Carburetor Hot Starting

D

DBoss11

Filing Flight Plan
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Jul 30, 2020
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DBoss11
Hi all,

I'm getting checked out in a Cherokee 180, everything I've flown to this point in my life has been fuel injected, and I've got a question about starting with a carb. For a cold start, the process seems pretty simple, prime 3 times, mixture full rich, slightly crack the throttle and crank, but for hot starts whats the procedure? POH says to pump the throttle three times, but everything I've read online says to avoid pumping the throttle as the fuel pooling from the accelerator pump can cause a fire easily if the engine backfires.

Do you prime again for a hot start? Or mixture full rich, crack the throttle, see if it starts, and if not then prime?

Thanks for the help in advance
 
Try full throttle, mixture at idle cutoff.When it fires, swap t.hem quick. Works for me
 
Every engine is different. For cold starts, I would recommend priming the MINIMUM amount that results in an easy start. You can always add more prime. If you flood the engine, it's a lot harder to start from there. Usually the POH or owner's manual provides guidance, but it's usually pretty non-specific, like "prime 1-3 times as necessary." For hot starts, you can typically start without priming, with maybe one throttle pump while you are cranking. For the three carbureted Lycoming engines I have flown behind, this has always worked. Pumping the throttle before cranking is not recommended. If you want to add fuel before cranking, use the primer.

You can ask the aircraft owner or your instructor what they usually do to start this particular engine for guidance.
 
My experience is like @chemgeek 's. From my observation, starting issues more often seem to come from having too much fuel available, not too little fuel. If the engine is warm, I'd try to start it without priming, and prime only if that doesn't work.

And yes, every engine (and engine installation) is different, so the above is not valid everywhere.

- Martin
 
It's a fine line between primed and flooded with hot engine, or even just hot weather. Pull primer out, start cranking. If it doesn't fire on its own, push the primer in.
 
Carbd lyco 360 and carbd lyco 540 hot starts for me have been mixture rich, fuel pump on, throttle open a little, crank and it fires up immediately.

And that's been the same with outside temperatures from -10 degrees Fahrenheit to +115 degrees Fahrenheit
 
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