Tuneturkey
Well-Known Member
Need some help troubleshooting and diagnosing why my engine stops dead.
Posted same subject some time ago of engine stopping on maiden flight/ solo flight in a High Max with the 503. Have gone through much back and forth as to things to check, things not to do, etc. Having determined that it had fresh pre-mix in the correct ratio; egt, cht were in reasonable proximity to acceptable levels, the engine had been warmed, engine had not been run in the lean zone, etc., etc., it failed again.
This time the plane was tied down, warmewd up and brought up to full power. RPM got to 6500. egts were 1100 an 890, OAT was high 60's. After 3 minutes, it shut down like it did in the air. Didn't sputter, cough or part run, it stopped just like the kill switches had been activated.
Pulled the bowls and both carbs had fuel. Fuel lines were all full, no bubbles. filters were new, no visable failures on the engine. crank turned freely.
Attempted a restart, and after lots of pulls, it started, idling roughly, and was not responsive to the throttle. giving it more throttle caused the rpm to go down. Tiny tack indicated 1600 rpm vs normal 2200. with air filter off, the carb slide (Bing54) was lifted on the front carb and response was same as experienced with the throttle. lifting the slide on the aft carb had no response at all, like the aft cylinder was not functioning. activated the kill switches on the mags one at a time and had no effect.
since then, the kill switch wiring was checked for grounding and continuity and nothing found.
General consequence is that the problem is in the DUCATI ignition system. Either a CDI pod, or bad connection in wiring. However the point of having dual CDI's or mags is to have a backup if one fails. In this case the engine stopped. Didn't run slower, or shudder, or cough. Consequently, my thinking is that something in the ignitiion system, common to both CDI pods, wiring, device, generator coils, in case which case engine woujld stop for lack of voltage of insufficient voltage.
Next step is to gain access to all components and take impedence reading to compare with the ROTAX charts.
The engine has a little over 8 hours running time. The prop is an ultra prop, three blade with 12 deg pitch blocks. Engine jetting is per ROTAX recommendations.
Comments from some of you experienced ROTAX users would be appreciated while I have the thing open for testing.
Posted same subject some time ago of engine stopping on maiden flight/ solo flight in a High Max with the 503. Have gone through much back and forth as to things to check, things not to do, etc. Having determined that it had fresh pre-mix in the correct ratio; egt, cht were in reasonable proximity to acceptable levels, the engine had been warmed, engine had not been run in the lean zone, etc., etc., it failed again.
This time the plane was tied down, warmewd up and brought up to full power. RPM got to 6500. egts were 1100 an 890, OAT was high 60's. After 3 minutes, it shut down like it did in the air. Didn't sputter, cough or part run, it stopped just like the kill switches had been activated.
Pulled the bowls and both carbs had fuel. Fuel lines were all full, no bubbles. filters were new, no visable failures on the engine. crank turned freely.
Attempted a restart, and after lots of pulls, it started, idling roughly, and was not responsive to the throttle. giving it more throttle caused the rpm to go down. Tiny tack indicated 1600 rpm vs normal 2200. with air filter off, the carb slide (Bing54) was lifted on the front carb and response was same as experienced with the throttle. lifting the slide on the aft carb had no response at all, like the aft cylinder was not functioning. activated the kill switches on the mags one at a time and had no effect.
since then, the kill switch wiring was checked for grounding and continuity and nothing found.
General consequence is that the problem is in the DUCATI ignition system. Either a CDI pod, or bad connection in wiring. However the point of having dual CDI's or mags is to have a backup if one fails. In this case the engine stopped. Didn't run slower, or shudder, or cough. Consequently, my thinking is that something in the ignitiion system, common to both CDI pods, wiring, device, generator coils, in case which case engine woujld stop for lack of voltage of insufficient voltage.
Next step is to gain access to all components and take impedence reading to compare with the ROTAX charts.
The engine has a little over 8 hours running time. The prop is an ultra prop, three blade with 12 deg pitch blocks. Engine jetting is per ROTAX recommendations.
Comments from some of you experienced ROTAX users would be appreciated while I have the thing open for testing.
