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dmcewen

Member
I ran my engine above idle for the first time today. While checking the mag's at 4000 RPM with the "A" ignition switch off, had a 100 rpm drop, with the "B" switch off had a 500 rpm drop and the engine was quite rough. I am not familiar with the Rotax engine and need some help/ideas. Just walked away from it this morning, will go out Monday and pull the cowling and see if there is anything obvious.
Dick
 
Sounds like you are making good progress.

The engine snafu is minor and you should be able to correct.

1. Check the spark plug wires and make sure you have them on the correct cylinders, top and bottom plugs. The wires are marked. #1 Cylinder is right front (passenger side) (After all of the work we did on the engine it is fairly easy to get the wires crossed). If they are good go to step #2.

2. Check the connectors to the modules and make sure they are snapped togeather tight.

3. If those things don't do it you may need to recheck the gap on the pickup we moved when we attached the motor mount.
 
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Do what Larry says. I'm betting it is either crossed wires, or possibly just one wire not seated on the plug.
 
Larry Gerger e-mailed me and said I should report what I fornd. Went to the hangar and pulled the top cowl, checked plug leads and then pulled the top plugs. Plug in #2 cyl. was shorted. I don't know how it happened. All was well after I regaped the plugs.
Dick
 
DonFromTX said:
Shorted? Meaning the electrodes were touching or just fouled?
Click to expand...

From what I gathered the electrodes were touching. May be dropped the plug?

Anyway, that is great news that is was something simple. These engines are "almost" bullet proof, so having a mag drop and the engine running rough is unusual, and usually something simple.


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As a suggestion in the future, I was told to replace any plug that is dropped. The ceramic cone could be cracked and cause major damage to that cylinder if it come loose.
 
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