I seen in the Tower magazine a three way valve for fueling. You just turn it one way to fuel, the other to the engine. Does this help?
Hope this doesn't constitue advertising, but here is the valve I'm talking about I seen on tower hobbies.
NOTES FROM OUR TECH DEPARTMENT
This Device is for Airplane Modelers that have their Engines
and Fuel Lines in "hard to get at" Places such as Cowlings.
FEATURES: One-Piece Valve Assembly installed into Airplane with
Convenient Fueling Probe for Refueling.
INCLUDES: One Pre-Assembled Fueling Valve (Glow Fuel)
One Fueling Probe (DUBP2339)
One Knurled Nut w/Serrated Washer
SPECS: Overall length (front to back): 13/16" (20mm)
Mounting nut diameter (what is seen on outside of cowl): 1/4"
Hole size (drilled through cowl): 3/8"
Length inside cowling: 1/2"
COMMENTS: Will require drilling 3/8" hole for acceptance of valve assembly.
NOTE: This will ONLY work with Glow Fuel.
For GAS Fueler, use DUBQ0655.