I'm having a hard time getting the arrow started when I follow the method in the POH (mixture idle cutoff then advance when it fires). It seems like it cranks a little sluggish maybe, and it seems to start easier when I just leave the mixture full rich, which isn't the manufacturer recommended method as far as I know. Any particular reason this could be? Bad starter or weak battery?
Trouble starting Arrow
- Thread starter JordanD
- Start date
Roger Roger
Bottom of the list
On the failure to catch, maybe weak spark? Not sure. Never had that exact problem, usually starting troubles on the injected Lycs are the opposite...people flood em by priming when they don't need it.
Oh also 9 times out of 10 a slow starter is not the starter... Battery sometimes, bad connections often, corroded wiring sometimes.
Oh also 9 times out of 10 a slow starter is not the starter... Battery sometimes, bad connections often, corroded wiring sometimes.
Ironically the day I posted this it started right up. It seems like following the checklist to a t was causing it to flood sometimes. The checklist also calls for having the fuel pump on during the whole start (beyond priming). Is this necessary for a fuel injected engine?
MidlifeFlyer
Well-Known Member
Depends. Some call for it some don't. And at some times one way may work better with the same airplane than another.
One item that I see causing a problem from time to time is being slow. What I mean is, whether carbureted or fuel injected, I've seen pilots prime the engine and then sit around having a cup of coffee (figuratively speaking), reading the next step in the checklist, before turning the key. I think the better approach is to think of prime-through start as a mini-sequence that should be briefed before prime and then done without having to look at the checklist again. You know, sort of like takeoff to en route climb (at least I hope people don't roll down the runway looking at the checklist to figure out what speed to rotate at).
Probably not you, but a big pause between turning on the fuel pump for priming and start would certainly account for flooding.
Of course, a sluggish starter is always suspect.
One item that I see causing a problem from time to time is being slow. What I mean is, whether carbureted or fuel injected, I've seen pilots prime the engine and then sit around having a cup of coffee (figuratively speaking), reading the next step in the checklist, before turning the key. I think the better approach is to think of prime-through start as a mini-sequence that should be briefed before prime and then done without having to look at the checklist again. You know, sort of like takeoff to en route climb (at least I hope people don't roll down the runway looking at the checklist to figure out what speed to rotate at).
Probably not you, but a big pause between turning on the fuel pump for priming and start would certainly account for flooding.
Of course, a sluggish starter is always suspect.
Roger Roger
Bottom of the list
Not typically...what motor is in there? Lycoming or Continental?
Lycoming IO-360-C1C I believe
Roger Roger
Bottom of the list
OK. I have never left the fuel pump on while starting a Lycoming injected engine, except in one specific airplane with one specific engine, only when the engine had just been run and the OAT was over about 60. (for whatever reason that particular bird heat soaked the fuel pump when sitting and would vaporize the fuel there...so the engine would start then die out from lack of fuel).
I'm surprised that that is on the checklist for the Arrow.
Roger Roger
Bottom of the list
I, uh, think they mean the alternate static (little sump style valve by your left knee, at least if it's built like a Cherokee 6)
Hammertime
Well-Known Member
A lot of separate questions and issues here. "Problems starting" can mean a lot. If it's a slow and rapidly deteriorationg cranking speed, it could be a bad battery and/or corroded cables (one of the most common causes for slow cranking is a corroded ground wire). If it's a slow, but consistent cranking speed, that could be a worn starter, or merely a different brand of starter. (The flight school I used to work at changed starter brands for a massive improvement in cranking speed and ease of start.) If it's difficulty getting the engine to catch, well, welcome to the fuel injection club... Just looking at some of the procedural questions that have come up, I'll see if I can't muddy the waters up a bit (disclaimer: while I am very familiar with the IO-360, I am not familiar with the Arrow). In no particular order...
The reason they have the fuel pump on for the start is unrelated to priming. It's actually because the Arrow is a low wing aircraft. Basically, you need the electric pump to push the fuel to the engine until the engine driven pump is being driven fast enough to maintain fuel pressure. Related starting tip: When priming the engine ensure that fuel pressure rises (or fuel flow is indicated). You should see approximately three seconds of priming after normal pressure/flow is indicated.
