You "primed a few pumps", I take it this means throttle pumping (accelerator
pumps?) on an already hot engine? I'd guess you did over prime and then
flood the engine.. I am not sure of your engine but I presume it is also an
IO-540? Always follow the POH or manufactures recommendations for your
aircraft or configuration, the Aztruck may not have the same throttle body
or injectors that you have.

On our Pawnee O-540, 250HP, no "injection", on a warm engine, one throttle
pump with the mixture full rich and back up to 1/2 throttle, left mag on and
hit the starter, starts in two blades reduce power and bring the right mag
online. I always shut down with mixture to idle cut off. Others tend to
prefer to run at idle and kill the mags for engine shut down, then they
touch nothing on restart but mags and starter, and it starts right up. I've
also seen raw fuel drain from the carb on their shut down technique.

On the Seneca II, the "book procedure" (cold engine) is mixture full rich,
throttle to 1/2. Electric primers to stabilize fuel pressure (about 4
seconds), release the primer and hit the starter, very smooth start. I've
found at higher airport altitudes and within an hour of landing, engine
still hot, this can tend to over prime or flood the engine very easily. But
then it's to the "flooded engine check list".

I had one airplane that was always hard to start... so when in doubt, flood
it and then do the flooded engine start.. worked every time.. because at
least then you knew what you were dealing with.

BT

"Jay Honeck" wrote in message
oups.com...
On our flight to Nevada, I was impressed with the smoothness and
car-like predictability of Jim Burns' start-up technique with his
Lycoming IO-540s. Jim had a way to start them that I'd not seen
demonstrated before, which I will describe he

1. Fuel pump on
2. Electric primer on for (a few?) seconds
3. Crack throttle
4. With mixture at full lean, start cranking
5. Gradually enrichen the mixture until the engine fires

(I may have some of this wrong, as the Aztec has nearly every switch
and gauge in bizarre, usually invisible locations...)

By using this method, his engines both started without cranking or
coughing, just like my Subaru.

So, of course, I've been experimenting with this method, which is quite
different than the one described in my POH. (Which basically says
"crank at full-rich"...) It has worked perfectly several times,
especially on hot starts, until yesterday.

Yesterday, after a short stop for a piece of pie ala mode at a nearby
airport, I primed a few pumps, cracked the throttle, and started
cranking with the mixture at full lean. I slowly enrichened the
mixture until the engine caught...at which point it ran VERY rough, and
did not want to stay running.

This condition continued until I LEANED the mixture back, at which
point everything returned to normal. I was able to slowly enrichen
back to full rich, with no further difficulty. Mag checks were normal,
and the flight home -- after a very careful and prolonged run up -- was
normal.

What happened here? Why did this technique induce an over-rich
condition? Theories, anyone?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"