Piper Arrow Hard to Start

ARFlyer

ARFlyer

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I want to see what you guys think of this problem and what is causing it. If you fail to get the plane started on the first try it becomes impossible to start. It will either have fuel pouring on to the ground or won't have any fuel at all. The plane will kick on a flood start and keep kicking with the key on both. However after about two or three wimpy kicks it will die. We have tried every mixture and throttle setting known to man. Prime it for two second or five have both been tried. Priming with the throttle full and mixture rich, throttle cracked and mixture rich both give the same results. The engine either back fires or has a womp womp sound like its flooded. AFter about 10 second on the starter it gets a horrible whining sound. When that sound hit the engine will not kick afterwords. The plane is easier to start cold, but once its shut down warm after the first flight this problem starts.

Any ideas guys? If you need more infomation just ask.
 
Not really sure what your problem is but, priming with the throttle is a good way to start an engine fire :) I would nix that from my "list of things to try"
 
I have an Arrow II with an IO-360. Arrows are notoriously hard to start when hot. Here is what my mechanic says and it has worked for me.

Of course, assuming there is nothing wrong with the fuel system:

Kill it with the mixture when you shut it down.
DO NOT touch the mixture until the engine is running again, leave it full lean.
Crack the throttle.
Crank and as it starts (after it starts), advance the mixture.

His explanation is that the closed mixture control traps the liquid fuel that is in the line and if you open the fuel system hot (by advancing the mixture), it will vapor lock. I would have to look at a schematic to see if that makes sense but it has worked for me and, with an Arrow, I am not messing with success.

Oh, and have the starter checked. I just replaced my starter and ring gear with a Hartzell E-Drive and new ring gear. One thing I like about my mechanic is he is fine with me shopping around and buying the part myself. He even picked it up at the distributor for me :) Saved me over $300.

http://www.hartzellenginetech.com/aircraft_starter.html
 
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bartmc said:
Not really sure what your problem is but, priming with the throttle is a good way to start an engine fire :) I would nix that from my "list of things to try"[/QUOTE

If I recall I think that is the only way to prime it and the method recommend by the POH.

Brian
Click to expand...
 
bartmc said:
Not really sure what your problem is but, priming with the throttle is a good way to start an engine fire :) I would nix that from my "list of things to try"
Click to expand...

Sorry if that caused confusion. We prime with the fuel pump. The throttle part was trying to describe throttle and mixture positions during priming. One is the POH setting and the other is the engine manuel setting

My friend showed me that I forgot to say that this is happening both of our Arrows.
 
brcase said:
bartmc said:
Not really sure what your problem is but, priming with the throttle is a good way to start an engine fire :) I would nix that from my "list of things to try"[/QUOTE

If I recall I think that is the only way to prime it and the method recommend by the POH.

Brian
Click to expand...

"Priming" with the throttle would be using the accelerator pump in a carbureted engine. You cannot "prime" that way with an FI engine like the Arrow. My club C-172s have a priming pump and I seem to be the only one that uses it. Everyone else pumps the gas. I find that doing it by the book works just fine. The Luscombe you prime with the throttle and then pull four blades to charge the cylinders (hand prop).
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ARFlyer said:
Sorry if that caused confusion. We prime with the fuel pump. The throttle part was trying to describe throttle and mixture positions during priming. One is the POH setting and the other is the engine manuel setting

My friend showed me that I forgot to say that this is happening both of our Arrows.
Click to expand...

Try the method I gave you above.
 
Try this. Throttle & mix full forward, hit the fuel pump switch, watch the fuel pressure gauge. When the needle stabilizes at its pressure easy count of 3 (longer if cold) and switch off. Pull the mixture back to lean, throttle open an inch and start cranking, when it chugs bring the mixture in and bring the throttle to 900-1000 rpm until clear and solid then lean back hard and idle down to as low as it will run smooth.

You may want to start by cleaning the plugs because they are likely pretty loaded up.
 
Same basic engine in the M20J. We used to do every hot start, including the FIRST one, as a flooded start. Five seconds with the pump on, Mix to cutoff, throttle about half open, crank. Worked vERY well.

Also check and make sure your Impulse coupler isn't worn. It's a notorious problem when the spark isn't right.
 
Good procedures given above,

If still very difficult some places to look for problems.

Weak mag with the Impulse coupling, or even the wrong IC, yes I've seen it.
Torn diaphragms on the fuel servo, this can be checked by having the mechanic take the air inlet off, and running the pump with the engine set to ICO, if fuel goes into the air intake, you have a problem.
 
Henning said:
Try this. Throttle & mix full forward, hit the fuel pump switch, watch the fuel pressure gauge. When the needle stabilizes at its pressure easy count of 3 (longer if cold) and switch off. Pull the mixture back to lean, throttle open an inch and start cranking, when it chugs bring the mixture in and bring the throttle to 900-1000 rpm until clear and solid then lean back hard and idle down to as low as it will run smooth.

