Hot Start - 1977 Piper PA-28-181 Archer II

Discussion in 'Flight Following' started by asechrest, Aug 25, 2014.

  1. asechrest

    asechrest En-Route

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    Joined a club recently, as some might have seen in my other thread. 1977 Piper PA-28-181 Archer II, Lycoming O-360 180HP.

    I've had enough trouble hot starting the plane that I thought I'd start a separate thread. Note that the club requires fuel top-off after each flight. So I end up landing, taxiing to the fuel farm, shutting down, topping off, then needing to fire it back up within 5 - 10 minutes to taxi to parking. So every flight for me will involve a hot-start, and I guess perhaps a flooded start if I screw it up? Here are the POH procedures for both:

    I note that the above is identical to the cold start procedure, with the exception of throttle 1/2 inch instead of 1/4 inch.


    I've had two flights now in the airplane, both with the CFI I got checked out with. On the first, he had to leave and I was left to fuel and hot start myself (the first time I'd done either; I lived a sheltered life during training at a full-service facility). Botched it and could never get it started. Pulled it to the parking spot in 95 degree weather. Ouch.

    Second flight the instructor stayed to play with the hot-start procedure. Tried by-the-book the first time and it failed. Handed over to the instructor and he tried once and failed. He then tried again, giving it two pumps of the throttle while cranking, and got it started after a few turns. Let it run for a few minutes then shut it down to have me try. Couldn't get it with the same procedure.

    --

    So, in this thread I hope for two things:

    1. An explanation of what exactly is happening internally with a hot-start, and why it's differen't and more difficult than a cold start
    2. What procedures you've found to work well for hot start in an O-360

    Thanks in advance.
     
    Last edited: Aug 25, 2014
  2. DesertNomad

    DesertNomad Pattern Altitude

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    I can't solve your problem, but I feel your pain. Today I went with my CFI for a flight in a Piper Turbo Lance (PA-32RT-300T). It was my first time flying this type. We needed fuel so I started it (no problem) taxied to the other side of the field for fuel and shut down.

    A hot start is supposed to be full throttle, mixture to idle cutoff. That almost worked… it ran for 3 or 4 seconds then died twice… then would not start. We waited 15-20 min and tried again. Same results. Over the next two hours we tried several times and almost had it a couple times. Eventually, the battery had nothing left to give and after a while we got a jump… after about a minute of trying and moving the throttle and mixture all over the place, my CFI eventually got it started.

    As I am looking to buy a share in this airplane it wasn't the best demo. ;)

    We flew it for an hour, parked it for an hour for lunch and afterwards the hot start worked perfectly.
     
  3. cowman

    cowman En-Route

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    Ok I own a 78 Archer II and I don't find my hot start and cold start procedures to be a lot different.

    I do find my airplane really likes it's primer to get going especially cold. Not sure about what you are all doing for procedures but this is what I do and my airplane starts relatively easily now.

    Cold-
    Master on, fuel pump on, mixture fully rich. 5 full pumps of primer, bump throttle up a little(1/2" is probably about right. I just bump it up a little from where it was at idle when I parked it last... and because I've flown it enough I just know where it should be). If it doesn't fire within about 5 seconds, stop cranking and give it 2 more pumps of primer. Starts like this every time.

    Hot-
    Same exact procedure except I only start with 3-4 shots of primer. If it won't start right off then give more primer. Always works by the 2nd attempt.

    I think the only way to flood would be pumping the throttle or doing too much primer... and I've never had an issue in this regard.

    It helps to be used to the airplane... you know exactly how much primer it wants, where the throttle should go, how it should sound/feel/etc. Also my field elevation is about 900'... I could see things being different if you're at a higher altitude.
     
  4. Scrabo

    Scrabo Pattern Altitude

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  5. JimNtexas

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    An O-360 should have no problem hot starting, none at all. You probably have an ignition related issue, unless you are flooding it with a lot of priming and throttle thrashing.
     
