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Need some advice
So, my workplace has just recently... (well maybe not that recently, it has already been over a year now) been operating twin engine Rotax 912S3s in the Tecnam P2006Ts since 2023 and it has been a challenge between the G1000 and the engines which has been frustrating as I really enjoy working on these units.
One of the more frustrating statistics has been that we have gone through two engines within about 300 hours and the airframe has less than 450 hours on it. Detonation that I thought was caused by fuel as we have a mandatory ethanol requirement in our Mogas but after a fuel sample was tested it passed with a RON98 designation antiknock index of 92.1 etc. So, I feel like I can mostly rule out the fuel, not to mention our other airframe is closer to 900 hours on the stock engines running the same thing. Based on what I was told by some of the guys at Rotech it is likely because the engines are being loaded too heavily and in a bad RPM range (2060 prop RPM at 22 InHg cruising at around 90 kts according to a pilot report)
Another frustration has been one engine has already had bad ignition units, but it was on our more reliable airframe, and it would seem I might be back in that boat with a hard starting engine that has about 344 hours give or take a few on the one that has now had two engine replacements. Currently I am dealing with an engine that refuses to start and has a tendency to kick back during a start attempt, a pilot with a ton of hours feels that it wasn't getting fuel because the fuel PSI was reading 0.4 but I also happen to know that when the fuel qty. on the G1000 doesn't show accurate, then neither will the fuel PSI so a quick reset of the EIS 2 fixed that issue and I am back up between 4.4 and 5.2 fuel PSI, not to mention I did check the carburetor bowls and they definitely had fuel in the quantity that I had expected to see
My inquiry is I am basically looking for advice:
-Aside from that recent service bulletin that discussed detonation and ways to avoid it, what are some tips and tricks that you guys might have had success with?
One of our unique problems is up here in Canada we will occasionally challenge the lower temperature range of the XPS 5W50 oil which I don't believe helps us out though we normally cancel flights below -30 Celsius but will fly above 30 Celsius in summer
-If one ignition module is no bueno would it be a bad idea to try to start it on a single module to try to isolate the issue?
-I tested the connector for the easy start with the starter disconnected and found only 10.5 volts on either pin when the starter button was pushed, is this too low of voltage? Resistance between the pins and the starter cable is about 4 ohms.
-I tested all the plugs on the engine with the ignition modules removed as per 912 MMH 74-20-00 page 7 and all the values look good according to the chart. I know there's only bench testing at a few locations like Lockwood.
I took my iRMT course a year and a bit ago at Lockwood, and I felt pretty well trained for this, but I am the only one working on these engines and it's tough to not consider that I may be the problem despite my best efforts. Ideally it would be nice to have another technician with training and experience to defer to them and discuss testing and diagnosis on these components
