Hi

I am going to go on the assumption that the engine is the Onfa Picco .26 and not the standard Onfa .26 engine.

The carburetor on the Onfa Picco .26 has two known flaws.

1. The o-ring on the high-end needle has a bad habit of getting mangled when it’s installed at the factory. So check the condition of the O-ring on the high-end needle and make sure that the hole the needle goes into is also clean. If the o-ring is mangled you will have to get a new one.

2. The other known problem is with the low-end needle itself, older versions of the engine came with a black Low-end needle that had a squared off needle head (see image below). The newer engines come with a silver low-end needle that comes to a point at the end instead of being squared off. If you have the old style low-end needle you will have to contact Ofna and see if they can send you the new style.

You will also want to apply some high temp RTV sealant in-between the Carb and the block, and in-between the back plate and the back of the engine block to help eliminate air leaks.

The high-end needle on my engine is 5 1/4 turns out, I don’t know how many turns out my low-end needle is but see the picture below for an idea of how far it is out.