what is the ideal egt for a cessna 150 in cruise

[earl72]

im having a egt gauge put in my toy so i can lean it properly just wondering if anyone knows what the temp is for a 0-200

 

[dell30rb]

Well you gotta decide if you're running rich or lean of peak temp. You'll pick a certain number of degrees on the rich side or lean side of peak. Peak temp will vary with altitude and throttle setting.

 

[earl72]

im planning on running rich of peak

 

[poadeleted20]

In an O-200, the ideal EGT for cruise is the one you get when you lean until the first sign of roughness and then enrich until it smooths out again.

 

[Skip Miller]

im having a egt gauge put in my toy so i can lean it properly just wondering if anyone knows what the temp is for a 0-200

Nobody has answered your question with an ideal temperature. That is because the temperature will vary from flight to flight based on , throttle setting, and other factors too..

The gauge you are installing most likely has hash marks on its face for each 25* but the hash marks are not labeled with a temperature. These gauges allow you to identify the peak temperature and then lean or enrich the mixture x degrees rich or lean of that peak as your preference dictates.

Ron Levy in the message above has it right. In summary: lean to rough, rich to smooth.

-Skip

 

[jesse]

In an O-200, the ideal EGT for cruise is the one you get when you lean until the first sign of roughness and then enrich until it smooths out again.

What Ron says.

If you want to cover the usage of the EGT gauge (which to be honest isn't that useful in your 150) and leaning in general I'm available any time

 

[MSPAviator]

In an O-200, the ideal EGT for cruise is the one you get when you lean until the first sign of roughness and then enrich until it smooths out again.

That's how I do it in the O-235 as well. I find that the engine can be leaned to the point where it sounds like it is running smoothly, but slowly riching the mixture knob can yield some more RPM.

The 152 I flew only had this EGT needle that swung vaguely towards the cold or hot end, there weren't any actual temperature markings.

I also lean aggressively for taxi, I pull the mixture far enough back so the engine will sputter and die if I advance the throttle over 1500 RPM or so, which is probably plenty for taxiing.

 

[earl72]

i think i will take you up on that jessie i just fixed my 150 again because of a fouled plug

 

[Tom-D]

In an O-200, the ideal EGT for cruise is the one you get when you lean until the first sign of roughness and then enrich until it smooths out again.

And then trim it to level flight, and pull one more click on the mixture, and watch the VSI, if it goes up, Pull one more click, retrim, and pull one more click, if it goes up again, do one more cycle.

If it goes down, push it in two clicks.

you can usually get it to run very smooth at about 50-75 degrees lean of peek. and at 2400 RPM that will get you about 4.5 to 5.0 GPH

with the average tach, and indicator installed I've never seen 2 engines run and indicate the same.

As you pointed out it really is a seat of the pants thing. but you can tweak it using the VSI.

 

[Tom-D]

i think i will take you up on that jessie i just fixed my 150 again because of a fouled plug

Which Carb do you have on the 0-200 now?

the old black label? with a "V" & "MF" stamped on the tag, or the new kelly rebuilt?

 

[earl72]

i will have to check (the next time i have the cowling off) i know it was rebuilt 3 years ago

 

[Tom-D]

i will have to check (the next time i have the cowling off) i know it was rebuilt 3 years ago

That is why you are fouling plugs. Keep your eye out for an old black label carb with a 2 piece venturi, and metal floats, they do not run rich as the new carbs that have plastic floats and single piece ventures.

Never have a 0-200 carb overhauled, it only has three main moving parts. and the new updated carbs are a POS.

 

[poadeleted20]

That's how I do it in the O-235 as well. I find that the engine can be leaned to the point where it sounds like it is running smoothly, but slowly riching the mixture knob can yield some more RPM.

That's right. Using the "lean to rough, enrich to smooth" method will set you right about peak EGT, which is a bit lean of peak power, and is probably the best balance of power and economy for cruise. Best economy is a tad lean of peak but will have some roughness to it due to the inherent unevenness in fuel/air mix distribution among the cylinders in a carbureted engine. If you are leaning for peak power for high-altitude takeoff or climb above 5000 DA with a fixed pitch prop (and there aren't too many c/s props on O-235 engines), lean to peak RPM, which will be a bit rich of that best cruise EGT described above.

I also lean aggressively for taxi, I pull the mixture far enough back so the engine will sputter and die if I advance the throttle over 1500 RPM or so, which is probably plenty for taxiing.

That's a good practice if you want to avoid lead fouling.

 

[poadeleted20]

And then trim it to level flight, and pull one more click on the mixture, and watch the VSI, if it goes up, Pull one more click, retrim, and pull one more click, if it goes up again, do one more cycle.

When you've leaned as I suggested, you should have to enrich to make the RPM go up and increase power. Further leaning should cause a drop in RPM, i.e., a decrease in power, and cause the airplane to slow and/or descend. If you can get more power out of the engine (required to cause it to climb after trimming for level) by leaning the mixture after adjusting the mixture as described (lean to rough, enrich to smooth), your carb or something else needs adjusting, since the engine should still be smooth at a point well lean of best power.

