Some more carb questions

T

TAM3THEBEAST

New member
one of my carbs that i got back from the engine builder wouldnt run on the track but it ran on the dyno. i took both of my carbs apart and measured the float and everything and on the newer carb that doesnt run and it was within the specs of what it should be, i took apart an older carb that works and measured the float and everything and it was quite far off but it runs better than the one that on paper should run better, the engine builder put it through the ultrasonic twice and dynod it a few times and it ran perfect. any suggestions on whats wrong with the carb?
 
Are you sure you don't have a plugged jet? Can swap from to the other? Otherwise I would say you need to provide more info on what setup you gave in the carb that won't run.
 
Over the years we have had some cards that just don’t work correctly. Those are in a tote and marked lemons. My suspicion always was these carbs had some debre maybe from the machining process that was lodged in the small hole circuitry in the carb main body. Not really sure , but I never had the time to spend hours hunting for the problem, we just replaced it and moved onto the next engine. In the 20 years we have been building the Animal engine I think we have about 20 carbs we deemed lemons. Not too bad considering we’ve built thousands of engines. Honestly we had more problems with the older version walbro manufactured carbs, the newer style Briggs carbs seem better.
For those of you that have on kart A/F ratio data acquisition systems, a lot could be understood with that type of real time track testing related to carburetors. The dynamics of the fuel in the bowl are significantly different in a carb running on the Dyno as compared to race tracks.

Steve
 
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Also....look to see if the brass plug/bowl vent is still in the carb body, as well as the "Ball Plugs" that cover the cross drill passages.

We have seen an abnormal amount of those falling out during the ultrasonic process, or while racing, and going unnoticed.
 
ill take a look at if i have a plugged jett, i know its not a lemon since i used the engine before the carb stopped working, ill also take a look at if i have the bowl vent in there
 
I found black flecks in a new carb that would not run. Near as I could determine it was plastic flashing on the float at the mold lines
 
Michael Curry said:
Also....look to see if the brass plug/bowl vent is still in the carb body, as well as the "Ball Plugs" that cover the cross drill passages.

We have seen an abnormal amount of those falling out during the ultrasonic process, or while racing, and going unnoticed.
Click to expand...
^ This ^ right here.

If it occurs during ultrasonic cleaning, they'll be easy to find and replace.
If they fall out during a race - you will instantly notice the change in performance...and the little brass ball will be found laying in the bottom of the bowl.

Now...IF a brass ball plug fell out during cleaning, there's no way it would have run correctly on the dyno.
Even if the floats are heavy, it wouldn't have run right on the dyno.

OP, are you sure that the float drop measurement is correct and that the drop tab isn't slipping over the end of the cast post that holds the float hinge pin? I've seen that problem many times.



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the builder doesnt know whats wrong with it either, i have it right now as he is busy with nationals so ill make sure to check everything you guys said. thanks a bunch everyone
 
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