Ignition Modules
Hi, First time user. I have a 912 uls, year 2006, 100 HP, serial number 5460xx. Engine ran good for a few flights this summer then suddenly no start. Narrowed problem down to no spark from either module high voltage side of firing coils to the spark plugs. I did the common high voltage side ohmmeter tests of the resister plugs, rubber plug caps, wires, and firing trigger coils by doing the across the engine plug boots from the cylinder pairs described in maintenance manual, with reliable ohm test results.
New plugs set at .024 gap, as advised setting from readings about better starting. Shortened spark plug wires at plug boots 1/4 inch before tests and re-connected firmly. I have measured the ohms tests from both sides of the plug connectors to the modules and to the pulse generator and firing coils. The tests are within the listed test diagrams in heavy maintenance manual. There are two other six-pin connectors on the heavy maintenance manual diagram next to the six-pin modules diagram. Where are those plug connectors? I used two heavy duty industrial double pole 250 volt/20-amp switches for each module P lead grounding wires to stop each module's ignition. I paralleled the wires on each switch for double ampacity and redundancy. The ohmmeter testing of those switches tested as I would have expected. Infinity for open and same ohms back to both modules from the switches. I did see an entry someplace from 912 uls owners having manufactured years 2006, 2007, and 2008 engines and experienced module failures after only short hours of engine time. My pictures show my modules are the green labeled types. Some fellow airport members also said the yellow labeled modules are the more robust type.
I have less than 500 hours on my engine since 2006. Well maintained engine and proper storage procedures in always kept un-heated hanger. Lots of medical issues preventing opportunities for me to fly. Are the modules energized all the time? Those second set of plugs in the diagram show a disconnect switch. I read about incidents from others who had destruction of modules from connecting even for a few seconds a battery charger in reverse polarity. I have one fuse to the ignition system at instrument panel and that is separated from power with a toggle switch at the instrument panel. I don't see how reverse polarity charge would be a problem for the modules if they are separated from power when a battery would be charged. I didn’t reverse polarity charge at any time, nor did I put any charger on the battery between my good flights and the no start day. Just another curiosity about something I don't understand. Are there any other fuses for the modules that I don’t know about? In addition, any suggestions about alternative ignition modules to the Rotax parts providers for after-market modules in the US that would be more economical than Rotax and any information about their reliability? When I did a search on the Internet for 912 uls 100 HP electronic ignition modules or capacitive discharge ignition modules, I couldn't even locate a source to find a price. I read they are expensive, but why aren't they listed anywhere?
I am from Wisconsin, near Green Bay. Anyone have information about any companies that test and sell these modules? Better yet would be technical reps that work for companies doing service for testing and selling the modules that I could contact for information first about steps for troubleshooting that I missed. I am assuming other tests will show problems with my modules that will be a costly fix. Any suggestions from guys who had similar experiences as mine, or anyone more experienced than me will be much appreciated.
Thanks for any advice in advance, Jim