Small Engines (Lawn Mowers, etc.): B&S carb, drill press vise, brass nozzle

Question
B&S Model 170402, Type 0714. 2 piece Flo-Jet carburetor. Before cleaning the carb that is now on my snowblower, I remembered last year someone gave me an assortment of parts, including a couple carburetors. One is identical to the one on my snowblower.

Thinking that one may work I took a closer look. The needle valve screw is missing and the slit in screw out brass nozzle is almost non-existant. Is there a way to get that nozzle out with the screwdriver slot damaged?

I put the carburetor in a drill press vise and put a hollow ground screwdriver bit in the drill press. After getting everything set up, I got the bit tight in what is left of the slot and turned the drill chuck by hand, but there wasn't enough of the slot left for even this to work.

What is the required fuel line size for this engine? The line I removed is marked 5/16", but the 5/16" replacement at the hardware store was larger for some reason that puzzled even the guy working there, so I put on a 1/4" line. Could that cause fuel starvation?

Answer
1/4 inch fuel line.  

Removing the old jet can be challenging.   You can drill it out, but you have to be very, very careful not to drill too deep.

A better method is to use an easy out/screw extractor.  Be careful which easy out you use.  I once tried the fluted spriral style easy out and ended up cracking the carb as the easy out tried to pull itself into the hole I drill in the jet.

I have had success with the tap in style easy outs.  This style has 4 sharp edges that bite into the material as you gently tap on the top of the easy out with a small hammer.  I actually had to cut the easy out off so it would not go in too deep.

I'm sure Snap-On and the other pro tool trucks probably sell something better that would work.  I have left handed drill bits but have never had any success removing tight/seized fastners.  They work great is you just snap the head off a bolt during assembly but that's about all.

If you end up needing to tap the thread after removing the jet you will need special taps, 1/4 inch 32 threads per inch...not something you can be at Sears and I doubt too many of the tool trucks sell them.  They are available from Briggs.

Is the engine running lean which is leading you to believe the engine is fuel starved?  

Eric