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Old 06-04-2015, 11:54 AM
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On my radio (JR X9303) there is a servo speed function where you can slow down the servo travel speed.

I do have a little lag as I snap it to WOT from idle. Can't tune it out. If I advance it a little slower it is just fine. It is an almost-new engine.
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Old 06-05-2015, 09:13 AM
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The Xipp engine tuning method is described at the beginning of this thread.
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Old 06-05-2015, 04:06 PM
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Quote:
Originally Posted by Vinnie6 View Post
On my radio (JR X9303) there is a servo speed function where you can slow down the servo travel speed.

I do have a little lag as I snap it to WOT from idle. Can't tune it out. If I advance it a little slower it is just fine. It is an almost-new engine.
A gasser will never accelerate like a brushless outrunner. Once its broken in, it might do a little better though. Four cylinder gassers accelerate better, because they get double the number of power pulses/revolution of the crank shaft.
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Old 06-08-2015, 01:57 PM
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First off,Great info here. Thanks to the contributors,
Yesterday i finally got to start my engine. I used a starter for the first time just to make it easier. I've got it running ok on the rich side but i goofed with the lo and hi needeles i got hem mixed.
When i get a chance I'm Going to tune as per in this thread.
One thing i noticed is that when my idle is at 1750- 1850 it not reliable when i blip the throttle, it stalls out. Also when i run it at higher rpms it takes abot 8 seconds forr it to come back down to idle. It lingers at 2200 to 2300 rpm.
This is my first gasser and have read all the what should be done for setup. Plug changed to a ngk off the bat and gapped to What others recommended. Fuel tank has no leaks.
My concern is the unreliably low idle and the step down. Engine is new.
Any help or advice is appreciated.
T.I.A.
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Old 06-08-2015, 04:39 PM
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A 2 stroke on idle can be tuned to literally hum like a V-8. When you advance the throttle at this state of tune, it's going to fall flat on it's face every time. It's way too lean. A single cylinder 2 stroke should have a rather unsteady, rambling idle, not hitting on every power stroke. In other words, rich.

If you look closely at the carb, very close to the needles, many are marked with an L over the low speed needle, and an H over the high - as a reminder to help in case you get confused again.

That "lingering" up on high idle is another characteristic of a lean low speed. It should take care of itself when you get the idle set correctly.

Welcome to gas!
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Old 06-08-2015, 07:07 PM
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Thanks Al.
I rotated my carb for easier throttle linkage set up but now its a little harder to get to the needles.
I've come across this method of tuning the motor before from the original author but was not able to find prior to tuning it yesterday,until i looked here. Glad i did.
I then realized i got the needles mixed up. I made minimal adjustements so they are not far off adjustements

Motor is new and not properly tuned and yet feels like a stump puller.
Dle 20ra. =)
I sure miss and loves me the sound of a i.c. engine
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Old 06-14-2015, 04:20 PM
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My VVRC 40cc twin starts easily and pulls my EF Extra 300 well but won't throttle down for landing. Have to use the kill switch and dead stick it in to get it slow enough to land.
If the low end is leaned it will idle slowly but transitions poorly or quits. If the low end is richened it will idle well and transition well while warming up.... but once in the air and fully warmed up or hot it will not idle down. If the trim is used to fully close the throttle buterfly it still runs at high enough RPM to fly! Have to kill it to land.
My Extra has about a dozen flights on it so far and I'm afraid its going to get worn out before this engine is tuned properly.
Thought I might have an air leak through the carb mounting gasket so put a little torque on the carb mounting screws.
Checked the throttle linkage and changed out to a high torque metal gear servo.
Tried with and without the cowl on.
Reset the needles to factory recommendations and tuned from there.
Nothing fixes it.
About to pull the carb......still suspect an air leak or loose butterfly.
Would apreciate any suggestions.
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Old 06-14-2015, 05:58 PM
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Maybe check the reeds while you're in there...
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Old 06-14-2015, 08:44 PM
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It sounds lean. It could be an air leak, but before going through the trouble shooting for that, you might try going even richer on the low speed. It sounds like you might be getting into the infamous 2 stroke high idle hang.

It's caused by an engine with a hot combustion chamber. Normally, when this engine is pulled back to idle, the low speed metering will be able to supply enough fuel to cool that combustion chamber down quickly, or maybe up to a second or so for a delay. If it takes longer for it to come back down where you expect it, there's a good chance it's lean.

It's not just your engine. Any 2 stroke can and will do this if conditions are right. In our hobby, an engine coming in for a landing is coasting, and as such, the prop is pretty much free wheeling. These are the perfect conditions for this type of behavior to occur.

Bottom line, you could go maybe 1/8 turn richer to see if that helps or changes anything. Easy cheap something to try before getting further into it.
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Old 06-14-2015, 11:44 PM
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Tried rich on low needle until midrange was 4 stroking and still high rpm at idle. When coming down to idle from midrange the idle is initiallly slow but then speeds up after a few seconds.
I pulled the carb and found that the carb mounting flange on the crankcase is not flat. It has a mold mark that runs along half of the flange face resulting in a step in the surface that measures .020 inch. In other words half of the carb flange mounting surface is at least .020inch higher than the other half. The gasket is not thick enough to compensate and may be the source of an air leak.
The surface should have been ground flat. I may cut a new gasket from .030 material along with some gasket sealer to fill the gap.
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Old 06-15-2015, 12:05 AM
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Yep, if butterlfy is completely closed and the engine still runs, then likely there is an air leak somewhere.

A sheet of 320 or 400 grit wet-dry sand paper in a flat surface, like a sheet of glass, flat stone, or flat steel plate, should flatten that mounting flange with a little elbow grease.
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Old 06-21-2015, 08:23 AM
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Hey guys, I have a DLE-170 on a Pilot RC Yak that I purchased last summer RTF. There are 4 each 1/4-20 hex head grade 5 bolts holding the motor onto the motor box. I found the bottom 2 bolts literally sheared in half the other day. I want to replace the bolts with grade 8 bolts but was told not to use grade 8 because they are too rigid. Do I use grade 5 or 8 to replace?
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Old 06-21-2015, 08:43 AM
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You will be better off having a bolt shear than having it take a mounting lug off the engine.
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Old 06-21-2015, 09:46 AM
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Quote:
Originally Posted by PropsnWings View Post
You will be better off having a bolt shear than having it take a mounting lug off the engine.
Grade 5 it is, thanks.
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Old 07-12-2015, 12:26 PM
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on DLE engines how to adjust ignition timing. Manual Says anticlockwise to advance . with engine mounted inverted is this anticlockwise viewed from the front or the back ?
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