Originally Posted by ChrisRV12new
Taxi and flight test today were a success. I kept the power much higher during cold engine warm up.
Correct. Idle warm-up at higher speed is beneficial. I bring idle speed to ~ 2800 RPM as soon as engine starts.
• Cold engine runs smoother when speed is increased.
• Better for gearbox when engine runs smooth – no chattering.
• Smoother running is better for carb float level.
Let engine run ~3500 RPM for a minute or so prior to the 4000 RPM ignition drop test. This will normalize float levels that would otherwise contribute to large RPM drop.
Also, best to run fresh fuel. High-octane Mogas isn’t a big seller at gas stations, so it’s a little like a **** shoot when buying. I buy 93E10 for engine requiring 91 octane, so not much of a cushion there. Ethanol in the fuel is very volatile. The vented fuel tank allows air exchange. Alcohol will evaporate causing a reduction in octane, and because alcohol is hydroscopic, it will absorb moisture from the air which isn’t good either. If possible, use a Top Tier gas supplier.
Jim Stricker - EAA #499867
PPL/ASEL 1970 - Sport Pilot since 2007
80 hrs Flying Aeronca Chief 11AC N86203
1130 hrs Flying 46 Piper J-3 Cub N6841H
Bought Flying RV-12 #120058 Oct 2015 with 48TT - Hobbs now 650
LSRM-A Certificate 2016 for RV-12 N633CM
Special Thanks... EJ Trucks - USN Crew Chief A-4 Skyhawk
MJ Stricker (Father & CFI) - USAAF 1st Lt. Captain B-17H