I'm almost afraid to ask this question for fear of what answers I might get
but here goes:

My boat has a Volvo Penta 5.7 GS engine (carbureted) with 240 hours on it.
It is very well taken care of. Today as I cranked it up, I let go of the
key before the engine caught on and from the sound of things, I knew what
had happened. The engine actually kicked backwards one stroke and sucked up
some water.

I figured, "no problem, this has happened before and I can handle this." I
took out all of the plugs and cranked the engine to let the water blow out
of the cylinders, dried the plugs and put them back in and proceeded to
start the engine.

The engine started but there was a pretty loud knocking sound. I shut it
down to check my plug connections and to check to make sure I had not mixed
up and plugged the wires back in the wrong order and everything was okay. I
started it once again and still had that darned noise.

Any ideas?

I'm really nervous about this one.

Frank