Give me carbed or give me death!

[gkrangers]

Seriously, why are these god damn fuel injected 172s such a bitch to start sometimes?

Today, started right up. A few hours later, starting it again, took me over 30 minutes and 10+ tries.

Whhhhhyyyyyyyyy?

*goes to corner to cry*

 

[GravityHater]

Post your normal and hot-start procedure, maybe we can discuss alternative methods

 

[viper548]

sounds like you're doing something wrong if it's taking you 10 tries to get rid of vapor lock

 

[MTpilot]

Hot start; try mixture idle cutoff, throttle full, crank til it kicks, then, mixture rich and throttle a thousand or so. I think thats right.

 

[GravityHater]

No prime?

Hot start; try mixture idle cutoff, throttle full, crank til it kicks, then, mixture rich and throttle a thousand or so. I think thats right.

 

[EagleRJ]

Hot start; try mixture idle cutoff, throttle full, crank til it kicks, then, mixture rich and throttle a thousand or so. I think thats right.

That's actually the flooded start procedure, but a lot of times that will work if you get too enthusiastic trying to start a vapor-locked engine.
I've never flown a FI Skyhawk, but I usually had luck starting the bigger FI engines by using as much prime as I could get away with to get some cool fuel in the lines. If I went too far and flooded it, the vapor lock was cleared, so I just did a flooded start and it usually fired right up.
Don't flood it on purpose- that's bad operating procedure and will cause accelerated wear- but if that's where you wind up, you can still get the engine started if you know what's happened.

 

[jackotron]

If it is really hot, sometimes I leave the fuel pump on low, mixture full lean and throttle to full. Crank the engine, when it catches, bring the throttle back, mixture in and fuel pump off.

Sorry that it took you ten tries. It took me almost that long to get it right one day, I sure felt like a jacka$$.

Jack

(kind of ironic huh?)

 

[viper548]

If it is really hot, sometimes I leave the fuel pump on low, mixture full lean and throttle to full. Crank the engine, when it catches, bring the throttle back, mixture in and fuel pump off.

Sorry that it took you ten tries. It took me almost that long to get it right one day, I sure felt like a jacka$$.

Jack

(kind of ironic huh?)

That always worked for me

 

[gkrangers]

sounds like you're doing something wrong if it's taking you 10 tries to get rid of vapor lock

its a damn cessna...i tried everything several times.

finally got it to start going with no fuel pump, mixture rich, throttle open a touch, I think...can't even remember which configuration got it too work.

Normal: throttle open 1/4", mixture rich, pump on for a few seconds, pump off, mixture idle cutoff, ignition...advance mixture when it starts.

hot: throttle full, mixture idle cutoff, start.

They have been giving me issues lately at times....last spring I had no problems whatsoever with the SPs.

And the term vapor lock is thrown around a lot, but what is it exactly and how do we get rid of it ?

I know I'm showing my inexperience here...but damn, I've never had to try more than 3 or 4 starts till tonight.

 

[minitour]

And the term vapor lock is thrown around a lot, but what is it exactly and how do we get rid of it ?

The fuel injector is on top of the engine. When the engine is run and is sitting there after shutdown, the heat goes up. The fuel in the injector "lines" vaporizes because of the heat. You need to send some "cool" fuel into the lines so you have liquid in there.

Your hot start listed above sounds like a flooded start.

For a normal hot start (engine was running recently), try doing the normal start only without the priming steps. That's the procedure for the 172R (IIRC) and it seemed to work well.

If it doesn't start, just let it cool for 30 minutes (I know the delay sucks but...) and it should start fine for ya.

How'd the DUATS thing go?

-mini