Engine died on runway

cowman

cowman

Final Approach
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Cowman
So this happened today... temperatures were right around 5F. The airplane, a PA-28-181 fresh out of annual, had been sitting in a heated hangar all night. Got it running, taxied down slowly(icy taxiway), went through a runup with everything seeming to be normal.

Got my takeoff clearance, pulled out on the runway and shoved the throttle forward and it just sputtered and died. I informed the tower of the situation and tried a restart... started easily. I taxied back to the ramp and had a mechanic check it... he ran it up several times and looked under the cowl... no problems found.

Theories were either it was cold and opening the throttle too fast "choked it out" or carb ice.

A CFI was around and hopped in, again we ran it up with no problems. Took it through the pattern.... no problems.

After earlier delays and all the monkeying around it was late and wind was starting to get less than favorable so I ended up calling it a day.

Anyway, any thoughts on the two theories and how to avoid? Perhaps taxi out with the carb heat on?
 
Check the muffler for loose internals. Had the same thing happen with a 1971 Cherokee 140 intermittently. A loose piece inside the muffler would occasionally partially block the muffler outlet. People tend to just check the muffler for external leaks.
 
Probably pretty cold for carb ice, sounds like you might have been aggressive going full throttle or left the carb heat on?
 
Carb heat was off, mixture full rich.

Field elevation is just under 1000'
 
cowman said:
Carb heat was off, mixture full rich.

Field elevation is just under 1000'
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The Accelerator pump is set too lean for cold weather ops. and will not provide enough fuel for the idle to cruise transition during the cold weather.

That setting can be changed by setting the pump linkage to a longer pump stroke.
 
Tom-D said:
The Accelerator pump is set too lean for cold weather ops. and will not provide enough fuel for the idle to cruise transition during the cold weather.

That setting can be changed by setting the pump linkage to a longer pump stroke.
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That is the first answer I heard all day that makes perfect sense to me.

Now, it's probably not likely I'll be flying in these temperatures much but no doubt some. Could I get away with turning the carb heat on immediately after startup, taxing out with it on and then turning it back off before takeoff + applying power slowly to 1700-2000RPM or so with the brakes on before going to full power for takeoff?

I'd hate to have to hunt down an A&P every time the temperature changes or I fly south.
 
If you use mostly auto fuel, your carb may be allowing liquid fuel to run down and pool in the carb heat box. When you hit the power, that pooled fuel could be sucked into the engine, flooding it out It happened to me recently on a Continental C-85 (your Lycoming shouldn't be as susceptible) although I'd think a normal run up would clear the heat box of pooled fuel.

A key thing is - did it stave out -or flood out?
 
nrpetersen said:
If you use mostly auto fuel, your carb may be allowing liquid fuel to run down and pool in the carb heat box. When you hit the power, that pooled fuel could be sucked into the engine, flooding it out It happened to me recently on a Continental C-85 (your Lycoming shouldn't be as susceptible) although I'd think a normal run up would clear the heat box of pooled fuel.

A key thing is - did it stave out -or flood out?
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If it flooded out, it would have not died, it would have caught as it used up the extra fuel. or he would not have gotten it started again easily.

simply advance the throttle slowly, it will be OK. lots of old Tillison carbs flying with out any accelerator pumps. slam the throttle open and they all die.
 
The fuel doesn't vaporize well in cold weather. Some of it will often puddle in the intake runners on Lycomings at idle and when the throttle is opened quickly, it gets sucked in and can flood the engine and kill it. We had a Citabria with an O-320-A2D that was bad for that. You could see the black smoke and hear the hesitation as the pilot opened the throttle. Another Citabria, with an O-235K2C, quit in the overshoot of a practice forced approach on a cold day; they landed in the field and we dragged them out to a road and they took off.

The solution is to treat the throttle carefully, like Tom says. Give the engine time to think.

Dan
 
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You stated you shoved the throttle forward. Don't shove, count to 5.
 
I was trying to think up an idea that was not operator error - but yeah, don't shove anything when its cold . . .
 
Dan Thomas said:
The fuel doesn't vaporize well in cold weather. Some of it will often puddle in the intake runners on Lycomings at idle and when the throttle is opened quickly
Dan
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That is why you never prime any engine that is not cranking.
 
comanchepilot said:
I was trying to think up an idea that was not operator error - but yeah, don't shove anything when its cold . . .
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That's what she said.


(sorry, I had to)




I thought I pushed it forward at a fairly normal speed but it died so perhaps that was too much.
 
cowman said:
I thought I pushed it forward at a fairly normal speed but it died so perhaps that was too much.
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It really doesn't hurt to leave the carb heat on from start up to take off, the warmer that carb is, the better off you are.

There are occasions in extreme cold that you must leave the hot air on, or the mixture will go too lean. About -15 is where that problem starts. the cruise jet isn't large enough to get a rich mixture with air that dense.
 
cowman said:
Could I get away with turning the carb heat on immediately after startup, taxing out with it on and then turning it back off before takeoff + applying power slowly to 1700-2000RPM or so with the brakes on before going to full power for takeoff?
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Unrelated and a bad idea. When using carb heat you're running unfiltered air into the engine. Not a good idea on the ground.
 
