Ken Posted January 18, 2023 Report Share Posted January 18, 2023 Hi Folks: I flew for a few hours today. When I did my initial "mag" check before taking off everything was fine at 3500 RPM. When I bumped it to 4000RPM on "mag" 2 only the engine ran really rough. I checked for a loose ground and thought I found it and everything was fine. Then the issue came back again. Any thoughts on what might be the issue. I did not have time to switch out the "mag" wiring by switching the plugs around to see if the issue moves to "mag" 1. I will do that another day. Everything is still fine at 3500 rpm nice and smooth on on "mag" 1 and 2. Thanks for any ideas. Ken N296CT Quote Link to comment Share on other sites More sharing options...
Anticept Posted January 19, 2023 Report Share Posted January 19, 2023 Check boots and plugs resistances, and that the boots are clean and don't have a ton of sooty buildup inside of them. A bad plug is the easiest thing to fix, boots second. I will place 5 bucks on it that those are your issues. The boots and plugs each should each show a resistance of around 5k ohms. Quote Link to comment Share on other sites More sharing options...
procharger Posted February 4, 2023 Report Share Posted February 4, 2023 I use an inductive timing light to see if the plugs are getting fire when it is messing up that has worked for me. At least I will know if I am getting a signal for lack of a better word to the plugs. The other thing I have done is strap all the plugs to the engine with cable ties turn over the engine in the dark and see If i get a pretty blue spark to the plugs. Just a suggestion I also have a Doctor Rotech testing box that checks all the coils and ignition modules. Quote Link to comment Share on other sites More sharing options...
procharger Posted February 4, 2023 Report Share Posted February 4, 2023 DR. ROTECH ENGINE DIAGNOSTIC TOOL from Aircraft Spruce Europe www.aircraftspruce.eu/dr--rotech-engine... Dr. RoTech eliminates time consuming diagnostic test procedures. Perform all required electrical tests for the Rotax 912/914 engine in a matter of seconds. No longer do you have to pull out your multimeter and fuss with connections and grounds to find out whether or not your Rotax 912 is in good health. Simply plug the Doctor into your ignition unit plugs and within seconds you’ll know which systems pass and which fail. Quote Link to comment Share on other sites More sharing options...
procharger Posted February 4, 2023 Report Share Posted February 4, 2023 I am also in Va. ken Quote Link to comment Share on other sites More sharing options...
Ken Posted February 6, 2023 Author Report Share Posted February 6, 2023 When I get back in town I would love to use your Rotech device. I pulled the plugs and they were all fine on the ohm meter. There were a couple of loose plug boots. I ordered some new ones and will replace them. I did tie wrap the loose ones and it made a difference. Completely normal run up at all rpm's. After about an hour of flight it was a bit rough on "mag 2". Thanks for your response. By the way, what is the fixture between the seats and above the pocket for? Quote Link to comment Share on other sites More sharing options...
procharger Posted February 16, 2023 Report Share Posted February 16, 2023 Not sure what you are asking about fixture. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted February 16, 2023 Report Share Posted February 16, 2023 On 2/6/2023 at 2:40 PM, Ken said: By the way, what is the fixture between the seats and above the pocket for? Are you talking about the cabin light? Someone could have added something else along the way too. Quote Link to comment Share on other sites More sharing options...
Anticept Posted February 16, 2023 Report Share Posted February 16, 2023 One thing to also keep in mind, the carbs orientation matters a lot, especially in the cold. If you get particularly sooty plugs on the front but not the back for example, try rotating the carb so that the top leans a few degrees outwards from the engine. I find quite a few carbs tucked inwards on flight designs. I fixed a mild roughness doing this. Quote Link to comment Share on other sites More sharing options...
cdarza Posted February 10 Report Share Posted February 10 I had an ignition module issue which I believe is the module itself going bad. After proper preflight and no issue run up i takeoff and 800ft in the air thought I heard a very slight drop in engine rpm but not consistent thus I was not sure I really had an issue. As I continued downwind to land I could hear what I thought was a very slight change in rpm but still not visible on the rpm gauge. After landing I tried switch 2 and no drop in rpm at all… switch 1 and the engine dies. I left plane overnight at hangar to troubleshoot the next day. On run up next day everything is perfect. Switch 1 a 50rpm drop and switch 2 also 50rpm drop. Although all was fine, i knew there was obviously an issue from the day before. 30minutes I was checking and rechecking and switched the “mags” over 20 times with perfect response …. Just as I was about to give up for the day i noticed a drop in rpm… I tried the switch 1, 2 again and voila … engine died on switch 1. I switched the plugs and the engine would now die on switch 2. So, I conclude a module problem … unless anyone has other suggestions to look into. oh I will add that I just assume module went bad after it got hot ?? It was fine on initial start and problem came about after engine was running for sometime. Or perhaps this is just coincidence Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted February 10 Report Share Posted February 10 Modules don't usually do this. They are either good or bad. Before spending any money I'd be looking for a bad wire. Look up on top by the modules and wires from the back of the engine that go there that have rubbed through their insulation. Check the red wire to the modules. Many times the vibration rubs through the wire insulation and that's why it's an intermittent issue. Quote Link to comment Share on other sites More sharing options...
