The carb settings following are starting points for the High Torque engine:
For the WT668 it is 1-7/8 on the low and 5/8 to 3/4 on the high
For the WT603 it is 1-7/8 on the low and 1 to 1-1/8 on the high
For the WT644 it is 1-3/4 on the low and from 7/8 to 1 on the high
For the WT488 it is 2 on the low and 1/3 to 3/4 turns on the high
For the WYK33 it is 7 turns on the low and 1-3/4 on the high
When setting your carburetor, you must realize that the low speed needle needs to be set so that the engine sounds rich and dirty when it is on the stand. It will even sound this way when it is in the water when you are running at low speeds. If you try to set the low needle so the engine is real crisp and responsive, in other words it sounds really good on the stand, this is too lean of a low setting and it will bog in the water when you try to accelerate. For the most part you can set your low needle to our recommended settings and just leave it there and not adjust it at all.
The High Speed needle is another story. You will need to move the high needle to find your best performance. If you get the high needle too lean, you will have less mid range torque. A slightly rich setting gives your engine more torque. Too lean of a setting on the high speed needle will also make the engine flatten out on the top end.
This is where to look to see what model butterfly carburetor you have. Note the WT is the type of carburetor and the model as shown here is the 644. The carburetor type will be on the top and the model will be directly below the type. The number to the right of the WT is NOT relevant, ignore this number. This is a WT644 carburetor in the photo.
The carb settings following are starting points for the Pioneer shipped after 6/15/11
For the modded WYK33 carbs, the 26cc Pioneer High 2-1/2 turns Low is 2-1/4 turns
the 29cc Pioneer High is 2-1/2 turns Low is 2-1/4 turns,
see below for settings for older carbs
NEWEST MODIFIED WYK33 CARB LOW SPEED NEEDLE INFORMATION: AFTER 6/15/11
The low speed needle of the WYK33 carburetor is in the center of the carburetor barrel. Use a small precision flat blade screwdriver to adjust it. The newest versions of the modified WYK33 carburetor use a longer spring under the low speed needle. No Loctite is needed with this longer spring. With this longer spring the starting setting for the low speed needle is 2 turns out.
+2 mm Stroker Pioneer 30.5 cc Needle settings.
Very important, you will notice that you are going to probably need a lot leaner needle settings with the +2 mm Stroker engine. 2 to 2-1/2 turns out is not unusual at all. As you continue to lean the high needle it will get faster on the top end, if you lean it too much it will start to flatten out and you will need to back up a little. The tricky thing is if it is too rich, it still sounds and runs fine. It just does not make as much power as it could if you set it right. This makes it a little bit hard to nail down because there are no obvious signs that you are too rich. The bottom line is don't worry about what the turns are, just set it so it goes the fastest.