Cherokee 180 ran rough

simtech

simtech

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Simtech
Was 45 minutes into a 1.5 hrs flight when the engine began to run slightly rough. Slightly like if your were leaning to until rough then riching it back up. Wasn't alot but enough for me and my passenger to notice. This was the second flight of the day after a quick turn. Was cruising at 6500ft 65% power leaned until rough then rich until smooth. I richend the mixture slightly and it ran smooth again. All gauges were showing normal operation. Rest of the flight was fine.

Never had that happen and trying to figure what might have happened. Maybe I should know this but does mixture requirements change in flight? I've been on long xc's and never had to readjust...just seemed odd in 2 years of owning this plane it's the first it has done this.
 
If it were my PA28-180C, the first thing would be to pull the plugs and check them for lead buildup. As an owner/pilot, you are allowed to do that yourself.
 
Good question. I don't know the answer. But one variable would be if density altitude changes over time or distance, then mixture requirements can change too. If you went from low baro press to high, you're leaner than you were, and if you go from high temp to low temp, you're leaner than you were. So if weather changes over time or in route, that might be a cause.
 
I would think it is possible for the mixture requirements to change in flight. Flying through a front for example should cause a pressure change, temperature change, density altitude change, etc. If you are right at peak or lean of peak, I could see where it might start having lean misfires if the change was drastic enough.
 
Pressure was changing along the route but not by a whole lot. Hmmm...I can check plugs but after that event all was fine the rest of the flight. I do lean aggressively and my plugs are usually never an issue. OAT temp changed slightly warmer as well...But again Ive never had to lean in flight like that before after cruise power set and initial leaning. Seems strange....or does it..haha
 
I hate those problems which you can't duplicate. Had that same exact thing happen to me in an Arrow. Just started running rough, engine in green, mixture seemed okay, flew back to home base and it never repeated itself. It STILL hasn't done that a year later.
 
Yep as long as it doesnt happen again or mean something bigger is manifesting im okay. Same flight this happened I lost my vacuum pump..:rolleyes:
 
Not saying this is your issue, but my PA28-181 had the same thing start happening last summer. We would be in cruise and at some point is would sound like there wasn't enough fuel going to the engine like I had leaned too much. It turned out that the massive spark plugs had over 800 hours on them. None of them looked bad when I pulled them, but I replaced them all anyway. That instantly cleared up my problem.
 
Were you flying over a large body of water?

If yes, that is just the "auto-rough" feature kicking in. Glad to know it is operating correctly! -Skip
 
Nope not over any water at all, but Ive flown over lake Michigan coming back from OSH and I know what you mean!

Could be plugs, Ive got about 100 hrs on these tempest plugs. They are the 38's and I should have put the 40's in.
 
I think you're just imagining this shet for a POA story. I you had an AOA in your plane you wouldn't be having these problems. Get DG to clean your plugs for you. :)
 
mscard88 said:
I think you're just imagining this shet for a POA story. I you had an AOA in your plane you wouldn't be having these problems. Get DG to clean your plugs for you. :)
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Im not sure id let DG near my plane, bad vibes for sure! Well we have an AOA in the sim if that counts?? haha
 
FlySince9 said:
may have ingested a bit of water?
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I did think that as well. Though I've already flown on that tank that trip...now I guess that doesn't mean anything though...thought ice too but I didn't do anything for that as far as carb heat is concerned. Had it been worse maybe..
 
I think the answer is actually pretty easy. You were flying to the Bahamas correct?
 
Hahaha I wish!! Instead I was flying over Alabama...I suppose that is why it ran rough...it doesn't like Bama..hehe
 
simtech said:
Hahaha I wish!! Instead I was flying over Alabama...I suppose that is why it ran rough...it doesn't like Bama..hehe
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If that's all it takes then I my Toga would run rough over Bama too... Woo Pig Sooie!
 
I noticed it warmed up but not a lot. Think it was 50f to 55f was the oat.
 
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