akschu

My Feedback: (5)

Ok, I called Mr cline and he said that you want to run the engine at peak and not 300rpm rich when the regulator is 1" away from the carb. The reason makes perfect sense, the attitude of the plane and fuel level doesn't have any effect on the fuel air mixture because the fuel source is effectively only 1" away from the carb. When the plane is pointed up it's only drawing the fuel one inch which doesn't make enough difference to affect how it runs.

He also said that my idea of bending the tab down in the regulator to make it lean was a good one and i could go further. So after leaning the main to just barely peak rpm and with the tab bent down making the engine draw a little harder, the engine ran very strong and transitioned perfectly.

The resulting setup idled at 1600 rpm very well and seems to be real easy on fuel.

To all that helped sort this out: Thanks!

schu

PlaneKrazee

My Feedback: (14)

Great to hear you figured it out.

You'll love it.

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That great news.
Can I just ask, you where on earth did you get the idea that setting the top end minus 300 RPM rich would would be a good idea?

PlaneKrazee

My Feedback: (14)

bla bla,

That is how rich many people run a non regulated glow engine, including myself.

bla bla

Well, I've done this since the begining of the 70's and you learn something all the time.
can I ask... Why?
I richen my 4 strokes may be 1 click but never 2 strokes, they have such a broard "tuned" area that setting in the first 30% gives miles of cushion before a lean run.

PlaneKrazee

My Feedback: (14)

The engine leans to peak when you go vertical or near the end of the tank.

bla bla

Does it, mine you I only used pumped engines so maybe that makes a difference.
I presume this approach is becuase you're tuning with a tach?
Isn't that all abit over cautious?
I think the entire above thread senario is a superb example of learning to use your ear.
I don't mean that to sound pompous, I mean to start using your ear and setting the engine to what sound right, what works, what feels ringht and not necessarliyby the book. Sinarios change, weather, props...even pumps... the "book" is a generalisation, real life isn't.

PlaneKrazee

My Feedback: (14)

If you set the needle to peak on a non pumped engine the ground, take off and pull vertical it will go lean and maybe quit. I have seen it happen to others several times.

akschu

My Feedback: (5)

While I do use my ear and it works fine, the tach is more accurate. There are so many things that can make a non-pump engine run lean, I'll list a few here:

1. If you go vertical the carb needs to draw the fuel against gravity.
2. If the tank is almost empty then the pressure from the muffler is less effective because there is more compressable air in the tank.
3. The ram air effect on the carb can make some engines run a little leaner.

On a 3d ship this is even more important because you may be doing a hover so while it's running lean you are also not cooling the engine as well, and working it very hard. Tuning for 300 rpm will save your engine if it goes lean.

On my 4 stroke I found the sweet spot. If turn the needle in until the smoke goes away and it's running real clean (peaked) then add 2 clicks, then it's just right on a hover.

If you tied to run 2 strokes without making it a little rich on the ground and didn't have some castor in the fuel it would only be a matter of time before you destroyed the engine.

schu

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Well that amazing.
I've never backed off a 2 stroke (including decades with non pumped versions) even back in those heady, funfly days.
Just run the needle in until you hit the spot and bag, thats it. Sure it'll go lean if you drive past that spot but you'll hear that as soon as you lift the nose up.
I would never back an engine down to rich unless you expect to or want to, run a rich engine!
Mind you, I'm not one of those sicko's that spends his day hovering around... I'm a member of the elite, the distugsting...the truely perverted, that spend their days flying straight lines.