I am in need of opinions here before I spend any more $$$ on my
motor...

I have a 1999 Rinker with a carburated 250 HP MerCruiser 350. The
engine ran fine all last year, up to and including the day I had it
winterized. When I got it out this spring, it wouldn't start. It
wouldn't fire at all. I took it to a local mechanic, who replaced the
fuel pump, fuel filter, coil, and plugs. In a tank and in neutral, it
started and ran just fine.

Well, over the holiday weekend, I took it to the lake and dropped it
in the water. It started fine, and idled through the no wake zone
fine. However, it barely got on plane with just myself in it, and
maxed out at about 4000 rpm.

I had about 1/4 tank of old gas from last fall in the tank, so I
filled it the rest of the way with new fuel, and added a bottle of
octane boost. That didn't help - the engine actually started getting
worse. I thought maybe I had already clogged the new fuel filter, or
maybe had water in it (the boat was outside all winter) so I pulled
the filter and dumped out the gas, but it was clean and no water.

Finally, I tried carb cleaner, which was no help either. Now the
engine barely starts, and when it finally does, it maxes out at about
3800 rpm in neutral before cutting out real bad, and will not even get
to 2000 rpm under load. There is a very sight gas leak around the
fuel filter, but it is as tight as it can get, and the seal looks
good. The leak is less than a drop per minute... barely enough to wet
my finger after running a minute.

I'm baffled, and the 2 shops I called had no ideas either. Anyone
have any ideas before I take it to a different shop for another craps
shoot?