 

[p1l0t]

Like these guys said, lean till it gets rough and smooth it out. It will vary depending on conditions. (But I'll play Devil's advocate here and tell you that about 1300-1350F seems pretty common to me on many lycomings)

<---<^>--->

 

[poadeleted20]

Like these guys said, lean till it gets rough and smooth it out. It will vary depending on conditions. (But I'll play Devil's advocate here and tell you that about 1300-1350F seems pretty common to me on many lycomings)

My experience with Lycomings with full engine analyzers is that 1450F or higher is more what you see at peak EGT (which is about what you get with the "lean by ear" method), and 1300-1350F is closer to full rich/full throttle at SL (typically about 1250-1325F), but that number is very sensitive to installation, so EGT's should be viewed more as relative numbers than absolute values. In any event, the OP's O-200 engine is a Continental.

 

[Tom-D]

When you've leaned as I suggested, you should have to enrich to make the RPM go up and increase power. Further leaning should cause a drop in RPM, i.e., a decrease in power, and cause the airplane to slow and/or descend. If you can get more power out of the engine (required to cause it to climb after trimming for level) by leaning the mixture after adjusting the mixture as described (lean to rough, enrich to smooth), your carb or something else needs adjusting, since the engine should still be smooth at a point well lean of best power.

No, it simply means your didn't get it right with the first grab and pull.

I was not disagreeing with you, simply adding a step after you are steady at cruise altitude, simply tweak the mixture and you will find that it will still be a tiny bit rich. and the VSI is your best indicator to tell you that.

If 1 more click on the mixture makes you descend, then you were right on the money, if it makes you climb, then you were richer than you should be. wait a little while and try 1 more click see what happens.

OBTW, you can run best power at any throttle setting in the 0-200 and not harm the engine.

I run the 0-200/150 at 2450 RPM leaned to best power, and that is what you get when you lean as you described, simply because the 1 click of the mixture cable will take you from best power to lean misfire.

Remember we are talking about a Marvel Shibler (sp) carb mounted on a remote spider and 4 equal length induction tubes, Un like the 0-235 the 0-200 will indicate with in 20 degrees of all cylinders on my calibrated test cell.

 

[poadeleted20]

No, it simply means your didn't get it right with the first grab and pull.

Well, if you lean one click after doing what I suggested and the plane climbs, you definitely went way too far rich after leaning to rough, because you've gone past best cruise and past best power to more than 100F rich of peak. If that happens, either you have an engine problem because fuel isn't being distributed evenly, or you need is an ear exam because you're not hearing what the engine is doing.

I was not disagreeing with you, simply adding a step after you are steady at cruise altitude, simply tweak the mixture and you will find that it will still be a tiny bit rich. and the VSI is your best indicator to tell you that.

If it's only "a tiny bit rich," you'll still be lean of peak power, and pulling it out will put you leaner, with less power, and the plane will descend.

OBTW, you can run best power at any throttle setting in the 0-200 and not harm the engine.

I know you can't do that above 75% power below 5000 DA with a Lycoming with that assurance, and I'm reasonably sure the same is true of a C-150. If memory serves, the C-150 book says not to lean at full throttle below 5000. However, at/below 75% power (i.e., "normal" cruise), you're probably right.

I run the 0-200/150 at 2450 RPM leaned to best power, and that is what you get when you lean as I described.

That all depends on DA and what prop you have.

 

[Tom-D]

My experience with Lycomings with full engine analyzers is that 1450F or higher is more what you see at peak EGT (which is about what you get with the "lean by ear" method), and 1300-1350F is closer to full rich/full throttle at SL (typically about 1250-1325F), but that number is very sensitive to installation, so EGT's should be viewed more as relative numbers than absolute values. In any event, the OP's O-200 engine is a Continental.

The thing to remember here is the accuracy of the gauge system is solely dependent upon the installation of the probes. they must be installed exactly the same distance from the exhaust seat as possible to get a comparison reading. I've seen a variation of as much as an inch on the same engine, and of course the readings are all over the scale in those installations.

Ron you can take the exact same engine, and the exact same gauge and move the probes up or down and make those reading any thing you like.

 

[Tom-D]

Well, if you lean one click after doing what I suggested and the plane climbs, you definitely went way too far rich after leaning to rough, because you've gone past best cruise and past best power to more than 100F rich of peak. If that happens, either you have an engine problem because fuel isn't being distributed evenly, or you need is an ear exam because you're not hearing what the engine is doing.

No Ron, most pilots will not get it right on the first pull, they either push it back in too far. or thing the loss of power is normal.

If it's only "a tiny bit rich," you'll still be lean of peak power, and pulling it out will put you leaner, with less power, and the plane will descend.

True, that is what I have tried to say.

