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Thread: Tip for improved engine start (FX-3/fuel injected engines)

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    Lightbulb Tip for improved engine start (FX-3/fuel injected engines)

    There is no mention of throttle position during engine prime in the POH, nor was it mentioned during my TacAero training week, and in talking with other FX-3 owners, they've been doing the same thing as me, priming with the throttle all the way back or 1/2" from back/closed (start position). I enjoy watching YouTube videos of various flying and came across a Cirrus SR-22 video (normal aspirated) and noticed during his engine start he put the throttle to full open prior to doing the prime. The cluebird landed for me, duh, you need to open the throttle to allow the prime to flow, i.e. increased fuel flow position. I've had problems with starts such as priming 5 seconds, won't start, prime some more, eventually starts. i.e. multiple cranks to get a start.

    I tried the procedure of prior to engaging the fuel pump to put the throttle full open. My starts are fast now and never need a second turn of the key. I verified this situation with Pete at CC. Others have tried it as well after I mentioned it also with success. I would recommend the POH "template" be updated in section 4.3.2.2 to offer a throttle position in the engine start procedure prior to prime then prior to starter engage.

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    file:///C:/Users/davee/OneDrive/Documents/Carbon%20Cub/Manuals/Superior%20O360%20Engine%20Manual.pdf

    See section 4.3.2 of this Operating Manual and it explains it in detail. Its also in Section 4 of the POH.

    Engine Manual

    4.3.2 Engines Equipped with Fuel Injectors4.3.2.1 Perform pre-flight inspection.4.3.2.2 Set alternate air control in the “Off” position.
    4.3.2.3 Set propeller governor control in the “Low Pitch, Full RPM” position(where applicable).4.3.2.4 Turn fuel valve “On”.4.3.2.5 Open throttle approximately ¼ travel.4.3.2.6 Turn boost pump “On” (if installed).4.3.2.7 Move mixture control to “Full Rich” until a slight but steady fuel flowis noted (approximately 3 to 5 seconds) and return mixture controlto “Idle Cut-off”.4.3.2.8 Set magneto selector switch (consult airframe manufacturer’shandbook for correct position).4.3.2.9 Engage starter.4.3.2.10 Release starter when engine fires, if both magnetos are not on,switch to “Both”.4.3.2.11 Move mixture control slowly and smoothly to “Full Rich”.4.3.2.12 Check oil pressure gage. If minimum oil pressure is not indicatedwithin thirty seconds, stop engine and troubleshoot.4.4 ABNORMAL START PROCEDURES4.4.1 COLD WEATHER STARTING – During extreme cold weather, belowfreezing, it may be necessary to preheat the engine and oil before starting.Preheating normally takes 20 to 30 minutes to assure that all lines and allparts of the engine are uniformly warmed. Warm air should be forced upthrough the bottom of the cowl to reach the oil filter, sump area and intakemanifold. Additional heated air should be directed over the top of the engineto reach the cylinders and cooler. Once an engine is preheated, it can bestarted but should be run for 5 to 10 minutes at idle settings, not to exceed1,000 RPM. Verify oil pressure, which can take up to 45 seconds to rise tothe minimum of 20 psi. If a full minute goes by without reaching a proper oilpressure setting, the engine should be shut down and inspected.
    4.4.2 HOT STARTING – Engine hot start procedures are the same as describedin sections 4.3.1 (Carbureted Engines) and 4.3.2 (Fuel Injected Engines)except for the following.4.4.2.1 Omit priming.4.4.2.2 Set throttle control to approximately ½ travel and reduce to idlewhen engine starts.

