Our Aztec has the little "spider" fuel distributor on the tops of the
IO540s. The fuel generally gets boiled out of it after shut down, so this
is what works for us.

1. All levers forward, throttles, props, mixtures.
2. Master on
3. Fuel pumps on until the fuel flow needles just barely wiggle... and I
mean just BARELY, all we want to do is fill up the fuel distributor, the
fuel lines, and send maybe a "titch" into the cylinders
4. Fuel pumps immediately off
5. Mixtures to idle cut off
6. Throttles cracked
7. Crank until it fires, mixture forward, add a little throttle, fuel pump
on
It normally turns over several more times than with a cold start and we can
tell when the engines are about to start by watching the blades slow as
compression builds, then they will fire.

We've tried the "full throttle mixture at idle cutoff, crank until it
starts" but it really drains the battery. Aluminum battery cables, 12v
battery located in the right side of the nose, just not a good combination
for cranking and cranking. Our owners manual even mentions starting the
left engine first. This goes back to the days when Aztecs and Apaches only
had an single alternator or single generator on the left engine. Barring
any other reason, it simply doesn't make sense to start the engine furthest
from the battery first if you have alternators on both engines. We start
the right engine first and let it provide extra cranking power to the
battery when starting the left.

What I try to teach people about hot starts is that the fuel/air mixture
will ignite best at one ratio and to think about how to obtain that best
ratio given the conditions. Just as we have to prime more or run richer
mixtures in cold dense air, hot starts and high altitude operations require
just the opposite. Less fuel for less air. We know that the engine is hot,
so the air in the cylinders is hot and very thin, right? So we don't have
to add much gas to obtain our best air/fuel ratio. Your technique of
bringing the throttle up halfway creates a leaner mixture by introducing
more air into the system, a leaner mixture is what we want but I would
rather start by restricting the amount of fuel, and possibly preventing plug
fouling. Work from a lean mixture towards a rich mixture rather than
working from a rich mixture towards a lean mixture and then back towards a
lean mixture.

I'd say to take a good look at your fuel system. Learn where the fuel is
boiling away and how to purge air and replenish fuel to that area without
adding fuel to the cylinders.

Jim



wrote in message
oups.com...
Hi there, I just got my Cessna 340. My right engine is very difficult
to hot start. I have to crank several times. Have done the flooded
start procedure which does not work, the only thing that seems to work
is to do a normal start, bring up the throttle halfway and if the
engine catches a little bit quickly lean out the mixture. But it is a
crapshoot and takes too much effort.

Any good tips and experiences?