Fuel smell whilst flying

[Gagarin737]

At my RV-12 I had a small leakage at the "red cube", I initially used the wrong sealant (corrected it with Loctite 567). Afterwards I smelled fuel during take-off but it turned out to be the fuel tester tube lying in the wind stream of the "airconditioning".

[AaronG]

Fuel vapors in the cockpit are not normal, and indicate a leak. I would trace the entire fuel system from tank to carb, looking for blue stains or wetting, especially at the joints. You can also try this with the fuel pump on to pressurize the system. If you have pipe threads anywhere, make sure you used sealant, or you will get slow leaks at some. Flared fittings are also known for slow leaks, so inspect those carefully for and blue dye.

Aaron

[Hansgiant]

Thanks for all the advice. I guess I have my work cut out for me this weekend.

The most plausible suggestion is probably the connection between filler and tank as suggested here.
I will also check that there is perhaps not a float stuck in one of the carb bowls.

Many thanks again

I LOVE MY RV

[kalaharikid]

I also had a smell in my RV7 and it turned out to be a loose fitting on the loop of tank vent tubing inside the cockpit. Check those vent fittings for tightness.

[Hansgiant]

Ok so I took off the engine cowl and checked both carbs for leaks- with the engine running. No visible leaks detected on the engine side. I did find the jubilee clamps on the fuel filler tube in the cabin to be a bit loose- so tightened them up.

I like the suggestion that perhaps the fuel tester, which I keep in the right hand pocket near the 'air conditioning' duct may be the culprit.
Thanks for that.

Cheers

Hans the Giant

[RFSchaller]

I rinse out my fuel tester with isopropyl alcohol after each use. It gets rid of the auto gas smell.

[Hansgiant]

Ok, I recently spent around 4.1 hours in the RV12.
I only smelt the fuel when pulling back on the throttle on decent when approaching the airfield to land or on decreasing speed in turbulence.

Any ideas? Perhaps the return to tank feed is leaking as the fuel demand is not as high?

Any suggestions would be helpful.

Hans Giant

[RFSchaller]

If you are using 100LL you should see a blue stain if there is a leak. Auto gas of course would leave little if any evidence of a leak.

[AZLeeJay]

Hans,
Just to let you know I'm following this thread closely as I'm experiencing the same issues.
There is no evidence of fuel leaking inside the cowl or cabin so I guess its the gascolator next?

[JBPILOT]

When pulling back on throttle, the engine can get into a fairly serious vibration, which I'd say causes the carbs to leak a bit during that time. You'd have to be really fast to take the cowl off and actually see residual fuel on the carb shields. High heat would evaporate it so quickly, you won't see it.