AV Gas or Not

[oldfox]

Can you run 100LL in a 532 rotax engine and if so do you need to change the mix 50:1 of oil ? or will this just burn up the motor ?

[Mnflyer]

Hi oldfox, I burned a1/3 mix of Avgas (100LL) and 91 octane in my 582 for over 200 hrs didn't change anything engine ran good, removed it at 297 hr of engine change.

[carlisle]

100LL avgas is approved for use in Rotax 2 strokes including the 532. It will eventually, over the course of 25 to 50 hours or so cause metallic lead to be deposited on the spark plugs and rings such that vigilance is required to keep them clean. This entails more frequent disassembly of the cylinders in order to be done right. Some people consider this a small price to pay for the consistency of Avgas as compared to the various additives that auto gas stations add and may or may not admit to (ethanol, mtbe, etc).

Not necessarily approved by Rotax is the addition of TCP (tricresyl phosphate) in small amounts to 100LL. This fairly toxic chemical which is actually a weak pesticide (an organophosphate) causes the lead to react in the mixture to form lead phosphate which is instead deposited as a fine whitish powder, most of which is then purged via the exhaust. The remaining lead phosphate is much less likely to foul spark plugs or get into the ring grooves and cause sticking. TCP is available from Aircraft Spruce Co.

Chris Carlisle
Model 2, 582, C box (running 100LL and TCP)
Sioux Falls, SD

[Av8r3400]

Per a seminar I attended this past weekend, the speaker from LEAF - their shop manager - said that Rotax does NOT approve of the use of TCP in their engines. Decalin is the only additive approved by Rotax for dispersing lead in aviation fuel.

The speaker also noted that 100LL is an absolutely awesome fuel for 2-stroke motors (EGTs will drop!). Buildup on pistons, rings and combustion chambers notwithstanding.

[akflyer]

Some engines like the 100 ll others do not. We learned this the hard way running it in 2 stroke snomachines. Most of the issues were due to the fuel mapping on EFI machines, but even some carbed machines needed some tweaking on the jets to get it to run right.

There is no reason to be scared of the 100 ll if your doing a CC flight and it is easier to get it at the airport, but for the most part, if you can get ethanol free pump gas your better off.

[oldfox]

Thanks for the help guys me and my buddy just pick up the plane and we plan on flying some CC and just want to make sure we can use AV gas and what type of oil are you guys using ???