Nigel,
I think the point has to be made that the engine must be turning over
before switching in a mag. It is to do with the ignition timing being
slightly too advanced until full starter speed has been attained,
particularly with the higher compression ratio. With any mags.switched in,
pre-ignition can cause kick-back.
For me, the answer would be to keep the key switch for starting, and fit a
couple of self returning single pole lever switches for the mags.
Speaking as an Engineer (which I rarely do these days), I would rule out the
use of relays unless there was simply no alternative.
Best regards. Bryan
----- Original Message -----
From: "nigel charles" <nigelcharles@tiscali.co.uk>
Subject: RE: Europa-List: 912S starting
<nigelcharles@tiscali.co.uk>
>
> I also found that starting using a single magneto minimises the risk of
> kickback. For those already using a key switch there are 3 ways of
> overcoming the problem:
>
> 1. Fit a starter push button in parallel with the existing key switch
> 2. Fit an extra switch to temporarily short out one magneto during
> start. This will mean that the switch will have to be switched off again
> after start.
> 3. Include a relay on the starter circuit which will short out a magneto
> during start. This has the advantage of no changes to the panel
> switches.
>
> The newer starter will only fit the XS. This is because it is longer and
> would interfere with the Classic engine mount.
>
> Although kickback can occur with all variants of the Rotax the 912S
> suffers the most due to the higher compression ratio.
>
> Regards
>
> Nigel Charles
>
>
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