Intermittent starting ignition side

by John Wilfley in General Tech Discussion 6 years ago

I have a Rotax 912 US 930 hours and then having trouble starting this summer checked all fuel related issues, fuel side seems fine. ignition Side is our concern, can take the plugs out and ground them and it shows no spark whatsoever rotation seem strong, new battery change plugs checked gaps , ohm ed out magneto switches and checked every ground I could find , after several failed attempts, reinstalled new plugs in gap and it starts fine , did normal magneto checks everything’s within proper range only maybe 70 per side drop ,, each new first start of the day I have issues with firing , re-checked all the above with several of us and still can’t come up with an idea was wondering if it could be a bad starter or because of several attempts and week starts with the old battery could it be the sprag clutch , looking for things to troubleshoot ? again it’s definitely a spark related issue I believe any help would be most appreciated! Stingsport.

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Re: Intermittent starting ignition side

by Roger Lee » 6 years ago

Roger Lee

125 5.12k 4.53k

Try one thing first. Get a 1 gallon baggie and put some ice in it. On the first start of the day wrap this bag of ice (don't need a lot of ice in the bag, don't over fill it) and wrap it around the ignition modules. Let it sit and cool the ignition modules down for 30 minutes. Then try a start. If it starts right up replace the modules. Sounds like maybe the starting circuit may be going bad in one?????
If this fails we'll go onto another test. Make sure the plugs are gapped properly. Between .023 - .027. Do not pull the plugs and try and run the engine any more.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Re: Intermittent starting ignition side

by John Wilfley » 6 years ago

John Wilfley

8 23 29

I Will give it a try first thing tomorrow, on the first start I won’t try to start it before i cool the modules.
the problem if definitely intermittent, the modules are about a thousand for each......is there a way to test them or a place that can ( Lockwood) ?
Ps FYI what’s so puzzling is it won’t start and then I changed all the plugs Gap to .025 and it started great then it went back to not starting. then I cleaned both grounds on the intake manifold from the modules and again started great and then 30 minutes later it would not start again , each unsuccessful attempt I had to recharge the battery which took just a few minutes to get to 100% , another test we did today was trying to start it on one mag side only tried both sides it wouldn’t fire but it fired when both were on so yI’m thinking module as well , could you explain how the cold will help diagnose it ? It was actually only about 75° here today so was rather cool , I appreciate Rotax.com and the forum it is helped walk me through a lot of issues and also help me to learn the Rotax better ,thx Roger, I’ll let you know how it goes! Blessings J.

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Re: Intermittent starting ignition side

by John Wilfley » 6 years ago

John Wilfley

8 23 29

Hello Roger so I got to the airport and it hasn’t been started since it ran yesterday after cleaning those two grounds from the ignition modules to the intake I thought I would give it a try it started flawlessly so I’m not sure if I should try that cold test I don’t think it’s gonna make a difference I guess at this point I just ride it out and see how she works for a while, I read that the grounds for those could cause a problem it would be great to think that I found it and corrected it I hate to send those modules off to Carmol in the Netherlands for testing?or buy new ones at this point? Your thoughts are appreciated

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Re: Intermittent starting ignition side

by Roger Lee » 6 years ago

Roger Lee

125 5.12k 4.53k

You may just have one bad starting circuit in one module and it's starting on only one. What you don't want to do is just keep cranking it to death. You could eventually trash the starter and or sprag clutch. If this continues you need to address it and the sooner the better. If you have a hard time trying to start again try the ice.

p.s.
Are you getting prop kick back when trying to start?

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

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Re: Intermittent starting ignition side

by John Wilfley » 6 years ago

John Wilfley

8 23 29

Hey Roger thanks, In response, I don’t believe I have any kickback I’m not sure exactly what that is but I’m assuming it’s kind a like when you first turn it off it just stops abruptly but it’s never like not rotated in the proper direction when starting , i’ve seen a few of the videos with kick back and I don’t feel it’s doing that. , it May have done a little prior to getting the new battery I did crank in a bit to hard and lost power,but only once or twice.,
so I started this morning it was probably about 70° out which is cooler, I primed it for about 20/25 seconds applied choke hit the starter it popped / fired , released choke applied a little throttle and she started great! I let it run for a couple minutes and turn it off and started again in about 15 mins, it’s started fine ,went flying for about a hour ,let it sit about 30 mins, Engine temp was about 160 and it started immediately . I’m kind of hoping that maybe the two grounds on the intake from the modules cleaning that was the problem? So far so so good . I do know that I never had problems until just after last winter , in November last year I went from a hanger to a shade port and it gets pretty cold and windy in St. Louis and wondering if just the condensation and being outside could’ve had something to do with a few problems I’ve had , had to replace my wood comp prop that split at the hub which I believe was weather related and now this summer it has gradually been harder and harder start . Can you keep starting like today I would say we’re back to normal , if it’s not the ground I suspect the modules as well based on everything and have been gleaning on Rotax.com about different people having module failures , thanks again for your help ,I’ll keep you posted , If the problem arises again what’s your thought on sending the modules in for testing @ Carmo electronics ., and yes I won’t crank it to death ,J.

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Intermittent starting ignition side

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