    POH, Section 4

    4.1.1.1Hot Start or Flooded Start

    • IBBS switch ……………………………………….…On
    • Master switch............................................ ..................... On
    • Mixture........................................... .................... Idle cut-off
    • Throttle.......................................... ............................. Crack
    • Starter........................................... .......................... Engage


    After engine catches:

    • Mixture........................................... ........................ Full rich
    • Ignition Switch............................................ ................ Both
    • Throttle.......................................... ............. Set 1,000 RPM


    After engine has started:

    • Oil Pressure.......................................... ................... Check
    • Fuel Pressure.......................................... ................ Check
    • Throttle.......................................... ............. Set 1,000 RPM
    • Lights............................................ ................... As required
    • Avionics Master Switch............................................ .... On
    • Volts/Amps.............................................. ................. Check

    4.1.1.2Warm Up

    • Throttle.......................................... ........... 800 to 1,000 RPM



    Quote Originally Posted by hawgdrvr View Post
    There is no mention of throttle position during engine prime in the POH, nor was it mentioned during my TacAero training week, and in talking with other FX-3 owners, they've been doing the same thing as me, priming with the throttle all the way back or 1/2" from back/closed (start position). I enjoy watching YouTube videos of various flying and came across a Cirrus SR-22 video (normal aspirated) and noticed during his engine start he put the throttle to full open prior to doing the prime. The cluebird landed for me, duh, you need to open the throttle to allow the prime to flow, i.e. increased fuel flow position. I've had problems with starts such as priming 5 seconds, won't start, prime some more, eventually starts. i.e. multiple cranks to get a start.

    I tried the procedure of prior to engaging the fuel pump to put the throttle full open. My starts are fast now and never need a second turn of the key. I verified this situation with Pete at CC. Others have tried it as well after I mentioned it also with success. I would recommend the POH "template" be updated in section 4.3.2.2 to offer a throttle position in the engine start procedure prior to prime then prior to starter engage.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    I looked up the Lycoming IO-360 procedure as it probably more closely resembles the 363i. Your link, which could not be accessed was referencing the Superior engine. I couldn't find any mention of throttle position in the IO-360 search but I did see a thread over on SuperCub.org about a related topic which was more about hot starts (click here).

    I think the gist of the message I'm conveying in my findings, for "my plane" which may be different than others is if you're not cranking on the first attempt, analyze your prime procedure to see if you're getting sufficient fuel to the engine. Lycoming if I recall mentioned watching the fuel flow rise. I setup my G3X per how TSquared suggested to me which is to have your engine page come on at G3X power up. I just need to pay attention now to the fuel flow situation during prime and see what it's showing in various throttle positions.

    For me, taking note of throttle position during prime has given me successful starts on first crank on cold starts.

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    Sorry, I guess my link from my files didn't work.

    The Superior and the Lycoming is the same engine and have the same instructions. Here is a screenshot from the Lycoming manual stating the same. Like I said, also your POH manual gives (or should have) that same info as to starting, etc.

    Point being that, as you stated.....you have to open your throttle before the fuel will get into the cylinders when you run your boost pump. Every engine seems to be just a bit different but this 363i is a very easy starting engine and I've never had any problems with a hot start.

    I think the truest way of priming is to crack the throttle (cold start) and turn on the boost pump and then watch the fuel pressure gauge. As soon as you see it rising, shut it off. When cold it takes a bit more fuel it seems. I can usually count to 5 after turning on the boost and that's about right but watching the fuel pressure tells you fuel is running through the transducer which is at the inlet of the fuel servo. Careful not to run the boost pump too long with the throttle open as the excess fuel will run through the injectors and on into the intake manifold ....... and maybe go "boom"!

    Engines Equipped with Simmonds Type 530 Fuel Injector.
    (1) Perform pre-flight inspection.
    (2) Set alternate air control in “Off” position.
    (3) Set propeller governor control in “Full RPM” position.
    (4) Turn fuel valve “On”.
    (5) Turn boost pump “On”.
    (6) Open throttle approximately ¼ travel, movemixture control to “Full Rich” until a slight butsteady fuel flow is noted (approximately 3 to 5 seconds) then return throttle to “Closed” andreturn mixture control to “Idle Cut-Off”.
    (7) Turn boost pump “Off”.
    (8) Open throttle ¼ travel.
    (9) Move combination magneto switch to “Start”, using accelerator pump as a primer while cranking engine.
    (10) When engine fires allow the switch to return to “Both”.(11) Check oil pressure gage. If minimum oil pressure is not indicated within thirty seconds, stop engine and determine trouble

    A214276E-1D76-4E0B-A1E2-534EA98A3D61.jpeg

    Quote Originally Posted by hawgdrvr View Post
    I looked up the Lycoming IO-360 procedure as it probably more closely resembles the 363i. Your link, which could not be accessed was referencing the Superior engine. I couldn't find any mention of throttle position in the IO-360 search but I did see a thread over on SuperCub.org about a related topic which was more about hot starts (click here).