Some thoughts on priming. There's always a bit of a knack in knowing how much to prime an engine, as a lot depends on the temperature of the engine. It might seem counterintuitive, but immediately cranking after priming isn't necessarily the key. I've seen guys wait over a minute (on purpose) between priming and cranking on a cold day to allow the fuel more time to vaporize, with great success. However, I think most will agree with me that the most difficult starting situation is starting a hot fuel injected engine. As you well know, the engine and it's various components are air cooled, meaning that the air moving through the cowling convectively cools the engine by carrying the heat away. However, as soon as the engine is shut down on a hot day, the airflow ceases, and the engine heat soaks. All the heat that the engine block built up radiates into the other engine components such that they actually go up in temperature rather than cool off when the engine is shut down. (You're saying, "I know, get to the point already!") Of course, this heat rises, so that the components above the engine receive more heat than those below. So, next time you are preflighting, observre that the only engine component above block is the fuel distribution manifold, an aluminum disc about the size and shape of a hockey puck with small tubes (or fuel injector lines. Mechanics call the whole assembly "the spider") coming out of it. Anyway, the point of this texbook is that the spider gets really hot, and all the fuel in it vaporizes (this is not vapor lock). Practically speaking, this means that though the warm engine does not need priming, the fuel system does, and this is what's difficult about a hot start. When priming, you need to get enough fuel up the the fuel injector lines to get an indication off of the fuel flow gauge, without actually priming the engine.
Procedure-wise, if I was having difficulty hot starting a fuel injected engine, I usually found it easier (after a couple of failed attempts) to purposefully flood the engine, and use the flooded start procedure. IDK what the Arrow POH says, but basically you are starting with too much fuel, and trying to get the air/fuel mixture right so the engine will fire. So...
1. Prime the piss out of it. (This will also cool the fuel injector lines and maniflold.)
2. Set mixture to idle cutoff, and throttle to idle.
3. Start cranking, and at the same time, slowly advance the throttle, allowing more and more air into the enigine until it catches.
4. Quickly put the mixture to rich, and bring the throttle back to idle before the whole ramp starts wondering what kind of idiot starts his engine at wide open throttle.
An aside on the alternate air... Who knows what kind of awesome formatting/editing errors Piper has in their manual, but I'm sure they want you to check both the alternate air lever (for freedom of movement), and the alternate static source (VSI bump).
Wow. Where's my pulitzer?
The reason they have the fuel pump on for the start is unrelated to priming. It's actually because the Arrow is a low wing aircraft. Basically, you need the electric pump to push the fuel to the engine until the engine driven pump is being driven fast enough to maintain fuel pressure. Related starting tip: When priming the engine ensure that fuel pressure rises (or fuel flow is indicated). You should see approximately three seconds of priming after normal pressure/flow is indicated.
Some thoughts on priming. There's always a bit of a knack in knowing how much to prime an engine, as a lot depends on the temperature of the engine. It might seem counterintuitive, but immediately cranking after priming isn't necessarily the key. I've seen guys wait over a minute (on purpose) between priming and cranking on a cold day to allow the fuel more time to vaporize, with great success. However, I think most will agree with me that the most difficult starting situation is starting a hot fuel injected engine. As you well know, the engine and it's various components are air cooled, meaning that the air moving through the cowling convectively cools the engine by carrying the heat away. However, as soon as the engine is shut down on a hot day, the airflow ceases, and the engine heat soaks. All the heat that the engine block built up radiates into the other engine components such that they actually go up in temperature rather than cool off when the engine is shut down. (You're saying, "I know, get to the point already!") Of course, this heat rises, so that the components above the engine receive more heat than those below. So, next time you are preflighting, observre that the only engine component above block is the fuel distribution manifold, an aluminum disc about the size and shape of a hockey puck with small tubes (or fuel injector lines. Mechanics call the whole assembly "the spider") coming out of it. Anyway, the point of this texbook is that the spider gets really hot, and all the fuel in it vaporizes (this is not vapor lock). Practically speaking, this means that though the warm engine does not need priming, the fuel system does, and this is what's difficult about a hot start. When priming, you need to get enough fuel up the the fuel injector lines to get an indication off of the fuel flow gauge, without actually priming the engine.
