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Idle speed issues

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Old 11-04-2019, 07:36 PM
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Default Idle speed issues

I have a slayer pro, its 1 tank into break in. When its running, it has a tendency to move unless brakes are fully applied and when brakes are off it will accelerate to a decent speed. I tried adjusting idle speed but since its in break in i don't wanna, mess with carb settings much. Any ideas? Its been a long time since i was in the hobby. Thank you
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Old 11-05-2019, 12:16 AM
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You are sure the trimm is correctly adjusted to close the carburator at idle?
Maybe an extra return spring is needed?
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Old 11-05-2019, 03:03 AM
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Like already mentioned above, make sure throttle trim is at neutral position.

If this is not the problem, check your idle gap, make sure it is not set too wide. Re-adjust to 1.0-1.2 mm (good for first start up).
Now richen (CCW) the low speed needle (LSN) a few hours at the time, until the idle speed drops to a point that is stable enough,
but the clutch does not engage (truck does not move forward).

Enjoy breaking in your engine
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Old 11-05-2019, 04:33 AM
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I plan on double checking the throttle is neutral when sitting later today. As far as the idle speed screw goes it didnt seem to make a difference in idle speed it would stay at the same rpm then either stall from being too lean or rich. I put it back to about where it was i will adjust it to the spec you mentioned later.
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Old 11-06-2019, 03:00 PM
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Originally Posted by dld View Post
Like already mentioned above, make sure throttle trim is at neutral position.

If this is not the problem, check your idle gap, make sure it is not set too wide. Re-adjust to 1.0-1.2 mm (good for first start up).
Now richen (CCW) the low speed needle (LSN) a few hours at the time, until the idle speed drops to a point that is stable enough,
but the clutch does not engage (truck does not move forward).

Enjoy breaking in your engine
i adjusted the idle speed to the spec given, adjusted the throttle trim and it still takes off at idle. Anyway it could be slipper/bell clutch?
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Old 11-06-2019, 04:49 PM
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Originally Posted by Roelof View Post
You are sure the trimm is correctly adjusted to close the carburator at idle?
Maybe an extra return spring is needed?
i adjusted the idle and trim nothing helped. What else could it be?
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Old 11-07-2019, 12:22 AM
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Did you take a close look? Take off the ait filter and put the radio on.
When slowly giving throttle there need to be a small movement of the servo before the carburator will be opened. If that is not happening then there is something wrong with the trim or total adjustment of the throttle link. Also be sure when letting the throttle go the carburator must close, check it by pushing on the throttle link at neutral position to see if the carburator does not move.

If that is happening then there must be something wrong with the idle screw or maybe the LSN screw.

The only thing I miss in your post is when you put the car on the brake, is the engine going down on rpm or does it stay on the same level.
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Old 11-07-2019, 07:46 PM
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Originally Posted by Roelof View Post
Did you take a close look? Take off the ait filter and put the radio on.
When slowly giving throttle there need to be a small movement of the servo before the carburator will be opened. If that is not happening then there is something wrong with the trim or total adjustment of the throttle link. Also be sure when letting the throttle go the carburator must close, check it by pushing on the throttle link at neutral position to see if the carburator does not move.

If that is happening then there must be something wrong with the idle screw or maybe the LSN screw.

The only thing I miss in your post is when you put the car on the brake, is the engine going down on rpm or does it stay on the same level.
ill check to see the carb movement tomorrow, i have the trim set so the linkage moves before the carb and when its stopped via the brake it will remain near where i think it should idle but once brake is released it seems to want to pick up speed to a given point, running lean i assume since the pitch is completely different and no smoke is being given off. Also when its cold the car drives like it should, its normally only when warmed up i have this issue
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Old 11-08-2019, 12:08 AM
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Then the engine is set too lean. Richen up booth needles or try to go back to factory settings (if listed in the manual)
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Old 11-10-2019, 07:18 PM
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Here are a couple of things to check. First make sure your throttle linkage is not binding and the carb is closing all the way. Also put a throttle return spring or band on it to ensure it also closes in the event of servo failure. Second item, Check the clutch and make sure it is built correctly. Ensure the bearings are good, the clutch bell should have about a 1mm of play back and forth and should spin freely when you spin it by hand if the engine is removed from the car. If it does not, it is not shimmed correctly or you have the shoes assembled with a problem. If the shoes are engaging the same thing will happen that you are referencing.
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Old Today, 12:17 PM
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Exclamation Idle fix for nitro trucks and cars.

Its probably already been said, but reducing the idle speed screw during break in is normal as to that your location and climate may be different then what it was set for from the factory. I would recommend backing it out 1/8 turns at a time until you get a smooth and steady idle. Reducing the idle is not going to damage the engine in any way. Also only make screw adjustments after the engine is warm and you have made some high speed passes to clear the engine of excess fuel.
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