaned fuel filter Problem persisted. I also have primed the fuel ball when it is happening to try and eliminate the fuel pump and nothing got better. I then took it to a mechanic and he did compression checks, cleaned the carbs, and changed my fuel line and ball from tank to quick disconnect. Problem came back. Ran a external tank with different quick disconnect to eliminate my tank and lines and still persisted. So now I'm leaning towards anything else, changed thermostat and water pump (just because) then changed all power packs and ignition leads. still have the issue. I know my overheat sensor and low oil will put the motor in limp mode but with a alarm. Alarm works as I get that sometimes when running shallow or sucking mud up for for duck hunting. Any help is greatly appreciated I'm starting to run out of ideas.
