Bad fuel.
Change fuel separator.

"Terry" wrote in message
...

My boat has a 1997 Volvo 4.3L engine. Since the start of the season it
has not run well. It is low on power and seems to sort of sputter. it
still works, it'll pull skiers and whatever, but it definitely has
less power than it did last year. Odd thing, while running along it
will all of a sudden start running right, then back to sputtering,
then back to right. At it's best it will run maybe 10 seconds bad, 2-3
seconds good, then back to bad. Sometimes it just runs bad all day,
other days it's back and forth.

I checked the plugs, they all looks the same. I was thinking if one
was different it would suggest one bad cylinder. Dist cap/rotor look
ok, checked resistance in the plug wires and didn't find anything
unusual.

Other than start replacing parts I can't think of what to do. Not even
sure what to replace after plugs/wires/cap/rotor.

One possible clue: I replaced the intake manifold in the spring due to
freezing damage. The engine was drained but apparaently a little water
was left in the manifold. From the help I got on this newsgroup that
is apparently a weak spot with these engines.

Where to look? Any diagnostic suggestions?

Thanks for the help,

Terry