low cherokee 140 power

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ronthompson

Filing Flight Plan
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ron t
HAVE LOW POWER ON TAKEOFF 2200 RPMS AND INCREASES WHEN I PULL THE MIXTURE CONTROL AND I GET 200 MORE RPM'S....i WANT 2650 RPM'S .. CARB HEAT GETS 400 RPM LOSS WHEN PULLED ... WHAT IS GOING ON HERE...rt:nonod:

PRIMER IS CLOSED BUT COULD IT BE LEAKING OR DO i HAVE A COMPRESSION PROBLEM?
 
I wouldn't broadcast over the internet that I took off with a known deficiency. And I certainly wouldn't SHOUT it. :rolleyes:

I wonder if maybe it's a cable issue.
 
Have you checked for blockage in the muffler?
 
ronthompson said:
HAVE LOW POWER ON TAKEOFF 2200 RPMS AND INCREASES WHEN I PULL THE MIXTURE CONTROL AND I GET 200 MORE RPM'S....i WANT 2650 RPM'S .. CARB HEAT GETS 400 RPM LOSS WHEN PULLED ... WHAT IS GOING ON HERE...rt:nonod:

PRIMER IS CLOSED BUT COULD IT BE LEAKING OR DO i HAVE A COMPRESSION PROBLEM?
Click to expand...

A run to the mechanic may be embarrassing if you haven't worked through what every pilot should know about his airplane's performance.

For example....

In fall the air is colder, and therefore denser. You flew full rich all summer, now the mixture at full rich is too rich.

Unless you have a Constant Speed Prop on your PA28, you won't see 2650 on takeoff for long -- the RPMS will only increase as the airplane begins moving through the air.

Carb heat shouldn't cause a 400 RPM drop unless you have carb ice -- what were the conditions?
 
dmccormack said:
In fall the air is colder, and therefore denser. You flew full rich all summer, now the mixture at full rich is too rich.
Click to expand...


You must have posted this before your first cup of coffee this morning, Dan because you're thinking backwards.

Summertime = thin air = richer mixture
Wintertime = dense air = leaner mixutre
 
sounds like an exhaust leak or a carb. problem.. You might have to adjust the mixture screw on the carb as well
 
About 10 years ago the FBO at the airfield I was at had a Cherokee 140 with the exact same problem. One of the local mechanics declared the cam lobes were worn thus causing the problem and insisted on rebuilding the engine (the engine had 200 hours SMOH) After removing the engine, total overhaul and reinstalled, the same problem was there!

After further investigation by another mechanic it was discovered the muffler had a blockage. Muffler replaced and the problem went away.

Have someone pull the muffler and inspect.
 
Rotor&Wing said:
About 10 years ago the FBO at the airfield I was at had a Cherokee 140 with the exact same problem. One of the local mechanics declared the cam lobes were worn thus causing the problem and insisted on rebuilding the engine (the engine had 200 hours SMOH) After removing the engine, total overhaul and reinstalled, the same problem was there!

After further investigation by another mechanic it was discovered the muffler had a blockage. Muffler replaced and the problem went away.

Have someone pull the muffler and inspect.
Click to expand...

Piper mufflers were once famous for having their baffles come loose and plug the muffler's outlet.

But that shouldn't cause a 400 RPM drop with carb heat. That sounds like a collapsed heat hose. If it's rough, too, then the carb is probably flooding the engine. Maybe the float valve...

Dan
 
HI Dan.... ran into a pilot who use to flythe Cherokee 140 on trips and had the same problem with low power on take off.... I further examined the exhaust opening with him and see the baffling right up against the exhaust hole opening... backing up the pressure and having no power I,m told... WOW.... thanks again.... have mechanic look at it to fix and get me into the air again.....great site this Pilots of America website...wonder how much the fix will be.....? RT...thanks again...:eek::mad2:
 
Check for a blocked muffler because it's the path of least cost. If that checks out it's most likely the carburetor -and you can't adjust it! Charlie Melot Zephyr Aircraft Engines
 
the problem is probably that you have a cherokee 140.
 
Don't be dissin' the MIGHTY Cherokee 140... I have my first 50 hours in one, and I have a soft spot for them.
 
Learned to fly in a J3... Moved up to a BC12D Taylorcraft... The day I flew a Cherokee 140 (no dual instruction in those days, just get in, fire up, go) I felt like I was in an Indy Car - Oh man the power, and those cool rudder pedals, and the inside wasn't all worn and tattered, it was heaven...... I still have a warm spot for these birds - though they now look and sound like my old T-craft...

denny-o
 
flyingcheesehead said:
I was gonna say... Isn't "low cherokee 140 power" redundant? ;) :rofl:
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HEY!

It'll carry more and fly faster than the Cessna 150 (insert bumper
sticker).

btw - isn't the point of flying to, well, fly? At least for me, I'm more
interested in the flying than the destination.

(owner of a '74 Cherokee 140)
 
Bob Noel said:
HEY!

It'll carry more and fly faster than the Cessna 150 (insert bumper
sticker).

btw - isn't the point of flying to, well, fly? At least for me, I'm more
interested in the flying than the destination.

(owner of a '74 Cherokee 140)
Click to expand...

Yep, and climb significantly better than a 150 as well.


Trapper John
 
Bob Noel said:
HEY!

It'll carry more and fly faster than the Cessna 150 (insert bumper
sticker).

btw - isn't the point of flying to, well, fly? At least for me, I'm more
interested in the flying than the destination.
Click to expand...

Oh, I love Cherokees, and given $20K or so I'd buy a Cherokee 140 over a 152 in a heartbeat - But they're still underpowered, and we still give 'em crap, because we love 'em anyway. :yes:
 
Well It wouldn't be so underpowered if you dropped a hundred pounds :D:D
 
flyingcheesehead said:
Oh, I love Cherokees, and given $20K or so I'd buy a Cherokee 140 over a 152 in a heartbeat - But they're still underpowered, and we still give 'em crap, because we love 'em anyway. :yes:
Click to expand...

I'd say the 140 is more limited wrt useful load than power. I've upgraded
to 160hp (and re-pitched the prop), but I still only have a max gross
of 2150 lbs.
 
Bob Noel said:
I'd say the 140 is more limited wrt useful load than power. I've upgraded
to 160hp (and re-pitched the prop), but I still only have a max gross
of 2150 lbs.
Click to expand...

Maybe so, but I can fit in one. In a 150, my knees are on the bottom of the yoke. I can't fly it at all. :no: 152 ain't much better - I rode in one once, but I wouldn't fly one or ride in one again.
 
Anyone know onthe web where i can look at a breakdown of the cherokee 140 muffler system...Rt
 
I learned what underpowered really is yesterday....

Temps about 74 F, winds calm, 5000' runway.

I landed and was set to takeoff from about the 2000' mark (still learning to land this taildragger on pavement -- and by the time I was airborne, the pavement was wet).

I pushed in full power, started rolling... seemed to take forever to get to tail-up speed.

:jeopardy theme song:

Tail's up, now at flying speed, the ground sorta falls away. Wow those trees are close...

Hmm..what's this?

Oh. carb heat.

Vroom.

That's more like it!

I'm guessing I took off with a little less than 45 HP. :eek:
 
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