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Old 02-22-2015, 04:13 PM
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You can't fix STUPID
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As the rings seat the fuel load is too much. Some are noticeable. Some are not. Depends on how much blow by the ring had at initial tuning.
I heat load my motors for break in 10 times. Then it goes in the air.
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Old 02-22-2015, 04:19 PM
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Seven.Four Liters
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If you have 'blow-by' in a two stroke engine, where does it go?
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Old 02-22-2015, 07:15 PM
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Quote:
Originally Posted by N726AC View Post
If you have 'blow-by' in a two stroke engine, where does it go?
The same place it goes in a 4 stroke engine..... crankcase.
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Old 02-22-2015, 08:02 PM
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Seven.Four Liters
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Quote:
Originally Posted by flyin4fun View Post
The same place it goes in a 4 stroke engine..... crankcase.
Okay, now you're getting somewhere. In a four stroke, this blow by is either vented overboard or introduced back into the intake tract. Think about the pcv valve in an automobile.
Blow by in a two stoke is subject to a totally different fate.
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Old 02-22-2015, 09:33 PM
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Please. Tell us more.
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Old 02-22-2015, 10:34 PM
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This is watercraft oriented but offers an excellent explanation of two stroke (and four stroke) operation.

2 Stroke Engine vs 4 Stroke Engine (4 min 40 sec)
(4 min 40 sec)
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Old 02-23-2015, 09:01 PM
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So, if you have blow-by due to the rings not being seated, does it affect the mixture? I'm not saying that you don't have to tweak the needles as the engine breaks in but why?
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Old 02-23-2015, 09:40 PM
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once the rings get seated, there is less blow by. I am guessing here, so now the motor will have more fuel/oil mixture, and at some point, this will have a deleterious effect on the ability to combust the volume of gasoline. For gas engines, we want them to function at peak performance. too much gas/oil can result in excess carbon build up. this can also be bad.
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Old 02-23-2015, 10:02 PM
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Ortho, regarding your mixture question, consider the cooling affect the richer mixture offers a new engine. As it breaks in, that additional fuel and oil that used to be critical to the engine's cooling, are now not so necessary (to a varying degree, as the engine continues it's break in), and can be cut back. This allows the engine to pick up rpm, maybe become a little less picky on it's settings, and just become more friendly to handle. That's my take on it anyway... -Al
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Old 02-23-2015, 10:10 PM
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Two stoke blow-by is essentially recirculated. This blow-by is a mixture of gas, oil and air or spent combustion gasses, depends on what part of the cycle the blow by occurs. Does this actually change the gas, oil and air mixture?
Agreed that once the rings seat, things are more efficient.

BTW, I had to look up 'deleterious'.
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Old 02-23-2015, 10:19 PM
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I hammer at 1500 feet
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that is the medical in me!! sorry.
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Old 02-23-2015, 10:22 PM
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To answer Ortho...usually you "can" lean the engine as it "breaks in"...loosens up...

As for as "Blow-by" goes...some two strokes are designed for EGR bypass..not that we want that in our model engine...Yuk EPA!!! but it goes to show a little blow by is not a great big issue most times.
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Old 05-17-2015, 08:45 PM
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When setting up my transmitter, do I need to have throttle cut and ignition on separate switches? I initially set it up on the same switch, so when in POS 0, throttle was -130% (no stick movement will move throttle) and ignition is off. POS 1 has normal throttle movement and ignition on. But not sure that's the correct way? Does throttle need to move with ignition off for choking?
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Old 05-17-2015, 10:32 PM
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Quote:
Originally Posted by HornetNZ View Post
When setting up my transmitter, do I need to have throttle cut and ignition on separate switches? I initially set it up on the same switch, so when in POS 0, throttle was -130% (no stick movement will move throttle) and ignition is off. POS 1 has normal throttle movement and ignition on. But not sure that's the correct way? Does throttle need to move with ignition off for choking?

What i do: I use an IBEC (Ignition Battery Elimination Circuit). This is a unit that plugs into a channel in the receiver, I have it set up for a two position switch on my Tx that I can reach to with my right hand, that way, when I am taxxing, I can use my left hand for rudder and throttle. This switch is usually "Gear", but it can be whatever you program it to be, I do not know what Tx you are using.

With an IBEC or any other type of optical ignition kill switch., once you flip the switch, it cuts off the power going to the ignition CDI (Capacity Discharge Ignition) unit.

IT is quite reliable, I have used two, the 1st was the PowerBox SparkSwitch, always worked, but required a separate ignition battery (total of 3 for my airplanes).

Then, i have switched to an IBEC from Tech Aero.


to answer your question, all you need is a kill switch. You must have a kill switch, were you can disable the CDI from your remote, for all kinds of reasons, biggest one being safety.

I do not believe you need to set up a throttle cut, as we used to with Nitro, years ago for me.

Ok, on the flip side, you can consider using a high idle/low idle switch. This is so that right before you take off, you flip the high idea switch on, that way, you do not have to worry about engine cutting off if you do a hammer-head or something were you bring power down all the way for a brief period of time, if under load, can cause dead stick. I usually will flip to low idle when i make my approach to land.



Hope I answered your question.
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Old 05-18-2015, 07:22 AM
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I agree with Ortho, the throttle cut isn't really necessary. That being the case, doesn't mean that what you are talking about doing won't work. Might be considered overkill by some, but it should work!
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