Tillotson PK 1B carb questions

Installed Tillotson PK 1B carb on my 212 preditor engine. It is running way rich at idle. some black smoke, plug is soot covered. Every article ive read shows this carb with 2 mixture screws, high and low. My carb has only 1 mixture screw. According to the sellers info, it has an .039 main jet and a .028 idle jet. I tried to measure idle jet with some tiny drill bits and a digital caliper. From what i see it has an .020 idle jet (black plastic). Cant find any different sizes of the idle jet. The only one i found is an .020....Is this carb supposed to idle rough and rich? I have the fuel mixture screw turned out only 1/2 turn. am i missing something here?? Kart is not ready to run, so ive only had engine idling with short bursts of throttle...seems to run good at high speed. should i be looking for a smaller idle jet? should i not worry what it does at idle? Is there something else i should be looking for? For info purposes, it has a CL2 cam and 8 degrees advanced igition timing. Please help me.....
 

flattop1

Dawg 89
You may want to open that idle air screw up some .
2 turns .
Its not a tilly racing carb so no idle and high speed needles.
At this point i would not be concerned .
 
You may want to open that idle air screw up some .
2 turns .
Its not a tilly racing carb so no idle and high speed needles.
At this point i would not be concerned .
Thanks for the response Flattop...I was under the impression that was an idle fuel screw, that's why i turned it in so far. But if its an air screw, that may fix me up. Thank you
 

1fasttiller

Member
These carbs are purposely jetted very rich on the low end to assist with throttle response and take off. You don't race at idle... Dover's holy moses carbs will foul a plug in 3 minutes at idle.
 
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