2003 280hp 5.7l Stumbling at lower revs

[Nicad]

Here are two symptoms of my boat's condition. When it is cold out, it takes a few cycles for the boat to stay running from dead cold...then it is OK. Probably three for four depending on how low the temp its. When warm outside it runs decently from dead cold. This is not really a big deal for me and it has done this for a few years now.

This year however I have noticed it is running rougher at low revs and also stumbles from getting on the gas from low speed. Perhaps they are related? Last year it also had all new OE tune up components. Cap, rotor, plugs, wires.

Is the fuel pump's operation something to check here? Power seems normal at higher revs under heavy throttle. Thanks if you have some theories on the cause. The boat has been well maintained and has 500 hours on it.

[Deephaven]

Hi Nicad,
I'm also having the same symptoms with my 7.4GI. What did you find out was your problem?