Starts fine, idles fine, but after running on plane for a while will only idle on 3 cylinders. If I briefly choke it starts to idle al 4 cylinders for a second then stops firing. I have changed fuel/water filter plugs. I did have one time that it started to slow when on plane but kept running. If I take it for short run like 5 minutes the problem does not happen I have to run it for a while. The last time running it also would bog on transition from idle to full throttle actually stopped I could restart but running on 3 cylinder unless hitting choke briefly. I was going to find which cylinder was causing problem by holding hand over each carb to see which ran when choked the rebuild possibly fuel pump as well.
