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NGH 25 - Walbro carb

Old 03-16-2024, 05:50 AM
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Default NGH 25 - Walbro carb

This is my first try of a gas engine. I have found the carb has a spring which holds the throttle closed. I don't understand why this is needed if the servo controls throttle. The spring keeps a load on the servo except at closed position. Can someone explain this? Can the spring be disconnected or removed?

Old 03-16-2024, 07:42 AM
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Walbro doesn't make R/C carbs. The make carbs for small industrial engines. It is just that they work really well for our purposes. As such those carbs are delivered to the model engine company just as they would be for a weedwhacker or chainsaw manufacturer. Those applications need a return spring. As for disconnecting it, it is pretty much your preference. The spring may act as a spacer on the throttle shaft so I would check that before totally removing it. Usually the spring just hooks over the throttle arm and you can just unhook it and go on. A far as it goes, the spring usually isn't all that powerful. It shouldn't put that much load on a standard servo.
Old 03-16-2024, 09:27 AM
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+1 to mgnostic
Also before opto-kill switches and IBEC's came along, many used the throttle closing as the main way to kill the motor. In this case if a loss of servo or linkage the spring (if left on) would stop the motor.
Old 03-16-2024, 11:02 AM
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OK thanks for the comments
Old 03-16-2024, 07:35 PM
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Yup, no good reason to remove the spring. Leave it in place but do remove the idle stop

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