Again: engine start problems...

[Lewis - A2A]

Ok,

can you please list your entire procedure?

thanks,
Lewis

[Piper_EEWL]

Do you mean the start procedure?

Aircraft: cold&dark
Walk around: no issues apparent (fuel is not contaminated)
Enter cockpit:
1. switch on the fuel shutoff valve
2. Turn fuel selector to both
3. Switch on the batterie
4. Switch on the beacon
5. Check mixture in cutoff
6. Crack throttle
7. Turn on the fuel pump
8. Mixture full ritch
9. Wait till fuel flow is stable and immediatly pull back the mixture to cutoff
10. Turn ignition to start
--> engine cranks over but doesn't start.
I tried the same with leaving the mixture in longer at step 9 to prime some more but that doesn't do it either.
I checked the maintenance hangar if something's wrong. Nothing except a battery with low voltage and a burned out started after several attempts

Thanks

[Great Ozzie]

6. Crack throttle
7. Turn on the fuel pump
8. Mixture full ritch
9. Wait till fuel flow is stable and immediatly pull back the mixture to cutoff

Try backing up the .dat (so there is a fresh one) and see if this works:

6. Throttle less than halfway (around 45%)
7. Turn on the fuel pump
8. When you go to full rich - count 3 secs (a "one thousand one, one thousand two, one thousand three" - no pausing) then mixture idle cutoff & fuel pump off.

I have tried several times at EDDM with current FSX weather (29C) and it fires right up...

-Rob

[Piper_EEWL]

Hey Rob,

Tried your advise. But unfortunately no luck even with the new plane. I even tried more primer (talk 1005) but she won't start. And it doesn't say that it's flooded either...

Any more suggestions? I really don't know what I'm doing wrong. Especially since it works fine if the temps go down.

Thanks,
Sebastian

[Jacques]

I put an A2A Cessna 172 at an airport in Southern France with a Temp of 35 C. Using the usual procedure of priming for three to five seconds, then advancing the mixture as the engine catches did not work for me. The engine simply never caught. After numerous attempts with complete delete of the .dat file between attempts, I finally got a consistent start routine that probably isn't correct, or good.
Prime for three to five seconds and turn off pump. Turn on ignition and move the throttle to almost full on. Then move the mixture to just beyond half way or a little more. After a few revolutions the engine will catch. This is the only way I could get an engine start at these temps. I know it isn't correct, just reporting back what worked on my system.

[Piper_EEWL]

Thank you Jacques! I can confirm that. That's how it will start in those temps. Just not very elegant and for sure not the correct way.

EDIT: Just ran another test. Temp is now down to 22C / 71F and she started. So I think this can clearly be linked to temperatures.

Thanks

[Kimo]

Yes the A2A is really hard to start in hot temperatures. Takes a few starters and recharges to get it going

[AnkH]

Funny thing that I also use FS Global Real Weather and here in Switzerland, we have currently also 35°C. I will try this "non-elegant" startup as well, lets see if this is a solution. BTW: I always used "real weather" these days, so it is most probably also related to this issue on my PC. I will report back as soon as I know more...

EDIT: ok, did some tests. It seems to be related to the temparature in my case as well. Sadly, for me, the above "non-elegant" startup solution for hot temperatures does still not work, I simply get my C172 not started in those temperatures. A bug or a feature?

[Scott - A2A]

It sounds like you are flooding the engine. In really hot weather, you don't need to prime as much as in cold weather.

Just to test, next time you start in hot weather, DON"T prime and keep mixture RICH, and crack the throttle 20%. Crank the engine, THEN prime for a second or two, max and she should catch fine.

If you confirm the above, then when in hot weather, use the normal starting procedure but only prime for a second.

Remember the engine temps are persistent in real time, so even if you reload the plane, the engine temps are unchanged and you don't need to prime next time you start. It's really easy to over prime the fuel injected IO-360 in the 172, and if you do and if you don't use 1/2 to full throttle, that engine won't start. It will crank and crank and crank until the battery dies.

Scott.

[Kimo]

Wow I just got it started on the first try with a very short prime in 34℃. Thanks for the tip Scott.

[Piper_EEWL]

Ok thanks Scott. I will test tomorrow or Monday and get back to you.

Thanks for the advise.

[Oracle427]

Yes I agree that fuel injected (IO-360's) are much more finicky with priming over carburetor models. It may be counter intuitive to people who are familiar with fuel injection in modern automotive technology, but this is nothing at all like automotive technology.

[Scott - A2A]

I am going to admit here, as someone who has flown mostly carb powered planes, during one of our C172 test flights, I must have also over primed the engine using the normal 3 sec prime after shutting down the engine for just 30 min. I just didn't think it was flooded, and cranked and cranked the engine. Eventually, the battery died. I pulled the plane over and asked the mechanic for a "jump." He came over and said, "Scott, I'm sure you just flooded it - happens all the time. These fuel injected motors when they are turned off, are almost in a flooded state already. Just a little prime when warm and you flood the engine."

He hooked up the battery, held full throttle and cranked. After 5-10 seconds of cranking, "Vroooom" it started up.

And of course my immediate thoughts were, "I have to figure out exactly what happened so we can Accu-Sim this so people don't make the same mistake I just made." It took days of research and now because of this experience, our plane behaves very much like the actual plane.

And, I never came close to flooding that Skyhawk since, in game or for real

Scott.

[Jacques]

I'm almost certain this has come up before, but searching the forum didn't come up with any good hits on the ipad yesterday. Thanks for the reminder: one second of prime, if that, when hot!

[Piper_EEWL]

Ok guys,

I finally got around to test Scott's start procedure for the hot weather. I tried with both the C172 and the C182. Worked perfectly (as expected with advise from Scott ) Temperature is 30C/85F.

Thank you Scott. It's so much fun to deal with your products and just get them started can be a challenge. I've never flown a injected engine in RL but I'm sure that I'm prepared for it now

Well I think I'm gonna do some flying now