• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

25SS idling adjustment

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
A

AKIRA KOSUGI

RCTalk Member
Messages
25
Reaction score
0
Points
0
RC Driving Style
My engine runs too fast at idling, and it needs to use brake to keep the car stopping. Yes, I have adjust idle screw to minimum position but it's still too high. Does Low-Speed Needle works for this solution? I've never adjusted this needle before.
 
Make sure before you start cranking on the low speed needle there's not another problem. How much "Gap" is there at the end of the carb slide? Factory setting is 2mm or .078". Also, check for air leaks. You might be sucking air in at the base of the carb. Loosen the carb, press down firmly on it and retighten. Check the carbs o-ring while you're at it.
 
-xmas- Thank you for good information. 2mm gap is OK, so I'll check the carb. air sucking.
 
Check your idle trim on your radio too, sometimes that moves. I don't recomend messing w/ the low end needle. you can richin it up on the high end to idle down the motor some. If it doesn't work you've got somethin wrong somewhere.
 
If everything else is OK, you might have your Low Speed Needle LSN too lean. Adjust slowly by turning it counterclock-wise 1/8th of a turn at a time (this will riched it up). After each adjustment, run the truck around a couple of times and check the idle.

The truck should idle for only 20 seconds before the carb loads up and the engine quits. Make sure when you check the 20 seconds that you clean it out first by running it a couple of laps.

Good Luck,
RobH
 
One last step on the LSN adjustment. After you "clean out" the case (wide open throttle for a few seconds), let it idle for a couple of seconds and pinch the intake fuel line. If the engine dies immediately, the LSN is too lean. If it idles for a couple of seconds (2-3) then speeds up and dies, it's just about right. If it runs for longer than 4 seconds then slowly revs up and dies, it's too rich.

After you get it set right using this method, fine tune it by letting it idle for about 5 to 10 seconds and then nail the gas. If it bogs down, the LSN is still too rich. If it takes off without bogging, it's just about right.

As for your high idle problem, if the gap is set right (and a couple of my mills have 1mm gaps) and it still won't idle down, then there is some other problem. As stated before, check the carb seat, intake and pressure lines, tank integrity and if you're running a filter make sure it's sealed and free of air leaks.
 

RC Builds

Back
Top