Vapor lock

[Arnieb]

The other day I was flying when my engine kept stumbling, so I decided it was my best interest to get it back on the ground. I no sooner landed when the engine quit but it started right back up. It seems to me that this could be caused by carburetor ice but talking to people at the EAA they told me that it sounds more like vapor lock. The engine is a Jabiru 3300 with an aerocarb with only 5.1 hours total time.

[kmacht]

Search the forum for the “Sonex burps”. It’s a common issue with the aerocarb. Dont continue flying until you have at least taken steps to minimize them.

Keith
#554

[Ed Perkins]

I agree, a very common problem in hot / humid weather where one is using the Aerocarb. Most of us have solved this with wrapping the fuel lines with a heat protecting material. Don't fly in hot weather unless you get this fixed first.

[Arnieb]

Thanks for the help, i wrapped the fuel line with heat reflecting tape and also wrapped the exhaust hopefully this will solve the problem.

[vigilant104]

Also, gasoline and especially gasoline with ethanol has a lower vapor pressure than 100LL, so is more likely to form vapor bubbles when heated or at lower pressure (i.e. higher density altitude).

[mike.smith]

Thanks for the help, i wrapped the fuel line with heat reflecting tape and also wrapped the exhaust hopefully this will solve the problem.

I have fire sleeve, plumbing pipe insulation, and heat reflecting fiberglass tape on the fuel lines. Never a burp.

[Onex107]

I don't mean to be picking nits, but, to be correct a high vapor pressure fuel is more likely to vaporize than low vapor pressure. It's the way vapor pressure of fuels is obtained. The standard test is a measured sample of the fuel is heated in a closed measuring system to a standard temperature and the pressure is measured. The easier the fuel is to vaporize the higher the pressure.
Auto gas, especially the winter mixture, has a higher vapor pressure than 100LL and is more likely to cause the burps at the same temperature.