Also keep in mind that these are air-cooled engines. Due to the configuration, it may very well be the case that one or both rear cylinders are not receiving th

Also keep in mind that these are air-cooled engines. Due to the configuration, it may very well be the case that one or both rear cylinders are not receiving the same cooling effect as the front two. Therefore, even if you're running lean of peak, it's very, very important not to overdo it On a Cessna 182 I used to run, I could lean it to 50-52 litres per hour, using a digital fuel flow gauge (not standard factory equipment). If I leaned to 48 litres per hour, the EGT gauges clearly showed a rise in temperature for certain cylinders. If I was leaning without using these gauges for assistance, it would be very easy to make a mistake and overdo it, or not lean enough and waste fuel/money.