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  #1  
Old 06-02-2019, 08:04 AM
scottmillhouse's Avatar
scottmillhouse scottmillhouse is offline
 
Join Date: Apr 2007
Location: Madison, AL
Posts: 322
Default Lycoming IO 360 flooding

Brand new Lycoming IO 360 from Vans on first start on my new 7A. This is my first experience with a fuel injected engine. Standard Vans Airflow Performance boost pump and Lycoming Precision stock fuel injection. Engine run only at factory. First if I leave the fuel injection boost pump on for more than a couple of seconds fuel flows briskly out the manifold overflow. Pressure shows up to about red line, about 40 with pump on which appears to flood engine. Will start then by cranking with mixture to cut off. Runs fine once cleared above 1000 rpm on engine fuel pump but will not idle being very rich and floods out unless mixture is pulled back 1-2”. Pressure from engine fuel pump also showing high 30s. Fuel system flows almost 1 gallon per minute on boost pump at either level or in climb attitude. Seems like there should be some type of pressure regulator.

Need to fix before taxi tests. Where to start trouble shooting?
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  #2  
Old 06-02-2019, 08:10 AM
jabarr jabarr is offline
 
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Are you running the boost pump with the mixture in the rich position? If so, yes it will flood the engine. Verify pressure readings with a direct reading gauge.
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  #3  
Old 06-02-2019, 08:34 AM
lr172 lr172 is offline
 
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pump on with mixture open is for priming the engine. As you noticed, it dumps fuel directly into the intake chamber. If you are seeing flow out of the manifold with the mixture knob at ICO, I would more closely examine your mixture cable linkage attachment to the servo and insure it is allowing it to reach the ICO position.

With a new pump, it may take a few minutes of running to break in the ball/seat area of the pump's pressure release. 40 PSI is well under the max that the a bendix FI can handle, so don't worry about it for a bit.

Larry
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Last edited by lr172 : 06-02-2019 at 08:37 AM.
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  #4  
Old 06-02-2019, 09:57 AM
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JonJay JonJay is offline
 
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As a side note, after several reports of backfires causing airbox “explosions”, I no longer prime my injected engine. Even a couple of seconds, as reported here, can flood, or at least put the engine in a very rich condition.
For cold starts, throttle cracked, mixture rich then back off a couple turns, boost pump on until you hear it load up (takes just a second) then crank. No more coughing and choking as it fires. It will take several blades before it kicks.
Safer procedure, although I did the standard full prime for more than 700 hours with no incidents.
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  #5  
Old 06-02-2019, 03:10 PM
N1Flyer N1Flyer is offline
 
Join Date: Apr 2009
Location: Port Orange, FL
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I have an IO-390 with the same issue. Based on input from very experienced friends, the procedure I've settled on is the following:

Cold Start: Throttle full and mixture rich. Prime for 1-2 seconds. Then retard the throttle so it's open about "1/2 inch" and bring the mixture to idle cutoff. Turn the key to start and as the engine starts, advance the mixture to rich. Idle the engine at a comfortable RPM (800 or so) and bring the mixture back at least halfway as you begin to taxi. Remember to bring the mixture to rich for the mag check.

Hot Start: Limit the prime to perhaps one second and repeat the above.

Personally, I think having an Earth X Battery has also made a big difference in starting. Just a thought.

These procedures have worked for me for quite a while.
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  #6  
Old 06-02-2019, 08:05 PM
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scottmillhouse scottmillhouse is offline
 
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ok from the collective wisdom then is this correct for start?

1. the boost pump is only used to prime with 2-3 seconds cold and 0-1 second warm. Not at all like carbureted engines when you could leave the pump on all the time. If you do this you are dumping fuel and flooding the engine.
2. Start with mixture shutoff and throttle forward 1/4" or so after initial prime.
3. When running richen mixture until smooth
4. Richen mixture to full for run up and then I assume keep it there for take off.

I assume then you lean mixture for cruise for best economy.

Full rich should not kill an engine in idle so I must have a problem somewhere.

If not for landing since full rich will kill the engine when rpm is reduced to idle, how do you select mixture position to keep engine running smooth and provide power for a go around if needed?
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  #7  
Old 06-02-2019, 08:11 PM
jabarr jabarr is offline
 
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http://www.precisionairmotive.com/Pu...IL%20RS-67.pdf
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  #8  
Old 06-02-2019, 09:12 PM
John Tierney John Tierney is offline
 
Join Date: Jan 2006
Location: Salem, WI
Posts: 292
Default Lycoming

From the operating manual, starting procedures begin on page 3-1 for various engine types:
https://www.lycoming.com/sites/defau...2060297-12.pdf
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  #9  
Old 06-03-2019, 12:23 AM
amerkarim amerkarim is offline
 
Join Date: Nov 2017
Location: Houston Tx
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Default Thanks

Quote:
Originally Posted by jabarr View Post
Thanks

This is just what I have been looking for

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  #10  
Old 06-03-2019, 08:56 AM
scrockard scrockard is offline
 
Join Date: Jun 2009
Location: Oregon City
Posts: 58
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Setting the mixture setting from that supplied link is extremely important and it frankly took up a lot of time for me on a partially broken in engine (just like your situation). You have to get that mixture set correctly so stick with it and set it correctly prior to first flight!

I will only prime (with boost pump) on a stone cold engine and then like already said, only until I hear a change in pump sound - 3-4 seconds (max) All other starts I do are "hot start" procedures with idle cutoff on mixture!

Cracking the throttle during priming will always result in easier starts for me but I've heard people say you are washing down the cylinder walls of oil doing this. I don't crack the throttle myself until after priming for the cold start case.

In case you are flooding an engine and potentially filling up a filter box with fuel, there is a safety precaution of putting a small hole INSIDE the filter area at the back to drain excess fuel for that excessive flooding/starting technique case. The second hole talked about is for a raining/parked outside case. I have both small holes in mine.

The most important procedure to master is learning to use the idle cutoff on starting when transitioning from carburetor to fuel injected!

Good luck and congrats to getting to the stage you are at!
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Last edited by scrockard : 06-03-2019 at 11:51 PM. Reason: lowered the priming time - agreed. 5 seconds is too long.
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