Disconnected Spark Plugs

by David HEAL in 912 / 914 Technical Questions 7 years ago

It is my understanding that one should not rotate the crankshaft on a 912 ULS when the spark plug wires are not connected to the spark plugs -- doing so could damage the ignition modules. Is this also true if the ignition switches are in the OFF position?

Re: Disconnected Spark Plugs

by Bill Hertzel » 7 years ago

Bill Hertzel

13 1.95k 8k

If the ignition switches at OFF, there will be no spark.

If the switches are ON...
And you are turning the prop by hand at less than a few hundred RPM, there will be no spark. Or, you are turning the prop with the starter, the spark will find a ground somewhere. Not ideal, but not fatal.

If cranking the engine without spark plugs was going to damage the ignition coils, Ignition coils all over the world would need to be replaced every time a spark plug misfired, a plug connector came off, or a plug wire was damaged.

If you want to hand turn the prop with the switches OFF... Go for it!
If you want to crank it with the switches ON, the real danger is YOU getting shocked from the hanging leads.

Bill Hertzel
Rotax 912is
North Ridgeville, OH, USA
Clicking the "Thank You" is Always Appreciated by Everyone.

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