915 Eurofox Bad First Start of the Day
in 915iS Technical Questions
2 hours ago
We are having issues with the first start of the day, especially in cold weather - see this video https://deesidegc.fyi/AP_start When this happens, the engine will not pick up with application of throttle and must be shut down & re-started, which it normally then does without issue.
We set the throttle using the Rotax throttle position vs temperature chart using the Kanardia EMSIS Engine Management display of throttle position. During investigations I noticed that there is a big discrepancy between the reported EMSIS throttle position (which matches BUDS) and the throttle travel movement measured with a ruler. For example, with the throttle fully closed, EMSIS/BUDS says its 0.32 (32%). As the throttle is opened the EMSIS eventually reports the position as 1.0 (100%), whilst there is still 16.7mm of throttle travel to go. At 50% throttle movement measured by ruler, the EMSIS says it's at 97% ! Thus using the EMSIS to set the initial throttle position means it's much less than if estimated using the throttle lever position. We tried reverting to estimated throttle position for the first start, but it's still bad.
Another 915 Eurofox has a similar throttle position discrepancy and occasional similar bad starting, so this is maybe "normal" but still doesn't seem right ! The throttle position can be calibrated on a 914 using BUDS/ TLR software but there seems to be nothing similar for the 915.
The throttle position discrepancy may be a red herring as far as our starting problem is concerned, but I would like to resolve both !
Any ideas ?
Mark
Sorry: Meant to add this to the other thread on the same subject, but can't delete this one now :-(
