[OMC-Boats] engine wierdness

took my boat out for the last of possible testing this season before
things get too cold and rainy. didn't go as i hoped. i'll
try and condense this down to it's simplest form:

BEFORE (about a month ago):

except for some slightly fast idling, engine ran well. Then I
noticed it starting to do this weird intermittent thing where all the
power (throttle) would just drop down to zero. It seemed to happen
mainly during acceleration up to plane. This all was happening at
the end of the season, so I have pretty much had the boat sitting for
the past month waiting for parts and time. But I was thinking it was
related to my falling apart carb and / or and electrical thing
related to my rebuilt shifter switch. so......

AFTER (yesterday):

- I installed my nice practically new carb (rebuilt by flying fish).
keep in mind, it was the exact same carb i have always had on the
boat, just completely rebuilt. I also changed my air water separator
cartridge beforehand to avoid any chance of issues from fuel that had
sat for a month.

- I installed a NOS shifter switch that I recently acquired. Tested
with light after install, everything checked out. And as I said,
it's basically new.

So after those two major upgrades, the engine is doing the same dang
thing. Started up, let it warm up a bit, took it for a spin.
About 5-10 seconds after getting up on that first plane everything
just dropped down to zero and unlike the past times, this time the
engine died at the same time. Had to crank it over several times
for it to start back up, and when it did, with the red lever set at
full throttle it took several seconds for the RPMS to climb up to
where they should be. I limped back to the dock.

Then while at the dock idling for a few minutes, all of the sudden
it just died again. At idle this time, not while accelerating.
And every time it dies it is quick. It's not like it sits there and
slowly dies. It just cuts out suddenly. So I of course tried to
restart it. Nothing for several tries, then it acted like it was
going to start, then it finally starts, coughing and sputtering a
bit, then very slowly climbs up to full throttle (in neutral).
I started thinking maybe a fuel pump issue. Disconnected fuel
line, cranked engine, plenty of pumping of fuel happening.

It seems sort of electrical in the way it just all of the sudden dies
either at idle or accelerating. Yet when it finally starts back up it
coughs and sputters and smokes a bit. Which sounds like bad fuel,
yet I have a new water/fuel separator cartridge, the carb is new,
and nothing looks dirty with the inline regular fuel filter.

Any ideas?
Received on Thursday, 29 October 2009