Start Ignition

On the RV10 I've got the standard Vans IO-540, took out the right mag and used Lightspeed Plasma3 direct crank mini sensor as the replacement. Retained the left Slick RETARD MAG (NOT IMPULSE) but did not fit a SlickStart. Two indipendant switches are used to activate both systems. Now just doing first annual, both systems are timed to specs, the Retard mag (NOT IMPULSE) was only slightly off the recommended 25btdc so all good. My questions that I hope someone can answer are, can the timing of the TDC start retard points be checked or are they tied to the "main" running points ? Also do the retard points operate for starting at all when no external SlickStart is connected ? If the answer is no, have I been extremely lucky not to have destroyed the starter with a kickback because I've been starting with both ignitions ON with no issues for the first hundred odd hours ? Cheers from Western Australia

Retard points do nothing without a slick start.

Jesse said:

Retard points do nothing without a slick start.

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You don't need a Slick Start if you have the original type "vibrator" to generate the retarded spark. If you have been flying the airplane and it starts good, you must already have a vibrator for the left mag retard points. You can even hear it buzzing while the engine is cranking. The right mag should always be off for starting, either through the key switch wiring or left off if it is a toggle switch.

Thanks Jesse, so if the retard points do nothing without a SlickStart connected, is the magneto disabled as far as producing a spark at cranking speed? No RVSER no vibrator fitted and cause the right ignition is Lightspeed and not a mag its on all the time including start. The LightSpeed is TDC for start. My concern and question is...... if the LEFT RETARD MAG is not working for start, and I continue to start with both ignitions on, will my luck eventually run out with a bad kickback from the left 25 btdc Retard Mag ?

It sounds as if the Lightspeed is doing the starting and the left mag isn't actually firing at cranking RPM. I would activate the retard points in the left mag by wiring in a SlickStart (which also helps with hot starting) or a vibrator. I would then leave the Lightspeed off for starting. Or...

You could leave the left mag off for starting and continue to depend on the Lightspeed to retard it's spark during cranking.

GregMac said:

if the LEFT RETARD MAG is not working for start, and I continue to start with both ignitions on, will my luck eventually run out with a bad kickback from the left 25 btdc Retard Mag ?

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In its original (or at least intended) installation configuation, your retard magneto was wired to a set of contacts in the ignition switch that connected the retard breaker and the advanced timing breaker together during starting. This was essential to prevent kickback. It prevents the 25btdc points (in your left retard magneto) from firing during starting.

You may or may not have your retard breaker connected to a switch like it was in its original (or intended) installation.

If you don't have the retard breaker wired up as it was intended to be, then perhaps you have been lucky that you didn't get kickback. Mags don't typically generate spark at starting RPM of 10 to 20 rpm, but we can still get kickback.

If you just want to fly and not worry about it, then I would always start on the EI only... never with the magneto (unless you KNOW that it is wired as was intended). Your retard mag isn't helping with starting without the slick start or shower of sparks... so why take the chance?

The Lightspeed is known for making starting much easier than magnetos... so there is no reason to add a slick start... you already have the best starting system.