I have a 912 UL fitted on my Rans S-12 Airaile. I live in the Philippines (tropics). When I start the engine from cold (after burping) with full choke and closed throttle, the engine fires and idles smoothly. Warm up takes 'forever' but engine runs real sweet throughout the whole rev range. So, that's the easy part.
After returning from a flight and shutting down, I cannot get the engine to restart. The best I can manage is for the engine to fire and run so roughly that it is shaking engine and airframe apart. If I advance the throttle, the engine will not increase rpm and either stalls or continues to rattle. If I persevere (which I am loath to do because of the damage the vibration must surely be causing) the engine will, after about 45-90 seconds, suddenly spring to life and run smoothly. I have tried choke; no choke, throttle; no throttle - it makes no difference.
When the engine has been rattling itself to death, I have run a mag check; this doesn't affect the engine rough running in any manner but neither does the engine stop (ruling out an ignition problem!)
I've had the carbs stripped, cleaned and tuned; still no improvement! Battery is good; proved by the engine starting okay from cold!
I'm not an engine mechanic but my A&P guy (who has received some Rotax training) is also at a loss. We don't want to spend on replacement carbs or any other parts until we can definitively determine the cause.
The problem now has me grounded so I am desperate for help.
Thanks in advance to anyone who might have some ideas! :(
After returning from a flight and shutting down, I cannot get the engine to restart. The best I can manage is for the engine to fire and run so roughly that it is shaking engine and airframe apart. If I advance the throttle, the engine will not increase rpm and either stalls or continues to rattle. If I persevere (which I am loath to do because of the damage the vibration must surely be causing) the engine will, after about 45-90 seconds, suddenly spring to life and run smoothly. I have tried choke; no choke, throttle; no throttle - it makes no difference.
When the engine has been rattling itself to death, I have run a mag check; this doesn't affect the engine rough running in any manner but neither does the engine stop (ruling out an ignition problem!)
I've had the carbs stripped, cleaned and tuned; still no improvement! Battery is good; proved by the engine starting okay from cold!
I'm not an engine mechanic but my A&P guy (who has received some Rotax training) is also at a loss. We don't want to spend on replacement carbs or any other parts until we can definitively determine the cause.
The problem now has me grounded so I am desperate for help.
Thanks in advance to anyone who might have some ideas! :(