DHeal Posted February 10 Report Share Posted February 10 When checking the module wires noted above by Roger, also check that the ignition switches and their associated wiring are working correctly. An intermittent ignition switch (e.g., internal failure) or intermittently shorting ignition control wire could cause the issue you are experiencing. Quote Link to comment Share on other sites More sharing options...
cdarza Posted February 10 Report Share Posted February 10 9 hours ago, Roger Lee said: Modules don't usually do this. They are either good or bad. Before spending any money I'd be looking for a bad wire. Look up on top by the modules and wires from the back of the engine that go there that have rubbed through their insulation. Check the red wire to the modules. Many times the vibration rubs through the wire insulation and that's why it's an intermittent issue. Thank you and I will check on this however, I did switch the module plugs and the problem did change from the switch 1 (engine dies) to switch 2 engine dies after I switched the module plugs … thus the possible bad wire would not be on the engine side correct ? The wires on the module side are all good (no signs of any wear or tear or rubbing on the insulation) I will reinstall today and check again. If I confirm 1 module is bad would it be fine to replace just the one module or is it recommended to change both together ? Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted February 11 Report Share Posted February 11 Because it switched sides it is from the back of the engine up to the modules. Check the easy to see wires from the top edges of the flywheel area up to the modules. I have seen and heard many times about a wire worn through and touching or a crimp on a connector so tight it cut the wire or and connector barely touching inside the plugs. You are right it isn't downstream of the modules. It is upstream of them. Just had a guy find a worn through wire that was rubbing on the metal case. Quote Link to comment Share on other sites More sharing options...
airhound Posted February 11 Report Share Posted February 11 Same general topic but for iS engines. From ROTAX.com - Introduction of new double ignition coils and new wiring harnesses for ROTAX® Engine Type 912 i (Series), 915 i (Series) and 916 i (Series) Say fella’s this SI just popped up. I got a 2013 iS within serial number range and was wondering how this upgrade improves the engine and ROM $…any insight appreciated. Doug in IL Quote Link to comment Share on other sites More sharing options...
cdarza Posted February 11 Report Share Posted February 11 I checked all the wires and couldn’t find any defects. On the run up today engine started fine and switch 1 and 2 “mag” drops were initially normal. About 10 minutes into the run up one mag had rough running and the other mag the engine died. Basically same as the other day although now one side runs rough (was smooth previously) and the other engine dies. I decided to check the sparks plugs - With Module A and B connected I wasn’t getting spark on cyl 1 and 2 lower and cyl 3 and 4 upper I disconnected Module B so only Module A connected and same results I then disconnected Module A so had only module B connected .. no spark on ALL plugs Seems like confirmation that module B is faulty. What I don’t understand though is why I’m now getting the rough engine on Module A and B connected when it was running smooth before. Anyways, will go ahead and get the new modules and see if this solves my issue Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted February 11 Report Share Posted February 11 It's not impossible that the ignition module failed in the running 26 degrees BTDC position, but fairly rare. It's usually in the start mode. Is there another Rotax engine around that you could borrow a module just for a test? Your other choice is to send it to Lockwood in Florida or to Rotec in Canada for testing. Quote Link to comment Share on other sites More sharing options...
cdarza Posted February 11 Report Share Posted February 11 Sadly no other Rotax engines nearby so my solution route is the expensive purchase of the module/s. At this point I’m really hoping it is the module so that I don’t have another issue to figure out - oh I forgot to mention that I had these modules serviced by Carmo 4 years ago.. (memory lapse) I forgot the details but I think it was similar. Thank you very much for your comments and suggestions. Will update soon. Quote Link to comment Share on other sites More sharing options...
cdarza Posted March 16 Report Share Posted March 16 Update - I received and installed the new modules and so far all good with the engine. I did check the “old” modules again and I was having 1 module fail on me after a 5 to 10minute run up. This has happened on about 5 separate run ups. All good for the first roughly 10 minutes and “mag” check all good … and then complete failure on 1 module. (Engine quit) So basically in my case, my 1 module is failing only after “warming up”. Quote Link to comment Share on other sites More sharing options...
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