Procedure-wise, if I was having difficulty hot starting a fuel injected engine, I usually found it easier (after a couple of failed attempts) to purposefully flood the engine, and use the flooded start procedure. IDK what the Arrow POH says, but basically you are starting with too much fuel, and trying to get the air/fuel mixture right so the engine will fire. So...
1. Prime the piss out of it. (This will also cool the fuel injector lines and maniflold.)
2. Set mixture to idle cutoff, and throttle to idle.
3. Start cranking, and at the same time, slowly advance the throttle, allowing more and more air into the enigine until it catches.
4. Quickly put the mixture to rich, and bring the throttle back to idle before the whole ramp starts wondering what kind of idiot starts his engine at wide open throttle.
An aside on the alternate air... Who knows what kind of awesome formatting/editing errors Piper has in their manual, but I'm sure they want you to check both the alternate air lever (for freedom of movement), and the alternate static source (VSI bump).
Wow. Where's my pulitzer?
Roger Roger
Bottom of the list
500 hours ish and well over 1000 cycles in injected big bore Lycomings doing quick turns all day long, and by far the best procedure I've found for hot starting them is to just crank with the throttle cracked and mixture cutoff. As soon as it fires, go mixture half rich and boom, you're up and running. I've not tried this above about 75* F since that's as warm as it gets up here, but at those temperatures and below that technique works probably 90%+ of the time
trafficinsight
Well-Known Member
Agreed, 400ish hours in 206H's and I've never had trouble starting them even hot and in hot/humid weather.
I would say that if the engine wont start in idle cutoff but will start with the mixture rich you're not priming enough. I do the following with a room termperature engine for Lycoming engines:
1.) Master on
2.) Mags on Both
3.) Mixture rich
4.) Throttle cracked
5.) Fuel pump on
6.) Watch for movement on the fuel flow gauge, if none advance the throttle slightly
7.) Count 5 mississippis at a 1/2 1812 overture pace
(meaning count to 5 slowly)8.) Fuel pump off
9.) Mixture ICO
10.) Crank (10 second duty cycle with 20 seconds in between if you need it. After three tries you have to wait many minutes, give a hoot: don't pollute the ramp with your starter parts)
11.) As soon as the engine catches advance the mixture.
12.) Look like a pro
With a hot engine I just skip the priming steps. In warm weather you can prime and start in pretty quick succession, in cold weather wait 15 to 20 seconds after priming to allow some of the fuel to vaporize. (fuel doesn't burn, fuel vapor does)
fholbert
Mod's - Please don't edit my posts!
Autothrust Blue
”…trusting ze process…”
Priming "just enough." This procedure works great on said 206, and you'll impress everyone around with your hot start prowess.Agreed, 400ish hours in 206H's and I've never had trouble starting them even hot and in hot/humid weather.
I would say that if the engine wont start in idle cutoff but will start with the mixture rich you're not priming enough. I do the following with a room termperature engine for Lycoming engines:
1.) Master on
2.) Mags on Both
3.) Mixture rich
4.) Throttle cracked
5.) Fuel pump on
6.) Watch for movement on the fuel flow gauge, if none advance the throttle slightly
7.) Count 5 mississippis at a 1/2 1812 overture pace
8.) Fuel pump off
9.) Mixture ICO
10.) Crank (10 second duty cycle with 20 seconds in between if you need it. After three tries you have to wait many minutes, give a hoot: don't pollute the ramp with your starter parts)
11.) As soon as the engine catches advance the mixture.
12.) Look like a pro
With a hot engine I just skip the priming steps. In warm weather you can prime and start in pretty quick succession, in cold weather wait 15 to 20 seconds after priming to allow some of the fuel to vaporize. (fuel doesn't burn, fuel vapor does)
Had a guy at our field get out and kick the cowling occasionally when he couldn't get it started. Always seemed to fire right up for him when he got back in. I'd say give that a try.
Edit: It was a Cirrus. Not sure if this procedure applies to the arrow.