stc for mogas

[rick]

Would anyone want to jump in and explain what exactly is done to an airplane engine for the stc to use mogas. I have heard everything from nothing to hardning of the valve stems, and this is from different aircraft mechanics. One even said just use it. I find that hard to believe what with all the stc business.

Rick

[maules.com]

Rick, you'll see various comments re mogas throughout this site. The engines are not built to be STC'd for mogas, rather the engine and airframe installation are tested by EAA or Peterson to prove they can or cannot run on it, and then installation modifications are done.
For instance, the Maule O540B4B5 and O360C1F and C4F have cool ducts at the gascolater and engine fuel pump, plus the Dukes pump is replaced with 2 facet inline pumps plumbed paralel with one running continuously. This was done before the advent of alcohol and ethanol in the fuel which rots certain seals, gaskets, fuel line linings, etc.

[Lowflybye]

For instance, the Maule O540B4B5 and O360C1F and C4F have cool ducts at the gascolater and engine fuel pump, plus the Dukes pump is replaced with 2 facet inline pumps plumbed paralel with one running continuously. This was done before the advent of alcohol and ethanol in the fuel which rots certain seals, gaskets, fuel line linings, etc.

We just had ours put on the O-360 this last week and I got to fly 93 octane for the first time this weekend. I put 8.5 hours on her and loved the fuel bill (comparatively). I was surprised when we opened the box and found scat tubing and vent scoops along with the dual fuel pumps. I thought it would just be a new fuel pump and some paperwork. It was not that hard to install and seems to be well worth it. We have a Shell station less than a 1/4 mile from the airport so it is very convenient. There are about a dozen aircraft on the field running MoGas and we all get it from the Shell. So far nobody has found any alcohol / ethanol in the fuel, but we still check for it each time we fill a new tank.