912ULS Won't Start

Why not try applying some heat to the ignition modules to see if it starts? Unfortunately if you only ever start the engine using both ignitions then a unit that fails to start the engine will be undetected. You only discover the problem when the second one fails resulting in no start. Having suffered from this problem myself I now start alternately on the left or right ignition so that I can detect the first failure.

I had this same problem after doing maintenance on the carburetors, the problem came from the fact that the throttle valves were not at full idle, so the choke did not work, and in the end no start

Jacques

Thank y'all for your inputs. I'm going to the airport this morning, on a much warmer day, and trying it again. My first check will be to look for spark plug function. I'll plug a new plug into the aft port side cylinder top cap, hold the plug against the cylinder head, and crank the engine. If there's no spark the ignition ain't working. As far as the throttle valves go, I've got 3 flights on the engine since working on the carbs and the only problem has been those 2 hard starts detailed in my first post above. Idle was fine and all other details of the flights had no decernable abnormalities. 

Alan

Will you be able to turn the prop fast enough to make modules produce a proper spark. With poor battery voltage it may not suffice. Perhaps a missing spark when tried manually just proves lack of revs.

Hi Peter. I keep a Battery Tender on it always. Yesterday I plugged a new spark plug into the cap, grounded it, and turned the key. The engine started instantly and the spark plug sparked. The bottom cap results were the same. I turned off the engine instantly each time. The difference between Monday's results from Saturday's was the 30 degree warmer temperatures. After talking to Lockwood I removed the modules and UPSed them for testing. Waiting. 

Alan