Mechanical Set-up of throttle linkage
- With transmitter on and trim button set in the middle adjust throttle push rod until 1/2 air bleed hole is covered
- Adjust barrel stop screw to allow full closure of barrel with trim all the way down
- Center throttle trim button
- Turn on plane and transmitter and adjust servo linkage/travel to insure no over run of push rod on
full closure with throttle trim in full close position
- Check servo arm travel to insure 100% opening at full throttle with trim in full open position with
no over run.
Things to understand when adjusting air-bleed carburetors
 | The high speed needle effects the top 3/4 to full throttle |
| The low speed needle controls everything from idle up to 3/4 throttle. |
| Fuel mixture will change in flight when you point the nose up |
| Fuel mixture will change the fuel level in the tank changes. |
| In both cases, a leaner mixture results |
| The mixture at full throttle needs to be a little on the rich side to account for this. |
Method of adjusting needle valves
| Richen the mixture by turning the needle out or counter-clockwise. |
| Lean the mixture out (by turning the needle valve in, or clockwise). |
Adjusting the Carburetor mixtures
Start the engine
- Allow engine to run at moderate speed for a couple of minutes
for full warm up.
- Give it full throttle,
- Lean it to it's highest rpm
- richen it 1/4 quarter turn.
- With the glow plug igniter still attached slowly close the throttle to the
lowest rpm that the engine will still reliably run.
- Remove the glow igniter.
If the engine dies immediately it's too rich
| Lean out the LOW SPEED NEEDLE (clockwise) 1/8th of a turn
(don't touch the high speed needle) |
Start the engine again
- Give it full throttle up to clear out excess fuel
- Slowly close the throttle again.
- Remove the glow igniter
If it dies
- Lean the low speed another 1/8th turn.
- Repeat the above procedure until you can fire it up and remove the glow igniter with out
the rpm changing "AT ALL"
Test Low Speed adjustment
- Open the throttle quickly and listen to the engine.
- If the engine blubbers and then dies the low speed needle is to rich.
- If the engine hesitates it is to lean.
Re-adjust the High Speed needle
- Lean the high speed needle to it's highest rpm and then richen it 1/8th of a turn to give
it a slightly rich mixture.
- CAREFULLY pick the model up and raise the nose to at least a 45 degree angle while listening
to the engine.
If the engine sags
| Richen up the high speed needle 1/16th turn. |
Try it again
| Repeat the above procedure until the engine doesn't sag or shows a slight GAIN in rpm. |
Proper adjustment of both needles should allow the engine to idle
for prolonged periods of time and still respond instantly to the throttle.
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