For the Aztec drivers.... Starting hot engines

[Ted]

What I do on the 520s in the 310 is prime same as a cold start, mixture full rich, throttle full open, and then pull the throttle back while cranking (at the rate of FT-idle in about 3 seconds), and it catches around halfway.

Sometimes I have to do the Lycoming mentioned method on the 520s for a hot start, but rarely.

 

[comanchepilot]

that's not anything special. Everyone's "cookbook" is really the same thing. Flood the intake with fuel, then open the throttle while cranking to move a lot of air. The extra air will purge the excess fuel until it reaches a mixture that happy to light off.

'flood' might not be the right word - but most of the hot start procedures include idle cutoff and throttle open only 1/2 in - thats not enough . . . . nor is trying to start on vapor.

 

[JHW]

'flood' might not be the right word - but most of the hot start procedures include idle cutoff and throttle open only 1/2 in - thats not enough . . . . nor is trying to start on vapor.

sure it is. You can only run on vapor, you don't have liquid fuel in the cylinder. And the way you get that vapor is by evaporating your "flood" of fuel which is puddled in the intake

 

[Geico266]

Ted,

Well, after thinking your procedure may work I contacted Airflow Performance and asked them for the most current hot start procedure with the purge value option my plane has. Here is what they said.

HOT STARTS
* Mixture control "FULL RICH".
* Throttle ½ to wide open.
* Purge valve "OFF" position.
* Turn on boost pump and let run 30 to 45 seconds. This will purge the hot fuel and vapor from the system, and will cool and fill the fuel system components with cool fuel.
* Leave the boost pump on.
* Set Throttle to 1/8 open.
* Give engine a short prime by putting the purge valve to “run” then back to “off”. The amount of prime required my vary from installation to installation.
* Leave Mixture control "Full Rich”.
* With mags "HOT”, crank engine, when engine fires, return throttle to idle and purge valve to “Run".
* Leave the boost pump on during hot, low power, operation.

Another method for starting the engine when hot is to leave the mixture “rich” after purging the system. With the purge valve in the ICO position and the throttle at idle, crank the engine while slowly moving the purge valve to the Rich position. The engine will start during this movement to the Rich position.

So, I will now try this "new" method a couple of time and update the POH is it works better.

You can teach an old dog new tricks.

 

[Ted]

Gecko, sometime you'll have to show me this airflow performance system of yours. Glad you learned something.