Need help with a motor issue

[Accorsi]

Hi everyone. I have an Allison Grandsport with a 2000 Merc 300 drag. The last handful of times I have used my boat this has happened About Half of the time. Going along at 5mph everything is fine, I press the gas and it almost feels like I’m running out of gas. Basically stalling out, and if it doesn’t stall And I plane up engine will even start to knock. I’ll try to plane up multiple times with the same result and then sometimes after the 3rd or 4th try everything runs normal. My local marina is not sure why it is occurring And unfortunately I’m ignorant in this department. Any help or suggestions would be greatly appreciate. Thanks

 

[stuart gary]

clean out the little hose usually clear or black coming from the computer. sometimes if its plugged the computer isn't reading right and the engine doesn't want to function. however if it starts to knock you may have other issues