  6. Paulie

    Paulie Line Up and Wait

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    No prime crack throttle.
     
  7. GeorgeC

    GeorgeC Pattern Altitude

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    I was flying a PA28 180 for a while earlier this year and happened upon this article on priming.

    That said, the flooded start procedure listed above worked fairly reliably for me. There doesn't seem to be a one size fits all approach.
     
  8. Unit74

    Unit74 En-Route

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    Mine likes about 3 pumps on the go lever, starter engaged, pump as it turns and rarely does it not fire. If it doesn't, 2 squirts on the primer and pump the lever when starter is engaged.

    Most CFis with archer time know the throttle pump technique from my experience.
     
  9. SCCutler

    SCCutler Administrator Management Council Member

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    I honestly do not recall ever having trouble hot starting a carbureted engine; one thing you might try, though, is, as you are cranking the engine, slowly "sweep" the throttle from closed towards open. This way, at some point, you are likely to hit an air/fuel mixture at which the engine wants to run. Caution! Be certain that you are spring-loaded to pull the throttle back when the engine fires.

    Hot-start procedures for fuel injected engines are often more challenging, but an engine with a carburetor should never be particularly difficult.
     
  10. EppyGA

    EppyGA Touchdown! Greaser!

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    I have a Warrior, and had hot start issues. Had my A&P show me his technique. Mixture rich, pump on, master and pump the throttle half-way twice and crank.
     
  11. LDJones

    LDJones Touchdown! Greaser!

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    Try this: Idle at 1000 RPM for 15-20 sec. before shutdown. On restart, leave fuel pump off (there's already plenty of fuel available). Don't touch ANYTHING except the master and ignition! Crank. When she fires, move the mixture from cut-off position to rich.
     
  12. coloradobluesky

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    A few things you should know and probably do know, but if not here they are.

    Pumping the throttle puts MORE gas into the intake manifold. There is an accelerator pump that is activated by the throttle. This is to give the engine immediate boost of gas when you go quickly full throttle. It has the side effect of working when starting if you pump it. Generally, you shouldnt pump the throtte, but...

    Obviously pulling the lean knob all the way back reduces fuel intake. Makes sense to want that pulled back

    Going full throttle opens the air valve and allows maximum airflow. With no additional fuel, the evaporates the gasoline in the engine. If you are flooded you generally want that.

    Hope that helps.
     
  13. Cpt_Kirk

    Cpt_Kirk En-Route

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    That puts fuel in the wrong part of the system and does nothing but increase the risk for a fire.

    For hot starts in my Cont. IO-360, the mixtures stay forward, the throttles stay at idle, and I crank it over. If I starts and dies, I keep it turning and throw the pumps on low until it starts again.
     
  14. Mattl

    Mattl Pre-takeoff checklist

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    Having about 80 hours in 51H here is my recommendation.

    Throttle 1/4-1/2" open, fuel full rich, fuel pump on.
    Cold motor:
    Cold temp <40* 5-6 shots of primer and crank.
    Avg temp 45-75* 4-5 shots of primer and crank.
    Warm temp > 80* - 4 shots of primer and crank.

    Hot motor:
    Fuel pump on, mixture full rich, Throttle 1/2" open- 2-3 shots of primer
    While cranking if not firing, work the throttle to no more than half open. 1/2"-1/2open-1/2" over a 1 second time 2-3 times. Crank for no more than 10s at a time.

    Note: treat the primer like a syringe- when you pull it out, take your time, it has to draw the fuel in to it.

    Welcome to the club.
     
  15. JimNtexas

    JimNtexas Pattern Altitude

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    Starting an IO360 has nothing to do with starting an O360. You are correct to say that throttle pumping should be used with caution with carbs and never with injected motors.
     
  16. MAKG1

    MAKG1 Touchdown! Greaser!

