I have a 1982 skyline that while flying at 6500’ far in New Jersey, I noticed in the right fuel vent misty fuel coming out. I landed and found out I was losing close to 4 1/2 gallons per hour over my normal fuel burn…. My fuel flow gauge was showing normal that I was using 11 1/2 gallons per hour. When I did the math I was using 15 1/2 gallons per hour.. I was nervous about what I was seeing, so I made a fuel stop and found that I only had 8 gallons left in the tank and another hour and a half to fly which usually I’ll make a full tank with fuel left over… I had a shop in Florida look at it and they said they cleared a clog in the right wing vent tube… something‘s going on does anybody else have that problem?
You should have a copy of the airplane's POH in that airplane. It's a 182R. If you look at section 7 you will find this:
Both fuel vents have check valves on them, inside the tank. They are designed with a tiny hole in the poppet so that air can enter the tank quickly, but only exit slowly. This is to prevent losing much fuel. If the stem of that vent is not rotated to the upward position in the tank, the check valve is immersed in fuel for a longer period. If the poppet's hinges is gunked up or corroded, it will not swing shut and you can lose vast amounts of fuel. This is an inspection item outlined in the inspection check sheets in Chapter 2 of the Service manual, with details in Chapter 12, all of which most mechanics ignore altogether.
Mistake there, above: That vent valve is used in BOTH tanks in the 182R. Go back to the first diagram from the POH.
Now, if the fuel vent's inlet is not positioned correctly behind the strut as per the Service Manual, the tank gets incorrect pressures and suction could be pulling fuel out of the tank. If the vented fuel cap has a blocked vent, the suction could cause the bladder to collapse, with the bottom pulling upward and forcing more fuel out the vent. As the fuel exits and the bladder pulls up more, the fuel sender's float is also raised, giving falsely high fuel gauge indications. This can also happen if the fuel cap's gasket is shot.
Front and side views of the vent location. It's pretty fussy. This location is intended to minimize icing of the tube, but it also affects tank pressures.
The crossover vent tubes in this arrangement are long and are suspended from the roof of the bladder by small straps. They extend all the way across the tank to the outboard end, where there is some airspace even when the tanks are full. If those straps fail, the tube falls into the fuel and can easily transfer large amounts across to the other tank. This applies only to the long-range tanks.
Item 15 is the long crossover vent tube. "B" is the vent fed by the underwing vent, with the check valve on its inside end:
Time to get the mechanics to open that service manual and inspect the whole system properly.
