Hello everyone! I'm relatively new to the ownership world. I purchased my 182F about 1.5 years ago and I'm struggling to find any info on the issue I'm experiencing.

About 9mos ago, I began noticing that the engine sounded like it was "missing" occasionally when taxing or when power was pulled back in the pattern. By missing, it sounds as if a cylinder isn't firing occasionally. At the time, the aircraft was going in for annual so I brought it up to my mechanic. He felt that what I was experiencing was very common and not an issue of concern. I spoke to other 182 owners at my field and several stated that they experience the same thing. Ultimately, I began to feel like it was a non-issue.

The "missing" has continued without change until a couple days ago. I didn't notice any change during taxi or run-up. But with power pulled back and carb heat on in the pattern, the missing became much more noticeable. Partially pushing the carb heat in helped. This made me think that one or more cylinders may be running rich? Mixture was full rich in the pattern. Does that make any sense?

Thanks in advance

BG

Why full rich in the pattern?

That’s just what I was taught.

Sometimes the conditions you describe are caused by leaks in the intake system - gaskets or rubber couplers, etc. At closed throttle the suction in the intake system is greater and the amount of leakage air is a larger portion of total intake air than at higher power. The resulting lean condition can cause rough running.

I'd check all the rubber couplings in the intake system.
One of those on my 180 (RH side, just above the Y) had the habit of loosening up.
I finally drilled & safety-wired the thumbscrews on the clamps.

Cuffed and Hotrod - Thanks for the advice. I will start that investigation this weekend. If it is an intake leak, then carb heat shouldn't make the situation worse, correct? Carb heat should help?

Ditto induction air leak. Those clamps can loosen over time. You may have noticed increased fuel consumption as well.

As to full rich in the pattern, unless you’re doing touch and goes your engine will run better if you leave it at cruise setting and nudge it a little if the engine starts to get rough. You can land and taxi to the hangar like this and it will reduce lead build up on your plugs. Keep in mind if you go around you need to enrich the mixture depending on elevation. However the book sez land rich, but it doesn’t say when. So if you want to go by the book you could do a GUMP check on final when you push the prop forward. But keep in mind the elevation. If you’re landing at a density alt of 10k, full rich may not be a good idea.

Mudwagon wrote:Ditto induction air leak. Those clamps can loosen over time. You may have noticed increased fuel consumption as well.

As to full rich in the pattern, unless you’re doing touch and goes your engine will run better if you leave it at cruise setting and nudge it a little if the engine starts to get rough. You can land and taxi to the hangar like this and it will reduce lead build up on your plugs. Keep in mind if you go around you need to enrich the mixture depending on elevation. However the book sez land rich, but it doesn’t say when. So if you want to go by the book you could do a GUMP check on final when you push the prop forward. But keep in mind the elevation. If you’re landing at a density alt of 10k, full rich may not be a good idea.

Thanks Mudwagon! Sounds like it is time to pull the cowl. My field is at 3,600’. I do C-GUMP abeam the numbers. Pushing the carb heat back in made a noticeable difference in the missing sound. That’s a new feature.

My O-520 does the same thing. It is set up to run rich at high power settings because it needs the extra fuel then. At low power settings full rich mixture is already too rich. Applying carb heat has the effect of enriching it further. A warm day makes it worse. At your field elevation it is undoubtedly too rich at the lower power settings, especially on a warm day with high density altitude.

My technique is to leave the mixture leaned properly for the pattern altitude. I apply carb heat prior to power reduction and on short final I push in the carb heat and enrich the mixture to prepare for a go around. I never have carb heat on with mixture full rich at the same time.... or it will run rough and at reduced power. The other option is to land with carb heat on and the mixture leaned, knowing I have to push them in for a go around.

Check those intake fittings because that needs to be done anyway but I doubt if you have a mechanical problem based on your description. You are running too rich.

It's hard to break habits you were taught in the beginning (the old law of primacy)... but sometimes the techniques you were taught are not right for the current situation.

I think you need to lean your mixture.