Plate Jet question

What high and idle jet is recommended for blue plate and what for purple plate? How many turns out on the air bleed? Also I have seen some emulsion tubes with solder on the top sets of holes is this needed?

I seem to have a scavenging issue coming off of wot when stand testing my daughter's engine.

Thank you


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.022" pilot & .052" main should get you close, BUT so much depends on the size of your main nozzle, whether it's .104, .106, .108, or .110" and which needle are you using (BGB or BHA?) Then you've got clip position, etc.
You don't need to plug the top holes. Been there, done that, didn't see the results I was after.
Running an engine with no load will tell you nothing (other than maybe the tensile strength of the rod bolts.) :cautious:
Running on the track, or on the dyno is the best way to tune an engine.

🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN


You can fool some of the people some of the time
It's impossible to answer your question without knowing all the other parameters of the carb. The size of the nozzle determines the size of the main jet. The size of the main jet is influenced by the size of the idle jet. The needle clip position is determined by the idle and the main jet size. the idle mixture screw position affects overall mixture.
I think Steve Baker has a jetting chart in his sticky post at the top of this page.