1999 dt 140

[Dantheman]

I do alot of trolling with my boat.The engine has 150 hours on it .I try to use ethenol free fuel when ever I can.The motor acts like it is loading up while trolling for a few hours.It runs fine on the top end.I tried a tune up new fuel/water separator filter ,spark plugs and I ran a can of seafoam threw it.It did the same thing the next trip out.I am a Diesel Mechanic for a living and I work on all of my own stuff.If this was a carb motor I would think dirty low speed jets would be the problem but with EFI I am not sure? any help would be greatly apreciated {other than take it to dealer} thanks Dan

[conchycat]

motor not running right

You may try a new high pressure fuel filter. If your motor is like mine and has fuel injectors then a hp fuel filter pre to the injectors could fix the problem.