Fuel Contamination

"My engine fires up after several attempts but on occasion quickly and unexpectedly loses RPM until it stalls out. Everything is OK as long as I keep the throttle relatively high, low RPM's randomly cause a stall, after which the engine is difficult and sometimes impossible to restart."

SOUND FAMILIAR?

Here's what other had to say about similar problems:

Tony Astarte, #512

We had the same problem, it turned out to be contaminated fuel. We never drained the gas tank and we found that there was years of accumulated gunk at the bottom. If possible try to collect some fuel from the bottom of the tank or disconnect your fuel line and let some drain into a clear container. Also check you fuel pump.

Mike Lehmkuhl, Renegade #3, ATHENE

Sounds like a fuel problem:

1. Make sure your fuel vent is free and clear (you will hear a hissing sound if you uncap the

tank if the vent is clogged).

2. Make sure your carb is clean... A piece of dirt may be floating around clogging the jet

nozzle.

3. Make sure your fuel filter is clean.

4. Are you using the choke on start up?

Rob Squire, #95, Head Over Heels

Sounds like the idle jet is clogged.

Dana Berube, #99, JADE

May I make a suggestion, you should join "The atomic4-list" brought to you by SailNet:

http://www.sailnet.com/ this e-mail list also... You will find the A4 list to be a valuable resource.

I was plagued last summer by exactly the same symptoms that you have described... I tried everything on the ignition side, (well, almost everything) new coil, new distributor cap, wires, rotor, brain for electronic ignition, etc. Didn't fix it.

Late last season I focused on the fuel system... electric fuel pump, new fuel lines and filter, carburetor rebuild... finally seemed to improve things (a very tiny amount of dirt in the fuel line can cause all sorts of grief with the carburetor)...however, I didn't run the engine enough to be certain if I had found the culprit... the next thing to check is fuel tank vent (hose that runs from tank to stern of boat), if clogged - would cause exactly the problems we have experienced- fuel line lock or starvation.

The frustrating thing is- when the engine misbehaves it may not be due ONE big thing, but an accumulation of small things- that are all due to lack of maintenance by the previous owner.

Keep the faith. A4s are not rocket science...just needs some TLC and determination.

Mickey Feldman, #644

Sounds like the infamous crud/water in the fuel problem to me. There was considerable discussion on this a couple of months back as I recall - at least on several alternatives for cleaning out the fuel tank, and other components that are likely affected. You may find useful stuff in the archives (onelist does maintain archives, yes? no?).

Ray Alsup, #256, Pegasus

Excerpts from my log the day I purchased Pegasus and was moving her from San Francisco Bay to the California Delta:

1420 - Engine stalled. Sounded like it ran out of gas. I reached down and touched the starter and the engine restarted in a heartbeat.

1435 - Engine stalled again. My project started earlier than expected. I trimmed the sails so Pegasus would take care of herself and went below to look for the problem. Without an engine I would arrive much later than expected and have to sail a strange boat into a strange slip (something I was NOT looking forward to) or, spend the night on the hook (safer option).

1445 - Problem located. It was similar to a problem I had with by first car - a 1939 Pontiac purchased for $50 while in high school. Pegasus's built in fuel tank had 37 years of lacquer build-up that was flaking off and clogging the fuel filters (1 in-line and 1 spin-on). I rapped on the filters to jar the flakes loose and allow the fuel to flow. The engine started again and ran fine - as long as I did not over rev it and, I continued to rapped on the the filters every 5 min.