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    Well, throttle pumping does absolutely nothing on an injected engine.

    So, no harm. It's kinda silly, though.

    There are SOME engines that do benefit from throttle pumping, some even safely. Not an Archer, though. 172RG POH's explicitly call for it (that's a sidedraft carb, though, so it's not filling the air box). I don't know why they don't just ask you to use the convenient primer. Maybe it fills all the cylinders instead of just one or somesuch.
     
  17. pilot_dude

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    Same problem in my -180. The procedure you mentioned worked every time. If I didn't pump the throttle it wouldn't start when hot. My primer was inop so if working that would have had similar results.
     
  18. asechrest

    asechrest En-Route

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    Thanks, Matt, for the warm welcome and the tips about the actual plane.
     
  19. asechrest

    asechrest En-Route

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    Thanks all for the input. I find the thread interesting. Couple of the most interesting things:

    1) Each plane seems to have its own quirks for hot-starting. This matches what my CFI and some others have said: you've got to learn what works for your plane. What I don't really understand is why one O-360 would be different from another.

    2) A common theme in these posts is warning against pumping the throttle due to risk of fire. But the plane I am flying would not hot start using the POH method of hot starting. It just wouldn't. Meaning if I use the by-the-book method, it seems I'll never be successful and will be pulling the plane to parking every trip. And yet, if you look above and in other threads, you'll regularly see people (including mechanics) relay successful hot-start procedures that involve pumping the throttle, and I can only assume they don't regularly start engine fires.

    So I am curious: if the general recommendation is not to pump the throttle due to fire risk, but the plane will not seem to hot start without doing so, what then? What does the "need" to pump the throttle to get it hot-started signify? My rudimentary (and probably wrong) thinking is thusly: "well, engine needed more fuel while cranking!" So would I have been better served by more shots of primer prior to cranking in lieu of throttle pumps while cranking? Or is throttle pumping providing fuel to a different part or in a different way? And does limiting the throttle pumping only to while cranking reduce the chance of fire?
     
  20. MAKG1

    MAKG1 Touchdown! Greaser!

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    Yes, you can use the primer like that. Just make sure it's locked when you're done.

    It squirts into the intake, rather than the carb, so it is quite different.
     
  21. cowman

    cowman En-Route

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    I've not felt the need to prime and crank at the same time but I suppose you can... make sure it's locked though. The engine will run badly if it isn't locked.

    As for the throttle thing... on my private checkride when I went for the primer to start my airplane the examiner stopped me and said not to do that and he showed me the throttle pump method instead. I wish I'd asked why now because he really knew Archers well. I've since used that method when my primer knob got stuck.... it does work.

    So as I understand it the throttle pump is not recommended because of risk of fire? How big is the risk? Throttle pumping is the standard starting method in the carbed automotive world and it doesn't seem to be an issue unless there's a backfire or something. Is this just being aviation paranoid or is there something different on an aircraft engine that makes this a greater risk?
     
  22. bcool

    bcool Pre-takeoff checklist

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    This is why young people don't want to learn how to fly....you have to do WHAT to start the engine??? :confused:
     
  23. MAKG1

    MAKG1 Touchdown! Greaser!

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    Yes, it is, but show me a car with an updraft carb.

    They are almost all downdraft, with the occasional sidedraft. No fire risk that way, as the fuel flows into the intake.

    The carb on your airplane (and the air box) is most likely on the bottom of the engine.
     
  24. asechrest

    asechrest En-Route

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    If the plane "won't" hot-start without pumping the throttle, what is the engine telling me?
     
  25. JHW

    JHW En-Route

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    Fwiw every time I've had a carb'd engine with chronic hot starting problems, it needed new mag condensers.
     
  26. Sam D

    Sam D Cleared for Takeoff

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    The POH procedure for my NA Lance ('76 - IO540) works every time. But it does take longer to crank than I'd expect (7-10 sec). Fuel pump off, mixture lean/cutoff, throttle open 1/2", crank then immediately enrich the mixture.
     
