Trailmaster Mid XRX Carb Calibration

Rocky Rotella

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I have a Trailmaster Mid XRX with an unmodified 168F engine. I regularly use non-ethanol-blended fuel.

Ever since new, when restarting a hot engine I have to crack the choke knob to get it to start. Once started, I can then push the choke knob back in and it idles suitably with an occasional lean pop. I assumed that the idle circuit was lean, so I removed the pilot jet and increased its diameter from .016-inch to .020-inch. Now I have to pull the choke knob nearly all the way out to restart when hot.

1) Short of buying a new carburetor (which I'm not opposed to), where can I source new pilot jets? I'd like to try various sizes, which I can drill myself.

2) With a stock engine, what is the recommended pilot jet size?
 

BrownStainRacing

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I have a Trailmaster Mid XRX with an unmodified 168F engine. I regularly use non-ethanol-blended fuel.

Ever since new, when restarting a hot engine I have to crack the choke knob to get it to start. Once started, I can then push the choke knob back in and it idles suitably with an occasional lean pop. I assumed that the idle circuit was lean, so I removed the pilot jet and increased its diameter from .016-inch to .020-inch. Now I have to pull the choke knob nearly all the way out to restart when hot.

1) Short of buying a new carburetor (which I'm not opposed to), where can I source new pilot jets? I'd like to try various sizes, which I can drill myself.

2) With a stock engine, what is the recommended pilot jet size?
With these clone style engines, they are 2 different carbs that will bolt on and go.

There's China made.
And there's Japan made.
The Japan made carbs are much better calibrated, the circuits are more consistent then China brand carb.

They have different low speed jets and DO NOT interchange with each other.

I would order the BLUEPRUNTED stock air box dyno ducar red 212cc carb from Dover Power.
It's a Ruixing carb, made in Japan, and the best stock size carb available for these clone style engines, imho.

I wouldnt waste money on an over priced carb kit.

Give Jerry a call, I know he can hook you up with the carb you need.

 
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