Power loss after a few seconds.

[hybris1]

Already have more engine troubles on my new (to me) boat. 15 seconds or so after being up on plane, the power drops off. I hear some pinging and missing. This didn't make me happy on my first cruise. There was "another" engine problem that was "fixed" before I bought it. It had a similar symptom but I have to admit it might be different. That one the knock sensor was being tripped by a bad gimble bearing. Unplug the sensor and the problem went away. This time the engine is losing power. The idea I just came up with is that the fuel tank vent is plugged. This would starve the engine of fuel and explain why it working fine on the sea trial just a week before. The one variable between the sea trial and my first cruise is that I filled the tank (47 gallons). I can't wait to get off work and go check the vent line. I just wanted to get any other ideas that you may have. Thanks.

Engine: 1998 5.7L carbureted/bravo II

[seapuppy]

also check the fuel filter...I had one that did the same thing...a small piece of garbage would block enough fuel that it would run just fine and then when pwr was applied it would go up to rpm and then die..ping..rattle...cough..sputter...drop the throttle back and it would idle fine again....there should be an inline fuel filter check that....oh heck ..just replace both of them....the spin on and the inline.....

[hybris1]

There is just one filter on mine and I did replace it.

[Maxum2300SC]

did you fill up recently, water in the gas?

Just re-read your post you did fill up, how much gas was in it before hand?

I and many boaters ran into this 2 years back after filling up for the first time in the season, basically had to burn the whole tank and fill up fresh, something with the mix of the 2 gases. The gas that was in it when I filled it was non-ethanol, and the gas I put in had the ethanol. I think thats what I determined to cause it.

But it would spit and pop, no power and I changed everything, plugs, filters ect and none of it fixed it. After burning it all I refilled and was fine.

Also not sure if when your state started using or even uses ethanol in their gas but the ethanol in the gas mixes with water easier, so for instance If you had a tank of gas before they used ethanol in it the water would not mix at all the gas (if you had water in your tank) and it would sit at the bottom and you would never know it. Put a tank of gas with ethanol in it and the water mixes more so with this bringing that water into the flow of gas...Just a thought