Model Forum / Radio Controlled / Air Models / April 2004

Sounds as if it's running on the fuel that you shoot into the exhaust
port and then dying because it's not drawing fuel through the venturi.
You can disassemble the tank and make sure that the pickup tube is
attached to the needle valve nipple and that the tube is pointing down
to the bottom of the tank.  Some engines that have been sitting around
for years have hard, cracked pickup tubes.  Also make sure that the tank
has a good seal.  If it's leaking fuel from the back that could mean
that all the fuel is gone by the time you get it to start, and then it
just quits.  

The general procedure for starting a cox reed valve engine is to prime
and start, prime and start, prime and start, until the fuel gets sucked
up the pickup tube and into the venturi and it will continue to run for
more than a second or two.  Once you learn this procedure you may find
yourself priming and starting for half an hour without even thinking
about it if there is a problem.  If everything is in order it should
take only 2 to 5 times on a Pee Wee.  I can usually get my Black Widow
and Texaco to run after only 2 starts at the beginning of the day.

One thing that I like to do when I'm having trouble is to pressurize the
tank to prime the pickup tube and venturi.  After you fill the tank and
the fuel starts to come out the breather hole, cover the breather hole
and shoot a bit more fuel into the tank.  The fuel will be forced up the
pickup tube and into the venturi.  If you remove the needle valve and do
this, you can see the fuel ooze out of the needle valve hole.  Then when
the engine first fires up, it will be more likely to run because it's
already drawing fuel.

If you do all of this and still can't get it to continue running, then
you likely have a blockage in the fuel line or venturi.  You may also
want to check the reed valve to make sure that it isn't stuck in the
open position or in the closed position.  Either way will make it not
run.  If you suspect right now that your problem may be a result of your
engine sitting around and getting gummy and dirty for a few years, maybe
you should start by disassembling everything, washing it in a small
container of fresh fuel (use the cheap stuff or denatured alcohol from
the hardware store) and putting it together nice and clean.

Let us know what happens.