Engine Starting

Position and people. Before I turn the key:

• Airplane pointed so prop blast doesn't hit open hangars, people, or loose gravel
• Nothing and nobody behind me
• Brakes set or wheels chocked
• A loud 'CLEAR PROP' with a pause and a look before cranking

The pause matters, because someone may be moving toward the airplane the moment I yell (AFH ch 2).

Cold: the fuel doesn't vaporize well, so it needs priming — a few strokes of primer (or pumping the throttle per POH), then crank.

Hot: the engine usually needs little or no prime; over-priming a hot engine is the classic way to flood it.

Either way I follow the POH sequence, not habit.

Flooded means too much fuel, so I lean it out:

1. Mixture to idle cutoff
2. Throttle full open
3. Crank

The engine clears the excess fuel and fires — then immediately mixture rich and throttle back to idle. Full throttle with the mixture in is why flooded-start attempts sometimes end in a runaway RPM surprise; the mixture stays at cutoff until it fires.

Three limits govern starting:

• Starter duty cycle — crank for a limited time, then a mandated cooling period before the next attempt, because starters overheat and fail quickly
• Oil pressure — must come up within the POH time limit (commonly about 30 seconds, longer in cold weather) or I shut down
• Oil temperature/viscosity — considerations for very cold starts, including preheat when it's cold enough

• No oil pressure within the POH limit
• Abnormal noises or smoke
• An engine fire indication
• RPM surging uncontrollably
• A person or vehicle appearing near the prop
• The airplane starting to roll

Engine fire during start — the POH memory item is generally: keep cranking to pull the fire into the engine, mixture to cutoff, fuel off, and get the extinguisher if it doesn't go out.

Follow the POH exactly:

• Polarity and voltage must match
• Connection/disconnection order matters
• Avionics off during the jump, to protect them from spikes

The bigger question: why is the battery dead? A battery too weak to start may also be too weak to be a reliable electrical backup in flight, so I want the cause understood before I go flying, especially at night or into IMC-adjacent conditions.

Treat every prop as if the mags are hot — a broken P-lead means the engine can fire from a small blade movement even with the key out. I never let anyone stand in or walk through the prop arc, I brief passengers on it, and when I move the prop for any reason (which I avoid), it's with mags confirmed off, mixture at cutoff, and the same respect as hand-propping.