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-   -   Nervous about break in settings. (https://www.rcuniverse.com/forum/rc-car-engines-272/11663452-nervous-about-break-settings.html)

Limsleia 04-14-2019 03:21 PM

Nervous about break in settings.
 
Hi guys. Ive been out of the rc world since the early 2000s. I recently picked up a traxxas jato and ive been trying to get it broken in. I keep getting rained on so thats been stopping me but what im nervous about is that it seems like the idle is pretty high. The car wants to move under its own power just idling. Is that normal? Holding the brakes down it still wants to move. The temperature has been in the 60s. There is blue smoke and spatters of oil coming out. It wont stay running without an igniter plugged in. Any advice or tips? I preheat it to 160f with a heat gun. I havent gotten a tank through it yet even but after each time ive tried to run it ive given it after run oil and made sure the piston is left at bottom dead center before letting it cool. It was my understanding that traxxas engines are set for break in from the factory. I had a nitro sport that didnt seem to have these issues at all but that was a long time ago.

1QwkSport2.5r 04-14-2019 04:20 PM

The initial settings are too rich for most people. Leaning the bottom so it will idle on its own but load up if left to idle for 15-20 seconds is fine. Preheat to 200F, prime and start the engine and drive it. After a half twnknor so, the mixture should be close to stabilizing. If idle is high and won’t drop down, reduce idle gap a little bit at a time. Each change narrowed to the idle gap leans the low speed a tiny bit. Repeat as necessary.

Limsleia 04-14-2019 04:37 PM


Originally Posted by 1QwkSport2.5r (Post 12518227)
The initial settings are too rich for most people. Leaning the bottom so it will idle on its own but load up if left to idle for 15-20 seconds is fine. Preheat to 200F, prime and start the engine and drive it. After a half twnknor so, the mixture should be close to stabilizing. If idle is high and won’t drop down, reduce idle gap a little bit at a time. Each change narrowed to the idle gap leans the low speed a tiny bit. Repeat as necessary.

Thanks for the fast response. Leaning the bottom end. You mean to lean out with the low speed needle? This would allow it to idle without trying to drive off? The extra heat is to try and keep it running under its own power without shutting off?

1QwkSport2.5r 04-15-2019 11:29 AM

Make sure the carburetor is closed against the idle stop when the trigger is at the neutral position (finger off trigger) and the servo trim is centered at zero. If this is how your linkage is setup, then the idle gap is too wide and that needs to be adjusted.

Many mixture changes requiring going richer or leaner is done with the mixture needles. Idle gap is adjusted by the screw on the back of the carb that goes in at an angle. The high speed mixture is on the fuel inlet stem and the idle mixture needle is in the end of the throttle valve (carb slide).


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