Fuel System Damage from Ethanol

Pilots using normal pump gas i.e. ~10% Ethanol check your fuel system components for signs of damage.

This can effect:

Plastic & Rubber fuel lines
Gaskets & Seals
Fuel Primers
Fuel injectors

& even Composite Fuel Tanks

I recently replaced the fuel lines & fuel primer bulb in my 4 cycle high end weed eater. It is a lesson in the long term damaging effects of Ethanol in a fuel system not rated for it.

I’ve seen transparent / yellow tint fuel lines used in aviation from powered parashoots to high performance home built aircraft. If your running 100 LL or marine gas 100% of the time you should be good. however if you occasional or full time run normal auto gas with Ethanol in it you should look for potential signs of damage in your fuel system.

The Yellow lines are more visually obvious when they fail, if you have a black rubber hose then check for signs of cracking, turning grey or brown and do the flex test looking for cracking.

if one of the lines splits like what is shown above at best case your engine will be starved of fuel and you will become a glider. at worst case a roman candle.

Hopefully this will save someone from having a bad day.


EAA Technical Counselor in Power plant / Fire wall forward & Composites

For more info on the EAA Technical Counselor
program visit:

EAA Technical Counselors