Runs. Then doesn't.

It can also be the result of a cracked tube. They sometimes develop hairline cracks near where they meet the bowl. You may need a small magnifier too see them as you look down into the bowl.

Also check the drain tube itself on the inside of the bowl to see if there are any cracks.

hardrockminer wrote:

Also check the drain tube itself on the inside of the bowl to see if there are any cracks.

That is what I was trying to say 

Based on the leak out of the number two carb overflow and the advice given above, I purchased an accelerator rebuild kit from Z1 Enterprises.  This is the recommended kit for a 1979 KZ650.  My question is:  where do the circled parts go?  When I disassembled the pump, I didn't see any of these three parts. Also, I don't see anything about these parts when searching the site.  Thanks again for your help. 
 

In the float bowl.

TexasKZ wrote:

hardrockminer wrote:

Also check the drain tube itself on the inside of the bowl to see if there are any cracks.

That is what I was trying to say 

Don't you just hate it when someone gives the same advice you just wrote yourself?  Funny thing....At the time I wrote it I had just inspected two leaky carbs on my 650 rebuild.  On one the tube was cracked longitudinally almost from top to where it entered the bottom of the bowl.  The other had a much smaller crack.  Apologies for overposting!

Thanks for the additional comments.  I have the float bowl off.   Unfortunately, the two old metal parts dropped out when I removed the bowl.
So, now I don't know where to put the new parts, including the O ring.  Diagram or picture?   First time working on these carbs, obviously.  

Addendum:  I finally found a carb rebuild video which shows the placement of two metal pieces.  No idea what purpose they serve.  I'm assuming
that the O ring is for the drain screw.  Correct?  

The ball is a back flow check. It keeps fuel from going back into the small tubes connecting the bowls. The cylinder is the weight that sits over the ball check. The oring goes around the spray nozzle in the carb body. It seal fuel from leaking out of the bowl. On the bowl there is a bore drilled at the front of the bowl. Inside in this order, from top small fine retaining spring clip, cylinder, then ball check, at bottom. There is that same clip, weight, and check in all four bowls, the reason you only get one setup in the kit is the #2 bowl only gets removed to replace the diaphragms. Grease the diaphragm to keep them from tearing when tightening the screws. Mind how tight you torque them as you can “squish” out the diaphragm and ruin it. 

There is a small spring clip that keeps the ball and weight piece, properly secured inside the passage in the float bowl.  

Green circle shows bore in bowl that houses the spring clip, weight and check. Red arrow is the spray nozzle and that’s where the oring goes