I have a 28 foot walk-around with dual chevy 350 inboards, velvet 71-c
transmissions and 16x18 props. Loaded weight is probably about 12,000.

The port engine will rev all the way up to 4200/4400 rpm at WOT and will
cruise in the 3200-3600 range. The starboard engine maxes out at 2800
rpm and won't go beyond that under load.

Both engines rev-up equally in neutral and compression tests were fine.
Had the boat hauled and the bottom and running gear are clean.

Any thoughts as to where to look for the problem?

Fuel starvation. Filter plugged, pinched hose, tank screen clogged,
air leaking into suction side of the line before the pump, fuel valve
closed partially when the wife hit it putting her beach bag in the
bilge. It'll run fast with no load because it doesn't use enough
fuel with no load.

If it'll run fast when you start up and gradually loses power, check
the tank vent for bug nests or other clogged air vent crud.

It's runnin outa gas under max load.....

It's not legal to install a primer bulb in an inboard (like the one in
mine) but it's the greatest fuel system troubleshooter made. If you
don't want to leave it inline, make up a little connector hose on the
inlet side of one and temporarily install it between that big, honkin'
Racor fuel filter and the Racor's outlet hose. Leave the motor cover
on the dock and go for a ride. Let someone else drive it while you
watch the bulb. If the filter or fuel line before the bulb is
clogged, the bulb will collapse as the engine sucks harder and harder
trying to get fuel....pretty simple, eh?

If the bulb doesn't collapse and the engine bogs, try pumping the bulb
by hand to see if the engine comes back to life. If it does, your
fuel pump is toast! You can actually feel the fuel pump humping
against your hand squeezing the bulb. If the intake valve on the fuel
pump doesn't close, it'll actually bulge the bulb. If the fuel pump
fails, the bulb is also a great way to get home by having some slave
pump the bulb to replace the fuel pump.

Run the boat until it bogs and shut this engine down out on the water,
quickly. With the now-shutdown engine off, pump the bulb and see what
you "feel". Because the fuel pump had pressure on the carb and the
carb should already be full of fuel, the float valves should all be
closed, already, and you'll not be able to pump more fuel into it.
The bulb shouldn't pump at all, but be impossible to squeeze down.
It'll feel hard. But, if you can pump the bulb, either the carb float
valves won't close or the fuel pump diaphram has a hole in
it....probably the latter as we're experiencing fuel starvation.
(Crankcase oil smell like gas on the stick? That's where the gas goes
if it has a mechanical fuel pump.)

It's not rocket science. Keep the bulb and hose on the boat. You
never know when you might need it to replace a bad fuel pump or
troubleshoot the problems 18 miles from the dock! I've loaned out my
bulb to stranded boaters many times.....without having to tow them
home.

Oh, you DO have that big honkin' Racor, don't you? No? Then add
another source of trouble to this list......The carbs are full of crap
and water which gets sucked up into the tiny holes when you goose it.

Why a $30+K boat doesn't already COME with a proper fuel filter
remains a mystery. It's almost as if they WANT them to fail!



On Mon, 18 Aug 2003 08:10:30 -0400, John M Murphy
wrote:

I have a 28 foot walk-around with dual chevy 350 inboards, velvet 71-c
transmissions and 16x18 props. Loaded weight is probably about 12,000.

The port engine will rev all the way up to 4200/4400 rpm at WOT and will
cruise in the 3200-3600 range. The starboard engine maxes out at 2800
rpm and won't go beyond that under load.

Both engines rev-up equally in neutral and compression tests were fine.
Had the boat hauled and the bottom and running gear are clean.

Any thoughts as to where to look for the problem?


Larry W4CSC

Maybe we could get the power grid fixed if every politician
regulating the power companies wasn't on their payrolls.

Check the timing also.
Bill

"Larry W4CSC" wrote in message
...
Fuel starvation. Filter plugged, pinched hose, tank screen clogged,
air leaking into suction side of the line before the pump, fuel valve
closed partially when the wife hit it putting her beach bag in the
bilge. It'll run fast with no load because it doesn't use enough
fuel with no load.

On Mon, 18 Aug 2003 08:10:30 -0400, John M Murphy
wrote:

I have a 28 foot walk-around with dual chevy 350 inboards, velvet 71-c
transmissions and 16x18 props. Loaded weight is probably about 12,000.

The port engine will rev all the way up to 4200/4400 rpm at WOT and will
cruise in the 3200-3600 range. The starboard engine maxes out at 2800
rpm and won't go beyond that under load.

Both engines rev-up equally in neutral and compression tests were fine.
Had the boat hauled and the bottom and running gear are clean.

Any thoughts as to where to look for the problem?


Larry W4CSC

Maybe we could get the power grid fixed if every politician
regulating the power companies wasn't on their payrolls.