In an attempt to clean the Walbro WB27 carb on my ZDZ120, I took out both hi and low needles. One has a pure conical tip, the other a stepped dia to a conical tip. Which one is which?

I don't know if this will help but the PN for the low speed needle is 102-152. <a target="_blank" href="http://www.kart-mall.com/product/product&amp;sort=p.price&amp;order=ASC&amp;page=2& amp;manufacturer_id=36&amp;product_id=2409">Here is a pic of it if you can make it out.
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Roy at cncengines.com came up with this:

Not positive but check them close, I think they used to make 1 larger thread than other, if not 1 is normally longer than the other. If you have a good light and magnifier you could check the bore in the carb to see which seat matched which needle. I don't get much time on these any more but if memory serves me correctly, if you are careful, you can't get them in wrong. If the threads are the same, leave the springs off and gently screw them into the body. If they are both the same length when seated there in correct, if 1 is a lot taller than the other reverse them. They should be equal height when seated if they are in the correct hole.


Anybody else got ideas?

That may be a generic pic because it is a lot longer than that and both look different. A couple more cups of coffee and I will look closer.

If they both have the same thread....just screw them in until they bottom out (gently!)...when they're in the correct spot the tops of the needles will be flush with one another...when you have them in the wrong spot, you'll see a marked diffenrence in height.

I still wonder why they switched to needles with the same thread... Probably cheaper because of tooling....