Hey Glen: The problem is/was most likely in the fuel delivery system of the
Alon. The fuel strainer is on the firewall, and the line to the carburetor
SHOULD be up hill all the way to the carburetor, but may not be.
Secondly, Geoff did not put much fuel in the header tank. If there was any air
or
water in the line, which could have easily accumulated over the days of
being empty, this is difficult to remove. Thirdly, with the previous water in
the system, there could be a partial blockage of the fuel pump screen.
All of these together could have caused the 30 second runs. But each
30 second run provided more fuel into the header tank which increased the
fuel head pressure to the carburetor. As you increased the head pressure, you
eventually removed the air in the line and then the engine ran normally.
Fill the header tank and check the pump screen. If it runs Ok then, go
for a test flight insuring that you have a place to land if the engine
quits, but plan on keeping it running using the primer if necessary. There
should not be a problem, but there still might be some air in the line to the
carburetor from the fuel strainer. And this could cause the engine to
sputter or even quit when you raise the nose for climb out.
(Just ask Gene Gagliari)
Keep the nose attitude low in your first take off, and after climbing
up to at least 3000, raise the nose to the stall. If the engine wants to
quit, you know what to do. Once you have all the air out of the line to the
carburetor, there should not be a problem.
This is why Alon had 3 or 4 bulletins on changing the fuel system. (I
do not remember all the numbers, but I believe two of them are 16 and 19)
See you next week end.
Lynn
In a message dated 9/5/2010 10:31:41 P.M. Eastern Daylight Time,
[email protected] writes:
Gang
Can you help me diagnose why the engine keeps quitting after 30 seconds or
so? Please review the sequence of events and offer your thoughts:
Aircraft was found to have excessive water contamination due to sitting
outside with cracked fuel cap gaskets. All three tanks were drained
completely.
2. Because one of the main tanks had some weeping through the
rivets, we removed the tank and sloshed it with a Flame Master product. After
4
days of curing, the tank was reinstalled. About 2 quarts of fuel were put
into the header and 5 gallons into the mains.
4. Engine was started with one shot of prime but only ran for a few
seconds.
5. Engine was restarted several times but only ran for a maximum of
30-45 seconds before stopping. Various attempts were made to adjust the
mixture from within the cockpit and also to use the accelerator on the carb
(via the throttle) but the engine ran rough and eventually cut off within
30-45 seconds.
6. If the engine was allowed to sit turned off for 1 or 2 minutes,
it would restart and run for the 30-45 second interval.
7. Aircraft allowed to remain tied down over night.
8.
The next morning the engine started with one shot of prime. The engine
continued to run smoothly for over 5 minutes at various power settings.
That is, it appears that the engine is running OK.
Before taking the aircraft for a flight, I would like to have a better
idea as to what might have happened to cause this problem. Please note that
the aircraft was completely drained of fuel, including the carburetor, for
approximately 8-10 days.
Thanks
Glen
Glen Davis
917 297 1111
_www.ishootpictures.com_ (http://www.ishootpictures.com/)
