rotax 912 uls age2002

Check the gaps of the Triggers

2002 from memory does not have adjustments but you still need to check 0.3

check trigger resistance with calibrated multimeter

ERNEST BITTEN wrote:

My 2007 912ULS high wing had the same problem twice. Each early spring. I fly in the Pacific Northwest and use 91 Octane no ETH car gas. I replaced fuel lines, throttle springs, fuel filters, and cleaned carbs. Nothing worked until I dumped the fuel and put in 100LL. I suspect it was winter blend car fuel causing some sort of vapor lock when the weather started to get warmer. Now I fly with a 50/50 blend of car gas and 100LL. No more problems for years,

Ernest,

The fact that this happened with non-ethanol gas caught my attention. I’m in CA and that fuel is hard to get here except from specialty dealers that sell it for non-automotive use. A few years back I tried it for a couple weeks and immediately had a vapor problem. It was a warm spring day, similar to your experience, and the problem occurred at about 4500’.  I later tested the fuel and it had a very high RVP, about 13 PSI.  And because it was sold as a specialty fuel for off road use, I believe the RVP remained high right through the summer months.

I don’t know how non-ethanol fuel is regulated in other states, but my experience prompted me to learn about fuel vapor pressure and take it seriously.  I now use Chevron UL91 summer fuel, and when only winter fuel is available I mix it 50/50 with 100LL. We are starting to see more Swift UL94 outlets in our area, but not yet at my airport. The Swift UL94 has a consistently low RVP similar to 100LL.