  27. JimNtexas

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    Exactly like our C177RG.

    For hot starts pretty much the same except don't prime it.

    The Cardinal Flyers Online recommend that for our IO360 motors that if we know we're going to hot start that we shutdown at 1200 rpm.

    Then when you are ready to hot start DON'T TOUCH ANYTHING! Just turn the key and be ready to ease in the mixture when it starts to fire. That works for me.
     
  28. MAKG1

    MAKG1 Touchdown! Greaser!

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    That your wallet is feeling heavy.
     
  29. asechrest

    asechrest En-Route

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    :lol: Well played.
     
  30. Mattl

    Mattl Pre-takeoff checklist

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    I think you're referring to the impulse coupling in the mags.

    OP - Give my method a go next time you go flying. Look at the club scheduling website and grab my cell phone number. If you have trouble again fell free to call me. I'm the VP.

    -Matt
     
  31. JHW

    JHW En-Route

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    No. Condensers means condensers. Impulse couplings are not affected by temperature.
     
  32. asechrest

    asechrest En-Route

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    Matt,

    Thanks, already have your procedure printed out and ready for my kneeboard. Gus has been great, too. I woke him up at the crack of dawn two Sundays ago when I arrived at the airport with the CFI but found the fence gate locked. He kindly directed me to the gate key already on my keychain. Woops! :redface:

    So far I'm really enjoying the club and the plane seems well cared for. Now that I'm checked out, can't wait to get to know the plane and area better. Also glad to see another club member here on POA.

    -Adam
     
  33. JHW

    JHW En-Route

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    This is a great example of the problem with clubs. Carbureted engines do not require a "procedure" to start. If this was your own airplane, you could just fix the problem with it. As it is, it sounds like you have to live with people who want to make it into something complicated
     
  34. asechrest

    asechrest En-Route

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    With respect, the plane's POH outlines "procedures" for starting - cold, hot, and flooded. So I'm not sure what you mean when you say there is no required procedure to start. It's also fairly clear from the responses here and in other threads that hot starting these engines can be finicky. Now, perhaps that is because all the people who have experienced this finickiness have been flying planes that need new mag condensers. I'm not sure and that level of engine knowledge is above my current pay grade.

    The club experience, of course, has pros and cons. Since I'd be unable to afford a comparable airplane on my own, I make some concessions for the privilege of shared airplane access. Namely, I don't get to do whatever I want. And yet, I get the impression that if a valid concern was brought in relation to one of the airplanes, the club would have no problem addressing it. I have deemed this an acceptable compromise.
     
  35. JHW

    JHW En-Route

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    Maybe it's not mags but it obviously needs something. Carbeurated engines start at the turn of a key with the throttle at idle. Lots of people are chiming in here with comments on started injected engines which is irrelevant.

    Personally I don't see how you tolerate an engine with such an annoying problem. Why not just fix it ?
     
  36. Mattl

    Mattl Pre-takeoff checklist

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    Adam-

    I quickly remember why I spent so little time on POA anymore.

    I doubt you'll see me post very often- if at all anymore. Enjoy 51H- she's a great bird.
     
  37. Gusecu

    Gusecu Filing Flight Plan

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    Haha... Matt, don't you love the ones jumping in to say there is a problem with the aircraft, when they don't anything about the aircraft. I never have a problem hot starting her... Have you?

    Adam- I'll give you a call to talk more specifics about hot starting the plane. I can also meet you out there and help you.

    Gus
     
  38. Ted DuPuis

    Ted DuPuis Administrator Management Council Member

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    Pump throttle once, crack throttle. Turn key. Ought to do it just fine.
     
  39. Mattl

    Mattl Pre-takeoff checklist

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    Never had trouble- but a little throttle manipulation always solved it not firing on the first attempt.

    She is a great plane.