LDJones said:
Unrelated and a bad idea. When using carb heat you're running unfiltered air into the engine. Not a good idea on the ground.
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It's better than having your engine quit. OBTW, how much dirt is in the air you breath? if it is bad enough to harm your engine, should you be breathing it ?

When you have really cold temps, things are froze up, snow on the ground, how much dirt will be in the air?

Use that heat, it was put there for a reason.
 
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Tom-D said:
It's better than having your engine quit. OBTW, how much dirt is in the air you breath? if it is bad enough to harm your engine, should you be breathing it ?
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So we don't need air filters? That'll be a savings.
 
If there is the slightest possibility of carb ice, keep the carb heat all the way out. Don't push it back in until the throttle is full and you are starting down the runway on your take off roll.
 
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LDJones said:
So we don't need air filters? That'll be a savings.
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There ya go, believing I said we didn't need filters. When in actually you have a theory that does not exist in reality, when the Temps are low, ground is frozen, and covered with snow.
 
cowman said:
That is the first answer I heard all day that makes perfect sense to me.

Now, it's probably not likely I'll be flying in these temperatures much but no doubt some. Could I get away with turning the carb heat on immediately after startup, taxing out with it on and then turning it back off before takeoff + applying power slowly to 1700-2000RPM or so with the brakes on before going to full power for takeoff?

I'd hate to have to hunt down an A&P every time the temperature changes or I fly south.
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You can prevent the problem by slowing down the rate of throttle advance without changing anything.
 
If this was a Cessna 150/172 or a Maule I'd say, "did you check the primer knob". Seems like I recall exactly that behavior if one didn't close and lock the primer. Have no idea whether that has any traction on a Piper.
 
Bill Watson said:
If this was a Cessna 150/172 or a Maule I'd say, "did you check the primer knob". Seems like I recall exactly that behavior if one didn't close and lock the primer. Have no idea whether that has any traction on a Piper.
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On a piper it will cause the engine to run lean as well, lean enough to not run well, if at all.
 
ja_user said:
On a piper it will cause the engine to run lean as well, lean enough to not run well, if at all.
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It will make it rich. There's a spring-loaded needle inside the primer that closes off the primer's outlet to the engine. Locking the primer forces that needle into the hole. If it's unlocked it can let the engine suck extra fuel through the primer system, especially at low manifold pressures (low throttle settings).

Dan
 
I always advance the throttle slowly, use the checklist faithfully. That way primer,and mixture are set for takeoff.
 
ja_user said:
On a piper it will cause the engine to run lean as well, lean enough to not run well, if at all.
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Just the opposite, but only when the boost pump is on. except in a J-series
 
Henning said:
You can prevent the problem by slowing down the rate of throttle advance without changing anything.
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Won't work in the older carbs, the cruise jet simply isn't large enough to provide enough fuel to run in real cold air.
 
Tom-D said:
Won't work in the older carbs, the cruise jet simply isn't large enough to provide enough fuel to run in real cold air.
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He has an Archer, that's got as modern of a carb on it as they come on aircraft. Considering it was a one off problem, very likely the problem was opening the throttle to fast before the engine was sufficiently warm.
 
Henning said:
He has an Archer, that's got as modern of a carb on it as they come on aircraft. Considering it was a one off problem, very likely the problem was opening the throttle to fast before the engine was sufficiently warm.
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He has a Marvel MA3-SPA they date back to the1930s.

If that carb was reworked, it could be jetted lean and probably needs the accelerator pump linkage set to a longer stroke to provide more fuel for the transition period.

slowing the throttle stroke, won't have much effect on the amount of fuel delivered while opening the throttle plate.
 
Dan Thomas said:
It will make it rich. There's a spring-loaded needle inside the primer that closes off the primer's outlet to the engine. Locking the primer forces that needle into the hole. If it's unlocked it can let the engine suck extra fuel through the primer system, especially at low manifold pressures (low throttle settings).

Dan
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That's what it does in the Maule and the Cessnas as I recall. So rich that the engine will stumble or quit.
 
Not enough pilots have driven an old carbureted car. Sigh.

Try romping the gas pedal in one if you ever get the chance.
 
Tom-D said:
Just the opposite, but only when the boost pump is on. except in a J-series
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Even with the boost pump off as a renter discovered on a Warrior. It spit and stumbled the whole way down final when the manifold pressure was low enough to suck in fuel it couldn't burn.
 
Bill Watson said:
That's what it does in the Maule and the Cessnas as I recall. So rich that the engine will stumble or quit.
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Yep! If the engine runs rough below about 1500 RPM the first thing I tell my student to check is the primer. The Maule primer has a BAD habit of looking locked when its really not. So I teach my students to pull on it to make sure it doesn't move.

I agree on slamming the throttle full forward. If you do it quick enough in our Maules you get a dead engine. I had a student yesterday firewall it during a engine out and about killed the engine above the pasture. :hairraise:

They also don't like the cold very much. Right now even with the OAT around 40*F the oil temp never gets above 100*F and the head temp never gets much above 200-250*F So starting them even after a quick turn around is a B****.
 
Like others have said, nice and smooth on the power during takeoff. It's not a turbine or FADEC engine, you can't just slam it up to full power.

That's my guess
 
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