206 rpm/gearing


Dawg 89
If you suspect the fuel pump and intend to race change it and all the fuel lines .
I liked safety wire double wrapped then twisted to prevent air leaks . Others like zip ties . I found them problematic .
No 2 .5 ft air bubble is not normal .

Will P

This is only our second race and I didn't have the tool to measure slide opening so I really had no way of knowing what it was. That's crazy I know. I had a locking cap but now way to set it. I looked around and found a 3/8" socket measures 9/16" OD, more specifically .563" and when added to a 1/4 drive extension makes a good home made setting tool. I found was I was getting .486" (OD of the ratchet/big end of a 1/4" drive extension) opening because I had bound up the throttle return spring in the slide and it was coming out between the top of the slide and the cap therefore stopping the slide's upward travel with a few coils of spring. I recall a video about that somewhere now. Pulling slack out of the throttle cable and reinstalling the slide with return spring pulled tight against the cap gave me .570 plus so I tightened the cap down to .563" and set it.

I don't know if this helps my other woes but was very excited to have learned this. We'll find out shortly.
^ Also having the wrong throttle cable causes problems -- I've seen guys use the standard ball end cable in these slide carbs and it is troublesome at best. There are appropriate barrel end throttle cables for our engines. If anyone needs them, your local kart shop should have them in stock...if not, give us a call.

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

Will P

Thanks for all the input. We won the first heat and the feature! I recall noticing we have the barrel end. I don’t have a spare cable yet but now I know which one to order. Thanks again.


Based on your description of the problem, I suspect a float issue. There was a batch of briggs carbs that had a variance in the posts where the float is attached. As a result of the variance, the drop tab allowed the needle to "drop" to far often resulting in it getting jammed and allowing too much fuel to enter the bowl. The symptoms would be issues would largely be stumbling in corners....mid to exit. Furthermore, the needle is getting bounced around and will sometimes work fine and others get caught and not shut off fuel.


Dawg 89
Glad to see you back Jimbo .


I am running a #219 chain with a 19/64 and I am barely hitting my rev limiter unless its a LONG straight away. So I'm interested in this topic as I try to find information, as much of it seems to be #52 chain which seem more prevelent in 206. Gearing is something I'm not super knowledgable about.


Dawg 89
Add two teeth in the rear . Check lap times . If its better .
Add 2 more check lap times .
If slower drop one tooth . Check lap times .