I know you can't do that above 75% power below 5000 DA with a Lycoming with that assurance, and I'm reasonably sure the same is true of a C-150. If memory serves, the C-150 book says not to lean at full throttle below 5000. However, at/below 75% power (i.e., "normal" cruise), you're probably right.




That all depends on DA and what prop you have.

This is one occasion that theory may be correct, but in practically the cruise and climb props are only 1 inch difference allowed on a 150. and remember the DA effects the MAP as well as the prop so they pretty much off set one an other.

 

[poadeleted20]

The thing to remember here is the accuracy of the gauge system is solely dependent upon the installation of the probes. they must be installed exactly the same distance from the exhaust seat as possible to get a comparison reading. I've seen a variation of as much as an inch on the same engine, and of course the readings are all over the scale in those installations.

Ron you can take the exact same engine, and the exact same gauge and move the probes up or down and make those reading any thing you like.

I think that's what I said.

 

[poadeleted20]

This is one occasion that theory may be correct, but in practically the cruise and climb props are only 1 inch difference allowed on a 150. and remember the DA effects the MAP as well as the prop so they pretty much off set one an other.

When you bury your responses in the quoted text, it's hard to respond to specific things you say. However, I suspect that as an instructor I've done a lot more flying with other pilots and observing their techniques and procedures, and not many of them are as incompetent as you suggest about executing the "lean to rough, enrich to smooth" technique once they've been taught it.

And changes in temperature without changes in pressure altitude do not change MP. PV=nRT only applies to a confined mass of gas.

 

[Tom-D]

" technique once they've been taught it.

That's the point, I see many owners that have no clue about mixture, they are the ones coming to me for maintenance. I think we see two different areas of the pilot population.

and on this page we probably have both.

 

[poadeleted20]

That's the point, I see many owners that have no clue about mixture, they are the ones coming to me for maintenance. I think we see two different areas of the pilot population.

Agreed, but once they've been taught it, they don't need the additional steps you suggest. The only value of those is to demonstrate what's happening as a result of mixture changes when training them to do it properly. After that, there's no need to fiddle further -- all that does is distract the pilot from more important tasks.

 

[Tom-D]

Agreed, but once they've been taught it, they don't need the additional steps you suggest. The only value of those is to demonstrate what's happening as a result of mixture changes when training them to do it properly. After that, there's no need to fiddle further -- all that does is distract the pilot from more important tasks.

It pays to recheck your mixture setting in the 150, and the VSI in flight is the better way. Simply try it, it will make you a believer.

we are talking about a mixture cable that moves the lever on the carb about 1/8th of an inch between each click. and they creep in flight. When I have the 150 trimmed correctly to hold altitude, and it starts to climb or descend some thing changed. most probably the mixture.

 

[Richard]

...I'm available any time

...for a nickle, for a dime, 15 cents for overtime.


Sorry, Jesse, I couldn't resist.

 

[GCA319]

An O-200 is probably the easiest engine to lean. Run it back until it's rough, then run it back in until it smooths out and there's best economy. Continue to run it in about 1/4" for best power. Atleast I think that's the procedure, it's been a few years since I've flown a 150 that didn't have an STCed engine (O-320, slightly different procedure).

 

[poadeleted20]

An O-200 is probably the easiest engine to lean. Run it back until it's rough, then run it back in until it smooths out and there's best economy. Continue to run it in about 1/4" for best power. Atleast I think that's the procedure,

That's pretty close. Your "best economy" is probably bit rich of true best economy, but provides a smoother run and a hair more power. For best power, you can't be sure in advance of the amount you'll have to push it in, but if you lean to peak RPM with that fixed pitch prop (lean until it rises, then drops, then enrich back to the highest RPM you saw), you're guaranteed best power (which by definition is highest RPM).

 

[Tom-D]

That's pretty close. Your "best economy" is probably bit rich of true best economy, but provides a smoother run and a hair more power. For best power, you can't be sure in advance of the amount you'll have to push it in, but if you lean to peak RPM with that fixed pitch prop (lean until it rises, then drops, then enrich back to the highest RPM you saw), you're guaranteed best power (which by definition is highest RPM).

Maybe if you had a vernier mixture cable you might (I say might) get it that close, but when you study the LOP graph and see how quickly the 0-200 goes from peak to lean misfire 1 or 2 clicks on the OEM mixture will get you beyond where you want to be.

That is why I say the VSI is a better indicator of performance than the Tach. you will see what the aircraft actually feels 1 click oneway or the other and you won't see it on the tach, but the aircraft will react.

 

[Tom-D]

Every 0-200 owner / operator should get the "tips on engine care" put out by Continental and read page 64 you'll see what I am talking about.

The second point I'd like to make on the subject of leaning the 0-200 in a 150 is that after you climb to altitude which is usually a few minutes running rich, it requires a few minutes to clean the combustion chambers, so the initial lean setting will change as this happens. That is why you should recheck your mixture setting and tweak it as necessary.