"Drew" wrote
could this be air getting in somewhere,


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


If it were the injectors, there would be some smoke from the
exhaust when the problem was occuring, wouldn't there?


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.


Hmm, but it would also be pulling a higher vacuum on the
fuel system, and probably pulling in more air, I would
think. It may run more smoothly but surge somewhat due to
the uneven fuel burn.



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....

Wouldn't it be just as easy to check the vent?


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.


And it's hard on the fuel pump & injector pump.

Since this is a Lehman, you're in luck. Call American Diesel
in Kilmarnock, Virginia. They know more about these engines
than everybody else in the world put together. They're also
friendly & helpful folks.

Fresh Breezes- Doug King