REW, Yes, the fuel pump should have a restrictor fitting on the outlet side of the pump. That could be your problem, but if the plane has been sitting for a long period, there may be residue in the overflow line from the cowl tank.
The fuel system works like this:
The wing tanks are interconnected so that the plane stays in balance as
the
fuel is used from the tanks. ( no need or way to seperate the wing tanks)
,
Fuel is drawn from the right tank to the fuel pump, and is pumped at a
rate
exceeding the maximum useage rate of the engine - but not by very much.
This
rate is controlled by the outlet fitting on the fuel pump. At lower than
full
power settings, then there will be considerable excess fuel pumped to the
cowl
tank. Excess fuel is drained back to the left fuel tank by gravity,
through a
drain line that is located on the back side of the cowl tank. (Later
versions
had fuel inlet and drain lines mounted on the bottom of the cowl tank,
along
with the fitting feeding the carb.)
If the restrictor has been left out of the outlet port of the fuel pump,
too
much excess fuel will be pumped, exceeding the drain line from the cowl
tank,
and gasoilne will flow out the top of the tank.
THAT IS A GOOD WAY TO BURN & CRASH !!!!!! Raw gasoline draining
down into the
cockpit where electrics are sparking - or possibly sparking is not a good
safe
environment!
Recently I let my coupe set for quite a while. After restarting to use, I
had
the same problem you do.. gasoline flowiing out the cowl cap.... WoW.
I found the drain line partially stopped up at the elbow fitting on the
side
of the cowl tank. Difficult to get to, but I was able to remove, and clean
-=--lots of gunk - I don't know where it came from, but it was stopped up.
Cleaned it out - solved the problem...
Under the instrument panel, you can see the two lines on the back side of
the
tank--near the top rear side. One is the line from the fuel pump. The
other is
the drain line. Carefully remove the fittings and clean..... You may have
to
remove a radio or instrument in order to get to the fittings.....Not hard,
but
you are upside down....
Be sure to have a fire extinguisher available close by...
You can check out the drain line - somewhat, by slightly pressurizing the
cowl
tank - no more than 1 -2 psi --- preferably by blowing into the tank
filler
opening....... tastes bad, and gets your mouth dirty, but you can quickly
see
whether there is free passage through the drain line, and hear air
bubbling in
the wing tank... You can also pour gasoline into the cowl tank - it should
drain fairly quickly, but I CANNOT TELL YOU THE RATE......If the elbow is
partially stopped up ( as I suspect), the trash should be cleaned out, not
forced into the wing tank....to cause future problems.
This should be accomplished in about 1/2 hour or so...
If the drain line is clear, then we will review the restrictor.
fitting....
Somewhere I have the part number of the proper outlet fitting. It is
simply a
normal fitting, but is drilled with a very small hole....
Fix the problem before running the engine or flying again......We don't
need a
flame out!
Fly Safe - Have Fun
Regards,
Harry Francis
93530
Blacksburg, Va.
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