You may want to start by cleaning the plugs because they are likely pretty loaded up.
Click to expand...

That is the procedure I use to cold start. I am pretty sure that will flood the engine badly if you try it hot.
 
Flew to a local club's monthly $100 burger for my first time and asked a fellow with a '76 Arrow II how he handles hot starts.

If it was just turned off, he does it same as me. And I had to restart right after shutting it off today and it started fine. If it has been 30-60 minutes, here is his technique

Again, kill it mixture and do not touch the mixture again.
Run fuel pump 10-12 sec. Do not touch mixture.
Throttle 1/3 to 1/2.
Crank and after it starts to catch feed mixture slowly until it runs smoothly, leave the mixture there for taxi.
Throttle back.

Pretty much the same as me except for the running the fuel pump and more throttle than I use.
 
alfadog said:
That is the procedure I use to cold start. I am pretty sure that will flood the engine badly if you try it hot.
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The biggest problem people have hot starting engines is not flooding the system with fresh cool fuel before trying to start. That's why they recommend flooding the engine with fuel and using the flooded start procedure if you are having trouble with a hot start.
 
Try putting the mixture full rich, throttle half open and start cranking with the fuel pump off, when the engine picks up immediately turn the fuel pump on and adjust the throttle. Works for me on virtually every hot start at the first try.
 
cirrusmx said:
Try putting the mixture full rich, throttle half open and start cranking with the fuel pump off, when the engine picks up immediately turn the fuel pump on and adjust the throttle. Works for me on virtually every hot start at the first try.
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Might be worth a shot but it's going to result in a flooded engine 100% of the time on our arrow.

YMMV
 
The logic behind the above procedure is that while the engine cranks it consumes whatever fuel vapor is stuck in there. Once it starts running then the fuel pump will feed it fuel from the tanks.
 
alfadog said:
Try this. Throttle & mix full forward, hit the fuel pump switch, watch the fuel pressure gauge. When the needle stabilizes at its pressure easy count of 3 (longer if cold) and switch off. Pull the mixture back to lean, throttle open an inch and start cranking, when it chugs bring the mixture in and bring the throttle to 900-1000 rpm until clear and solid then lean back hard and idle down to as low as it will run smooth.
Click to expand...

That is the procedure I use to cold start. I am pretty sure that will flood the engine badly if you try it hot.
Click to expand...

Ditto.

I'd add that often nothing works for me in the winter. It's just fussy in cold weather.

Also, this engine's fuel-injection woes often cause me to crank the starter so many times in my fruitless efforts to get it started that the battery loses its charge. The Arrow is just an unpleasant plane to start.
 
NoHeat said:
Ditto.

I'd add that often nothing works for me in the winter. It's just fussy in cold weather.

Also, this engine's fuel-injection woes often cause me to crank the starter so many times in my fruitless efforts to get it started that the battery loses its charge. The Arrow is just an unpleasant plane to start.
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Most of the time in Arrows when people think they are 'flooded' on a hot start, they don't even have liquid fuel in the engine yet and grind the starter down getting fuel up to the injector nozzles.

With a hot engine, you can go ahead and flood it for real, all you want, it won't take more than a few seconds for any fuel in the cylinder to boil off into vapor. Then as soon as it pulls enough air in to get the mix to UEL it'll fire right off. Next time you hot start the engine go ahead full throttle full mix pump on needle tops out count 1,2,3,4,5,6, pump off, master off, mixture in lean idle position and wait 25 seconds, master on, hand on throttle start cranking and be ready to pull the throttle back in 4 blades when it catches.
 
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With the arrows I flew in, I would hot start as follows.

Throttle and mixture closed.
Fuel pump on.
Run the pump 30 seconds.

Throttle to starting position/cracked.
Bump mixture momentarily to prime.

Ignition.

Worked like a charm. As it catches, advance mixture.

The extended fuel pump run clears hot fuel from the heat soaked manifold/tubing, and cools the fuel system components. When priming, it's cool fuel being used instead of vapor.
 
cirrusmx said:
The logic behind the above procedure is that while the engine cranks it consumes whatever fuel vapor is stuck in there. Once it starts running then the fuel pump will feed it fuel from the tanks.
Click to expand...


I've found that attempting to start with the mixture anywhere other than ICO is not going to work.

With fresh mags and a well tuned fuel system our arrow is one of the easy planes to start in our fleet.
 
Skylane81E said:
I've found that attempting to start with the mixture anywhere other than ICO is not going to work.

With fresh mags and a well tuned fuel system our arrow is one of the easy planes to start in our fleet.
Click to expand...

Mine starts easily every time from ICO, hot or cold. The only difference being prime it with the fuel pump and mixture control when cold.
 
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