    I think the gist of the message I'm conveying in my findings, for "my plane" which may be different than others is if you're not cranking on the first attempt, analyze your prime procedure to see if you're getting sufficient fuel to the engine. Lycoming if I recall mentioned watching the fuel flow rise. I setup my G3X per how TSquared suggested to me which is to have your engine page come on at G3X power up. I just need to pay attention now to the fuel flow situation during prime and see what it's showing in various throttle positions.

    For me, taking note of throttle position during prime has given me successful starts on first crank on cold starts.
    Dave Embry
    "You only live once.......but if you do it right.........once is enough."..

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    Quote Originally Posted by hawgdrvr View Post
    There is no mention of throttle position during engine prime in the POH, nor was it mentioned during my TacAero training week,
    I like to call up the fuel computer page which shows the large fuel flow meter. The time I run the pump is based on how the flow meter responds. Prime duration should be based on the volume of fuel delivered to the injectors not a fixed time. The required volume will depend of environmental conditions. Monitoring the flow during prime also catches mistakes like having the fuel valve off or throttle closed.

    My AFM template does suggest a throttle position for prime. I have not checked the hardcopy in the aircraft but I suspect it is the same.
    Last edited by Andy; 03-22-2022 at 01:48 PM.

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    AFM template rev B:
    Attached Images Attached Images

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    Interesting Andy, my POH does not have a throttle position outlined nor does my TacAero provided checklist (but that is moot). I did a flight tonight and also video'd the engine start, haven't processed the video yet I'll see how it came out. Basically it seems with about 1/2" throttle the gph is around 3 and when you get to 1/2 or full throttle, it's around 6 gph, same for both positions. I'm curious of what the rated flow rate is on the fuel pump.

    No issues to date with a hot start, just cold start I've had times where I've had to prime more, try 2-3 times, etc. (in winter ops). Since I've been opening the throttle during prime it's 100% solved my issue and I get great starts on first crank and that's all I really wanted to share. So in summary, make sure the throttle is at least 1/2" open during prime and it may help others.

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    Quote Originally Posted by hawgdrvr View Post
    I'm curious of what the rated flow rate is on the fuel pump.
    Andair provides test data with each delivered pump. Test data for one such sample include:

    Open flow rate (USG/Hr) 39.5
    Closed flow pressure (psi) 34.5

    At takeoff the engine can consume over 18 gph at about 28 psi. Part of that is contributed by the engine driven pump in normal operation but, if the engine driven pump fails, the electric pump has to be able to deliver at least that much fuel.

    The flow during prime is not limited by the fuel pump. It is limited by the fuel injection servo and the settings of mixture control and throttle.

    I have over-primed a couple of times and, while the engine started, it was rough for several seconds before it burned off the excess fuel. Best to under prime, crank for a couple of seconds, and if it does not start prime a bit more.

    I find the 363i to be one of the easiest engines to start I have ever operated. I suspect that at least part of that is credit to the ignition system. if it doesn't start in 2-3 seconds you are doing something wrong.
    Last edited by Andy; 03-22-2022 at 07:10 PM.

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    Quote Originally Posted by Andy View Post
    AFM template rev B:
    I showed the incorrect checklist for G3X equipped aircraft. Here is the correct one which specifies IBBS On before Master On. It does not show throttle 1/2 inch before prime which appears to be an error.

    I turn on IBBS as soon as I get in the aircraft. By the time I have the seat belt on and my knee board in place the G3X boot has completed and I can record the pre-start times and cross check fuel remaining against the sight gauges.
    Attached Images Attached Images

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    Default Re: Tip for improved engine start (FX-3/fuel injected engines)

    Good catch, and yes that's what I have as well. No mention of throttle position and as discussed open 1/2" or more to get prime into the engine is the trick, for me.

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