Rotax Ignition Modules Starting Procedure

H. Paul Shuch is a Light Sport Repairman with Maintenance ratings for airplanes, gliders, weight shift control, and powered parachutes, as well as an independent Rotax Maintenance Technician at the Heavy Maintenance level. He holds a PhD in Air Transportation Engineering from the University of California, and serves as Director of Maintenance for AvSport of Lock Haven.

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dstclair
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Rotax Ignition Modules Starting Procedure

Postby dstclair » Sat Apr 08, 2017 7:31 am

My old ignition modules failed several years ago and I replacement them with the 'new' ones which of the soft start feature. We did not wire in the soft start feature at the time. In my annual this year, I had the mechanic hook it up. He advised that I now need to start on the left module (instead of both) then switch the right on immediately after the start. Works fine. But I though the modules automatically handled the handled the soft start functionality (since both have the circuitry) so starting should be as before. Am I missing something?
dave

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FastEddieB
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Re: Rotax Ignition Modules Starting Procedure

Postby FastEddieB » Sat Apr 08, 2017 7:42 am

Pretty sure you are correct. They both have the soft start circuitry so no problem starting on both.

I needed to start on one ignition when I had my Bullyhawk soft start modules. Now with the factory soft start modules I start on both and it starts fine.
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3Dreaming
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Re: Rotax Ignition Modules Starting Procedure

Postby 3Dreaming » Sat Apr 08, 2017 11:52 am

If you have the Rotax modules, and both are hooked up for soft start, then you should be starting on both. some claim that because of the retarded timing that you need to start with a higher throttle position, but that has not been my experience.

roger lee
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Re: Rotax Ignition Modules Starting Procedure

Postby roger lee » Mon Apr 10, 2017 4:07 pm

Start on both. They are designed for that and both have the soft start as they are identical. They start on 3 degrees ATDC instead of the older 4 degrees BTDC. They hold that for about 5 seconds or so then swap over to 26 degrees BTDC. Don't just start using only one. On the older Bully Hawk they had to do that because they were only hooked up to one module. That is not the case here.
Throttle postion as far as the modules go have no interaction. If you have a low idle rpm then crack the throttle. If you have a high idle rpm then leave it closed. Use the choke first start of the day. When you use the choke use it all the way or not at all.
Roger Lee
Tucson, Az.
LSRM-A, Rotax Instructor & Rotax IRC
(520) 574-1080 (Home) Try Home First.
(520) 349-7056 (Cell)

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drdehave
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Re: Rotax Ignition Modules Starting Procedure

Postby drdehave » Mon Jul 03, 2017 1:03 pm

Roger said: "When you use the choke use it all the way or not at all."

Right now, I have a "bad" 1/3 carburetor choke that is sticking open, after use. My mechanic has tried servicing it twice, to no avail; it is still sticking, if I use full choke, but not with 1/2 (or less) choke.

So, is it a problem starting cold, with 1/2 choke--whilst I wait 4-6 weeks for this "back-ordered" part? (Which, by the way, is not cheap, at $353, complete.) Seems to start very nicely cold, with 1/2 choke...
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roger lee
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Re: Rotax Ignition Modules Starting Procedure

Postby roger lee » Wed Jul 05, 2017 8:17 am

Sticking choke should be easy to fix.
Take it off and push the shaft out of the housing and install a new "O" ring. Take a scotchbrite pad and polish the outside edges of the choke disk and do the same on the inside surface of the choke housing. Don't be af aid to polish up the choke disk edge good. Apply a tad of white lithium grease to the "O" ring and put the shaft back in the choke housing. It should operate smoothly now.
When I rebuild carbs I polish up all of them.

p.s.
You may want to have a choke gasket handy in case the old one gets damage when you pull the choke off the carb.
Roger Lee
Tucson, Az.
LSRM-A, Rotax Instructor & Rotax IRC
(520) 574-1080 (Home) Try Home First.
(520) 349-7056 (Cell)

3Dreaming
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Re: Rotax Ignition Modules Starting Procedure

Postby 3Dreaming » Wed Jul 05, 2017 8:28 am

I had one that after doing all the things Roger mentioned it still stuck. It moved fine until the nut was tightened down. I finally took a file and removed some material where the shaft exited the housing, and that freed it right up.


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