"Drew" wrote in news:1149787059.212252.307340
@i40g2000cwc.googlegroups.com:

could this be air getting in somewhere,

From the tank to the suction side of the primary fuel pump, including
those filters. I agree...air leak making bubbles in the fuel.

It's still leaking at higher throttle settings, but the injectors are
open further under the load so the same size bubble doesn't make as much
difference.

Idle it at the dock. Shut off the fuel valve on the tank. Let it run a
while or until it start to balk. Are the fuel filters still completely
full? Yes? (after the filter) No....the filter itself or before the
filter.

No, you can't fix a leaky hose by overtightening the hose clamps....(c;

Another possibility often overlooked.......

Run it until it starts to run like crap.
Unscrew the filler cap on the fuel tank.
Did you hear it sucking air around the cap, indicating the engine was
pulling a vacuum on the fuel tank because the VENT IS CLOGGED?

Damned Dirt Dauber Wasps, anyways....

Look on the boater's face who'd been looking for the airleak for months
when I found the dirt dauber's nest in the vent pipe?.....PRICELESS...(c;

Just enough air leaked around or through the mud nest to relieve the
vacuum after the motor had been shut down for an hour. Start the motor
back up, she ran like a jewel....well, until the fuel pump lost the
battle with the vacuum in the tank an hour after the next engine start.

Sound familiar??

When it starts to run like crap, crack open the fuel filler cap and see
if that smoothes it back out pretty quick. Vent clogged if it does.