Hot Starting Fuel Injected Engines

Rick Durden wrote:

You may have bent a connecting rod.

I think that unlikely considering the quality of the flight after he did get it
started.

George Patterson
A woman's perfect breakfast occurs when she's sitting at the table sipping
gourmet coffee while looking at pictures of her son on the cover of Sports
Illustrated, her daughter on the cover of Business Week, her boyfriend on
the cover of Playgirl, and her husband on the back of the milk carton.

On 14 Oct 2003 18:35:19 -0700, (Rick Durden)
wrote:

Corky,

You did describe what sounds like hydraulic lock. It can happen on
horizontally opposed piston engines if the engine is overprimed. You
may have bent a connecting rod.

All the best,
Rick

I sure hope not. The engine did start and run normally after that,
with no vibration or noises.

I did mention that I did not use the auxiliary fuel pump for the start
didn't I? Repeat, did NOT use the auxiliary fuel pump.

All I did was crack the throttle and attempt the start. I do not know
for how long the airplane was sitting prior to me getting there but
the engine was hot to the touch. There should have been no residual
fuel in the combustion chambers, unless the injectors somehow leaked
down after the shutdown. This engine is virtually brand new so I'd
hope the injectors aren't leaking down.

Corky Scott

George,

Damage from hydraulic lock sometimes shows up immediately (friend of
mine had the engine fail within 45 minutes after the lock) and some
does not show up for many hours, or even until overhaul. I just hope
he did not damage the engine.

All the best,
Rick

"G.R. Patterson III" wrote in message ...
Rick Durden wrote:

You may have bent a connecting rod.

I think that unlikely considering the quality of the flight after he did get it
started.

George Patterson
A woman's perfect breakfast occurs when she's sitting at the table sipping
gourmet coffee while looking at pictures of her son on the cover of Sports
Illustrated, her daughter on the cover of Business Week, her boyfriend on
the cover of Playgirl, and her husband on the back of the milk carton.

Rick Durden wrote:

Damage from hydraulic lock sometimes shows up immediately (friend of
mine had the engine fail within 45 minutes after the lock) and some
does not show up for many hours, or even until overhaul.

I'm just thinking that a bent con-rod should show up as vibration. At the least,
you'll be getting less compression and power out of that cylinder.

George Patterson
A woman's perfect breakfast occurs when she's sitting at the table sipping
gourmet coffee while looking at pictures of her son on the cover of Sports
Illustrated, her daughter on the cover of Business Week, her boyfriend on
the cover of Playgirl, and her husband on the back of the milk carton.

Corky,

Thanks for the clarification. Not using the boost pump would tend to
rule out a hydraulic lock event on a horizontally opposed engine.

All the best,
Rick

(Corky Scott) wrote in message ...
On 14 Oct 2003 18:35:19 -0700, (Rick Durden)
wrote:

Corky,

You did describe what sounds like hydraulic lock. It can happen on
horizontally opposed piston engines if the engine is overprimed. You
may have bent a connecting rod.

All the best,
Rick

I sure hope not. The engine did start and run normally after that,
with no vibration or noises.

I did mention that I did not use the auxiliary fuel pump for the start
didn't I? Repeat, did NOT use the auxiliary fuel pump.

All I did was crack the throttle and attempt the start. I do not know
for how long the airplane was sitting prior to me getting there but
the engine was hot to the touch. There should have been no residual
fuel in the combustion chambers, unless the injectors somehow leaked
down after the shutdown. This engine is virtually brand new so I'd
hope the injectors aren't leaking down.

Corky Scott

"Paul Sengupta" wrote in message .. .
snip

How does it happen to be that the standard hot start procedure for
my plane (fuel injected Lycoming 360) and I believe many others is:
no priming, throttle to max, mixture to idle cut off and crank...when it
fires reverse the throttle and mixture (works like a dream on my plane
by the way). Now this is basically the flooded engine procedure...
so how come there's fuel in the cylinders/manifold on shutting down a
FI engine by leaning the mixture?

Fuel "out" of the servo is shut off by the mixture control at ICO. If
the Brand L in question has an external flow divider, the valve in the
flow divider closes also.

The engine quits because of the "finger over the soda straw"
principle, there is still fuel in the injector hard lines, it just
stops flowing out the nozzle end when the inlet end is stopped up.

The heat-soaked engine compartment eventually drives the fuel out of
the hard lines either as liquid fuel, or more likely as fuel vapor.
Catch it just right and you can hear it "bubbling".

Fuel ends up in the intake port of the cylinder, or in the induction
system, where it is waiting patiently for a suck-squeeze-spark.

TC

Here's the way I was taught to hot-start the 180hp Lycomings in the Skyhawk:
Follow the check list procedure for a normal (first time today)
start.....

That is:
Advance throttle 1/4 inch
Mixture to idle cutoff
Master switch on
Fuel pump on
Push in mixture control to see positive fuel flow on the gauge
Mixture to idle cutoff
Fuel pump off
Crank the engine
Shove the mixture control to full rich when the engine starts
Adjust throttle for 1,000rpm

It works for me. Even when the OAT is 3-digits

Hot start procedure for my Trinidad (Lycoming IO 540 C4 DD 250hp) is
fuel pump on, throttle full open, mixture to full rich for 1 second or
positive flow then closed, fuel pump off, and when the engine fires
mixture to full rich. Simple & works every time.

Bex


--
bex
------------------------------------------------------------------------
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Ah, thanks! The follow on question is then...

We stop the engine by moving the mixture to ICO. Now all
the books, etc, say that this is so that there is no fuel left to
ignite if there's a live mag, so the engine won't start. Now if
an FI engine leaves fuel ready for the next start, then a) it's
more dangerous if there's a live mag, and b) would switching
off the ingition be any different in this case? Would it leave
the engine too flooded?

Paul

wrote in message
om...
The heat-soaked engine compartment eventually drives the fuel out of
the hard lines either as liquid fuel, or more likely as fuel vapor.
Catch it just right and you can hear it "bubbling".

On Fri, 17 Oct 2003 03:40:48 GMT, "Casey Wilson"
wrote:


Here's the way I was taught to hot-start the 180hp Lycomings in the Skyhawk:
Follow the check list procedure for a normal (first time today)
start.....

That is:
Advance throttle 1/4 inch
Mixture to idle cutoff
Master switch on
Fuel pump on
Push in mixture control to see positive fuel flow on the gauge
Mixture to idle cutoff
Fuel pump off
Crank the engine
Shove the mixture control to full rich when the engine starts
Adjust throttle for 1,000rpm

It works for me. Even when the OAT is 3-digits



Casey, you just described what the Skyhawk POH says is the "cold
start" procedure.

The POH specifically says to eliminate the use of the fuel pump for a
hot start.

Did you read that out of the POH, or is it something taught to you by
your instructor because he/she found it worked better?

Thanks, Corky Scott