I posted something last year in the electronic ignition forum but a lot has changed since then. I'll describe the problem.
RV-6, O-320, Slick Impulse Mag, Plasma 1 EI unit
1. Mid 2018 the engine became very hard to start. Once started it was fine. It sometimes even kicked back after the keyswitch was released from the start position.
2. With an LAA Inspector helping me we ascertained fuel to cylinders was OK and air to cylinders was OK. But there was still no sign of ignition when key was on START.
3. We ended up swapping the LEFT and RIGHT wires on the back of our ACS keyswitch. LEFT to terminal 1 with the jumper removed, RIGHT to terminal 2. Bingo, she now starts. So we were effectively now starting on both mags.
4. Flew many hours and all ok.
5. Magneto came off for 500hr inspection - impulse coupling wasn't engaging, various new parts and now she starts even better. I think, "great maybe that will have fixed the old starting problem!".
6. We always suspected the key switch could have developed a fault as well. When moving the key from RIGHT to LEFT on a mag check, the engine would stop firing for a fraction of a second. It does this regardless of how the switch is wired. See this video here. Turn the sound up loud to hear it best.
7. I fitted a new key switch and wired to the original terminals; RIGHT mag to terminal 1, LEFT mag to terminal 2 as per this diagram. I then take the aircraft outside and guess what, absolutely no signs of her starting. I then swap the wires back to how we did it in step 3 - she starts perfectly.
So - the Slick mag is now ok. Key switch must be ok (it can't be two units with the same problem built 20 years apart).
My electrical knowledge is minimal. What else between the key switch and the mags could be causing the problem?
RV-6, O-320, Slick Impulse Mag, Plasma 1 EI unit
1. Mid 2018 the engine became very hard to start. Once started it was fine. It sometimes even kicked back after the keyswitch was released from the start position.
2. With an LAA Inspector helping me we ascertained fuel to cylinders was OK and air to cylinders was OK. But there was still no sign of ignition when key was on START.
3. We ended up swapping the LEFT and RIGHT wires on the back of our ACS keyswitch. LEFT to terminal 1 with the jumper removed, RIGHT to terminal 2. Bingo, she now starts. So we were effectively now starting on both mags.
4. Flew many hours and all ok.
5. Magneto came off for 500hr inspection - impulse coupling wasn't engaging, various new parts and now she starts even better. I think, "great maybe that will have fixed the old starting problem!".
6. We always suspected the key switch could have developed a fault as well. When moving the key from RIGHT to LEFT on a mag check, the engine would stop firing for a fraction of a second. It does this regardless of how the switch is wired. See this video here. Turn the sound up loud to hear it best.
7. I fitted a new key switch and wired to the original terminals; RIGHT mag to terminal 1, LEFT mag to terminal 2 as per this diagram. I then take the aircraft outside and guess what, absolutely no signs of her starting. I then swap the wires back to how we did it in step 3 - she starts perfectly.
So - the Slick mag is now ok. Key switch must be ok (it can't be two units with the same problem built 20 years apart).
My electrical knowledge is minimal. What else between the key switch and the mags could be causing the problem?
