Van's Air Force
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Fuel smell
- Thread starter svanarts
- Start date
Marc DeGirolamo
Well Known Member
fuel smell
Scott,
Perhaps the smell is coming from your primer pump (assuming you have one in the cockpit).......try changing the o-rings in the threaded cap and see if this helps.... just a thought
Scott,
Perhaps the smell is coming from your primer pump (assuming you have one in the cockpit).......try changing the o-rings in the threaded cap and see if this helps.... just a thought
Fuel Smell
After I bought an RV-6A I noticed a fuel smell in the cockpit, more pronounced when banking. After much work I located the source. The rudder cables had partially sawed into the vent lines. Found the problem after removal of the fuel tanks and with a friend inside the cockpit I applied air pressure to the fuel vent line at the wing root and covered the vent opening on the bottom of the airplane with my finger. My friend located the air coming into the cockpit via the partially cut vent line behind a bulkhead and the rudder cable. It was really hard to see. Put a splice into both vent lines and secured them away from the rudder cables so it wouldn't happen again.
Best regards,
Russ Daves
N710RV (RV-10 Reserved - QB Fuselage Stage)
After I bought an RV-6A I noticed a fuel smell in the cockpit, more pronounced when banking. After much work I located the source. The rudder cables had partially sawed into the vent lines. Found the problem after removal of the fuel tanks and with a friend inside the cockpit I applied air pressure to the fuel vent line at the wing root and covered the vent opening on the bottom of the airplane with my finger. My friend located the air coming into the cockpit via the partially cut vent line behind a bulkhead and the rudder cable. It was really hard to see. Put a splice into both vent lines and secured them away from the rudder cables so it wouldn't happen again.
Best regards,
Russ Daves
N710RV (RV-10 Reserved - QB Fuselage Stage)
Barry
Well Known Member
Fuel Leak
I had a similar problem which I occured when I moved the fuel selector (Vans supplied fuel selector) in flight to change tanks. The leak was very small and came from the spindle of the fuel selector. It only happened in flight when the tanks were pressurized with the air flow into the vent lines. I unscrewed the top of the fuel selector (this can be done when only a few gallons of fuel are in the tanks, the tanks do not need to be completely drained). There is a sort of O ring that seals the spindle to stop fuel leaking. I put some Fuel Lube on this O ring and that fixed the problem. If you disassemble the fuel selector take care that you put it back together correctly as there is a sort of keying device which can be rotated out of position.
I had a similar problem which I occured when I moved the fuel selector (Vans supplied fuel selector) in flight to change tanks. The leak was very small and came from the spindle of the fuel selector. It only happened in flight when the tanks were pressurized with the air flow into the vent lines. I unscrewed the top of the fuel selector (this can be done when only a few gallons of fuel are in the tanks, the tanks do not need to be completely drained). There is a sort of O ring that seals the spindle to stop fuel leaking. I put some Fuel Lube on this O ring and that fixed the problem. If you disassemble the fuel selector take care that you put it back together correctly as there is a sort of keying device which can be rotated out of position.
My CFI (the first guy who taught me to fly) still kind of hangs around and keeps an eye on me. His thought was that perhaps it was the fuel selector. So I'll take a look at that as suggested by both he and Barry pointed out.
But I have noticed the fuel smell more when banking as Russ points. And almost never when the tanks are less than half full. I'll definately take a look at the vent lines.
Great places to start! Thanks guys! I'll let y'all know what I find.
But I have noticed the fuel smell more when banking as Russ points. And almost never when the tanks are less than half full. I'll definately take a look at the vent lines.
Great places to start! Thanks guys! I'll let y'all know what I find.
Tom Martin
Well Known Member
The fuel smell will come from the spindle of the fuel selector valve. For me it happens about ten minutes into a flight when I have full tanks and the sun is out. The tank that is not selected gets pressurized by heating and the ram pressure at the vent which causes a bit of gas to leak around the spindle of the valve. To stop this I fly for five minutes on one tank and then switch to the other side. This works to stop the smell and usually I am at my cruising altitude by that time. You can test for leaks using a kleenex, it will show the blue colour of the fuel.
Fuel Smell
Scott,
One other thing to check...Check for fuel stains under the wings, just forward of the flaps. If you notice anything there, fill the tanks and check for drips. RV tanks are somewhat notorious for developing leaks simply due to the fact that there are no bladders and the wings flex a little with time, cracking the Proseal. You can also check the inspection covers on top of the wings. If there's fuel in there when full, you have a leak.
I had a minor leak there. I could also smell fuel in the cockpit when the tanks were full. Although I didn't build mine, guys who don't have a lot of confidence in their Proseal job (it's messy and toxic, as I'm sure many in this group will attest to) don't fill the tanks after flight...
Hope this helps.
Mike
RV-4 C-GJIP
Scott,
One other thing to check...Check for fuel stains under the wings, just forward of the flaps. If you notice anything there, fill the tanks and check for drips. RV tanks are somewhat notorious for developing leaks simply due to the fact that there are no bladders and the wings flex a little with time, cracking the Proseal. You can also check the inspection covers on top of the wings. If there's fuel in there when full, you have a leak.
I had a minor leak there. I could also smell fuel in the cockpit when the tanks were full. Although I didn't build mine, guys who don't have a lot of confidence in their Proseal job (it's messy and toxic, as I'm sure many in this group will attest to) don't fill the tanks after flight...
Hope this helps.
Mike
RV-4 C-GJIP
fuel smell
I have fuel smell in my -4 when I top off, actually even when 3/4" below filler neck. It shows up when I level off after takeoff. The outlets (intakes?) from the fuel vents are under the cockpit, and my "air conditioning" naca scoops are under the wings. After a short time the tanks are no longer sloshing the fuel into the vent tube at the top of the tank, and smell goes away. Topoff is the only time this happens, and there are no leaks at the caps. Also no leaks in the cockpit.
The ability to smell fuel venting is rather remarkable. In a 6A that I fly, with bladder buster tanks (bad idea), we had a small leak in a cap at the wingtip, and we could smell fuel in the cockpit. We landed immediately and found no leaks other than the wingtip cap. Blue streak down the wingtip. Hard to imagine that the smell could travel back into the cockpit from the wingtip, but it did.
Jeff
RV4 Toucan
I have fuel smell in my -4 when I top off, actually even when 3/4" below filler neck. It shows up when I level off after takeoff. The outlets (intakes?) from the fuel vents are under the cockpit, and my "air conditioning" naca scoops are under the wings. After a short time the tanks are no longer sloshing the fuel into the vent tube at the top of the tank, and smell goes away. Topoff is the only time this happens, and there are no leaks at the caps. Also no leaks in the cockpit.
The ability to smell fuel venting is rather remarkable. In a 6A that I fly, with bladder buster tanks (bad idea), we had a small leak in a cap at the wingtip, and we could smell fuel in the cockpit. We landed immediately and found no leaks other than the wingtip cap. Blue streak down the wingtip. Hard to imagine that the smell could travel back into the cockpit from the wingtip, but it did.
Jeff
RV4 Toucan
