cactusman
Well Known Member
I have had a successful 1st engine run, and successful taxi tests and was down to a carb balance which I attempted today after watching the video and getting a briefing from a RV-12 owner with several hundred hours.
I did a mechanical sync prior to first start and then went to a full taxi, run-up and a AHRS mag setup on a compass rose. All went fine. Last start was friday. Today (monday) went to sync and 1st warmed up engine and noticed the engine would start at low RPMs and then magically jump to 2000 RPM and that was the lowest idle.
After several starts and shutdowns with the carb balancing (dial type from Lockwood) hooked up, I frequently gave up on the balance and went back to the idle - finally ended up backing the idle screws all the way out and went to a fresh mech sync. That worked for a start. I got 1650 RPM at idle - warm engine. Everything green.
OK - started to sync again - idle first. Then I noticed the engine would start at 1200 RPM for a few seconds and immediately jump to 2800 RPM. Whoa.
Throttle cable at idle. Friction set. Everything looks fine. Choke secure - not the problem.
Called Van's and they think it might be the soft start modules. Checked all the plugs and wires and I didn't see anything screaming at me.
I think I will start from scratch tomorrow - do another mech sync, unhook the pneu sync equipment and see if I can get the idle set again. If not, I guess I am calling Lockwood in the morning.
If anyone has any suggestions - please by all means....right now I have an idle of 2800.....no cable issues that I can tell - all original Rotax springs and original throttle cable.
Many thanks
I did a mechanical sync prior to first start and then went to a full taxi, run-up and a AHRS mag setup on a compass rose. All went fine. Last start was friday. Today (monday) went to sync and 1st warmed up engine and noticed the engine would start at low RPMs and then magically jump to 2000 RPM and that was the lowest idle.
After several starts and shutdowns with the carb balancing (dial type from Lockwood) hooked up, I frequently gave up on the balance and went back to the idle - finally ended up backing the idle screws all the way out and went to a fresh mech sync. That worked for a start. I got 1650 RPM at idle - warm engine. Everything green.
OK - started to sync again - idle first. Then I noticed the engine would start at 1200 RPM for a few seconds and immediately jump to 2800 RPM. Whoa.
Throttle cable at idle. Friction set. Everything looks fine. Choke secure - not the problem.
Called Van's and they think it might be the soft start modules. Checked all the plugs and wires and I didn't see anything screaming at me.
I think I will start from scratch tomorrow - do another mech sync, unhook the pneu sync equipment and see if I can get the idle set again. If not, I guess I am calling Lockwood in the morning.
If anyone has any suggestions - please by all means....right now I have an idle of 2800.....no cable issues that I can tell - all original Rotax springs and original throttle cable.
Many thanks