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[rkortge]

I'm having an intermittent engine sputter. Cant make it happen, however my engine seems to run differently from time to time. Mag checks on ground, in air, leaned all perfect. Not carb ice. Can't seem to do anything to make it happen, it just happens. Sometimes in cruise, sometimes in climb, never at low or reduced power settings. Can happen on back to back flights.Can happen twice in an hour, may go 50 hours without incident. No fuel leaks, primer operating correctly. Thinking it may be a carb issue or possibly a sticky valve. It goes away very quickly when it does happen, but it really gets your attention. Open to any suggestions. Thanks,
Rich Kortge # 82

[couleeone]

How many hours on your tach Rich?

[rkortge]

315 hrs. Geo

[txcub]

I'm having an intermittent engine sputter. Cant make it happen, however my engine seems to run differently from time to time. Mag checks on ground, in air, leaned all perfect. Not carb ice. Can't seem to do anything to make it happen, it just happens. Sometimes in cruise, sometimes in climb, never at low or reduced power settings. Can happen on back to back flights.Can happen twice in an hour, may go 50 hours without incident. No fuel leaks, primer operating correctly. Thinking it may be a carb issue or possibly a sticky valve. It goes away very quickly when it does happen, but it really gets your attention. Open to any suggestions. Thanks,
Rich Kortge # 82

Rich I use to have this also as you described, in fact my mechanic on field mentioned it one time as I went overhead. Intermittent as you described, but after having the cylinders worked on and using TCP additive, I haven't heard or felt it since. Not sure but my unscientific guess would be exhaust valves....?? Jon

[rkortge]

Thanks John , could you feel a roughness in your butt at times by any chance? I know that sounds strange but sometimes I can just feel something isn't right. Most of the time it runs perfect then I can feel something isn't perfect then it will slobber very quickly then go away. Did you have your top done because of that or we're compressions down?
Rich

[txcub]

Thanks John , could you feel a roughness in your butt at times by any chance? I know that sounds strange but sometimes I can just feel something isn't right. Most of the time it runs perfect then I can feel something isn't perfect then it will slobber very quickly then go away. Did you have your top done because of that or we're compressions down?
Rich

Rich Yes felt a roughness but it was VERY brief. Would always try to do a mag check to see but it never lasted long enough and it was very intermittent as you described. I had the cylinders reworked after having some lower compressions and leaks by the exhaust valves. Another indication was backfiring at idle on final and taxiing when we checked the first cylinder. Jon

[rkortge]

Great info thank you very much for weighing in.

[couleeone]

Rich, I have had a series of mag issues between 850 and a 1000 hrs and rebuilt them several times. This time I bit the bullet and replaced the left mag with a brand new one. Some of your problems could be caused by parts inside a mag, I have also recently replaced the spark plugs ( I had wire plugs) and spark plug harness as the shields were rubbing and wearing for intermittent firing.

Dont forget to check your alternator for play, if there is a lot of play replace the shaft bushing in the engine.

I have been giving dual to a snow bird customer in his carbon cub here in AZ. As much as I love my sport cub the carbon cub is that much better!

Rich, better call Randy for a demo it will knock your socks off! You can get your new panel you want that way too!

Post some more of your cool pics landing on the farms!

[rkortge]

Will do Geo. thanks for the tips.