This was requested from a photo we posted some time back - it is a simple solution to the starter installation for the Rotax - but perhaps others have better ideas, ways of improving or can spot some problems with it.... for what it is, here it is....

Those who have Rotax horses under the hood will know that you only need the starter, well, to start.  Once fired up you can close that starter and set your warm up revs (we use 2500).

Technically the starter on the Rotax has no effect once you open the throttle - but could cause a rich cut once you reduce revs...

We copied (unashamedly and with his permission) the idea of Nigel Beale from Skydrive in the UK (probably the Guru of all Rotax things as the longest established dealer and inventor of some amazing things) an idea he has on his own machine - a light, automatically adjusting and totally unforgeable starter system.  

Basically it uses just one wire connected to both starters and looped onto the instrument panel.   It uses two cable adjusters on the firewall (20mm apart, exactly opposite where it simply pops through two #30 holes about 20mm apart  - use sleeves on the engine side from the carb to the cable adjusters (they only hold the sleeve and protect the wire), nothing needed between firewall and panel - honest...  we use bicycle brake cable, because you need something longer than supplied in the kit - but you can do away with the choke bracket...

When ready to start pop your finger through the loop and pull (make sure the right tension is set - ie about tighten off the cables at the carb end with a finger through the loop).  Once started, release and the starter will go back in and you cannot forget it - because you need your finger to do other things and without your finger it goes to starter off all on its own!!!

In the picture below we used a small piece of teflon tube - but it broke up and works better without - because the wire pops back flush with the panel now...



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Thanks for posting
Hi Jonathon

I am not sure what your are trying to achieve as the correct way to start a Rotax is to have no throltle and only use the Starter (chock) system to start you engine and as you push the starter in you then apply a little throttle to pick up the rpm to warm up revs if you are pushing the throttle in without pushing the starter in you are not following the correct way to start a cold rotax engine, once the engine is warm you do not use the starter system at all.

Cheers

Allan
Thanks Allan, you are quite right....

Clearly the throttle should be back to start - or it wont, unless already warm - then it will lurch into life. If you look carefully a the carb you will see the way that it works with the little hole near the big butterfly creating a direct sucking via the 'choked' carb. Of course, both carbs should be choked the same amount too... The aim of this starter system is

1) simplification of installation and no need to adjust - it is self adjusting by default cable can stretch and it will not need adjustment.
2) you cannot forget the choke/starter and leave it on risking a rich cut at low revs on approach.
3) it reduces the risk of sticking choke/starter cables
4) lighter installation (no choke/starter bracket, choke/starter knob, etc)
5) can be repaired/replaced anywhere you can purchase a bicycle brake cable...

We have used lots of different systems on many different Rotax installations, and this is the most reliable in our environment. Hope that clarifies...
Hi Jonaathan

Yes you make a few good points but in the 12 years I have flown rotax powered planes I have never had any of the problems you trying to stop from happening. Still it is a good discussion but I am a firm believer in not fixing what is not broken. but your system would be cheaper and simpler to build

Cheers
Allan
Cheers Allan,

It is worth noting that we are operating in a very very harsh environment, mission critical, over hostile terrain, far from support... it changes the approach and the mentality - simpler = better = more reliable = more safe = more smiles...

Fly safe

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