After normal mx, our 912uls (approx 700 hrs) is running extremely rough.  So rough that a carb sync is not possible.  Local AP IA is assisting, not a rotax guru, but is familiar with them.  He thinks a carb is not functioning.  


Here is a summary - Installed on a Vans RV-12


-Gearbox overhaul by Lockwood - all ok and re-installed on a/c

-Both carbs had the "5 year" overhaul by Lockwood

-New air filters

-New spark plugs, gapped properly (.28)

-Replaced a carb drip tray

-New engine mount isolators

-Throttle cables reinstalled on carbs per VANS Kit Assembly Instructions (never removed from carb mounting bracket)

-Did not change oil, so no need for oil purge

-Floats weighed within spec (each around 6g per set)

-Ignition check on last ground run was well within specs (prior to condition inspection)


Engine was running fine when last run (about a month ago before the condition inspection)


Pulled plugs and all look to have been firing


Engine starts OK - and "soft start" seems to be working, roughness from the start.  


Fuel is getting to both carbs equally


As rough as it was running, no fuel overflowed into the overflow tubes or drip trays


More troubleshooting to commence - 

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