I have been using 100LL in the UL Power 350IS  and have had a leaky valve and only have 60 hrs on the motor.   Started mixing 1/3 100LL to 2/3  premium unleaded 91 octane Auto gas , in hopes that excess lead has built up on the valve and the new mix will clean the valve off.

   Is anyone burning straight 91 octane auto gas or any other  types of auto gas?   

 I have looked all over and cannot find any higher octane gas other then 100LL avgas and 105 octane race gas which is priced at 12$/gallon.

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' I'm using 92 (no ethanol) in my 260i, 175 hrs and no problems, although I did have to make a trip to eastern oregon, hot and high, to finally get my rings seated.  If I'm forced to use 100LL, usually while traveling, I add 2 1/2 0z. per 10 gallons of TCP additive.  That supposedly keeps the lead in solution and it burns thru instead of depositing.

Good luck,,,,,,,,,  Lynn   ch-701    UL-260i

Lynn, thanks for the information, pumping 100LL out of a electric pump, is much easier than using 5 gal cans of race fuel...... 

Do you know if there are different strengths or makers of TCP, the TCP/Alcor  I  f found , is to be mixed at 1oz of TCP/10gals of 100LL which is fine with me , as its costs around $14.00/OZ?

Hi Pete,  The product I use is "Decalin Runup"   fuel additive from "Aircraft Spruce".  16 Oz for about 23 bucks..   1/2 Oz. per 10 gallons..  I also built a little pump & filter unit for my DC 12V outlet.  Works great for those 5 gal. jugs  and fits into a battery box to take with me,    Maybe 2 lbs. max.

Cheers,,,,,,,,,,,,  Lynn  

I also use Decalin Runup and I've had very good results so far.  It makes a significant difference in the amount and quality of the lead deposits.  What little deposits build up are soft and flaky versus the typical concrete-like lead deposits.


Hi Pete, I'm using 93 octane auto fuel with 10% ethanol.   Only have 11.5 on the engine, but I'm going to try to avoid using 100LL if I can.  I bunker a small fuel trailer with fresh fuel in the hangar for all my planned local flying.  Not sure what I am going to do with planned cross country flights.  Good luck, and let us know how it goes with it and your engine oil cooling issue as well.  Dave

Pete any anyone else using the ULPower engine...here is  a good link for coming to learn about the UL engine.


Wow that’s not good. I am running a Rotax so this is an issue for me also. We went to the Canadian Rotax distributor (Rotech Research) and took an operation and maintenance course. One of the things we learned was how to clean the gear box at 1000 hours because when using 100LL it builds up with lead gunk deposits is important (and mandatory) to clean out. We also saw an engine that went to 2000 TBO that used 100LL exclusively. It was a mess but it did make it. You couldn’t even see the rings which were welded to the pistons. The heads and valves did not look good either. We also saw a 100LL 2000 hour engine that had used Decalin and it looked much much better. I came away with the conclusion that I will avoid 100LL whenever possible but will use Decalin when inevitably I have to use 100LL. I decided to install 4 fuel tanks so I could run mogas on longer trips. In fact, I just went to the Zenith Fly-In from here in Lethbridge. Alberta and was able to use only mogas. Peter, I flew right over Alexander on my way to Mobridge, South Dakota where they have mogas. Mexico, MO also has mogas and because of my 50 gallon capacity those were the only places I bought fuel. I hope the unleaded av fuel becomes a reality (contrary to everyone else who is running a Lycosaurus...)




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