Found problem with forklift. Problem was in carburetor. Rebuilt carb and gave tuneup. Started on first try and runs like new. Still can't figure out why it would not start with starting fluid. Had spark.

You feel good suction at the mouth of the carb? Did you check compression with a gauge? If so, I would guess it is a spark problem. It should have at least made an attempt tp start with the start fluid or gas.

We pulled up compression stroke on number one cylinder and checked rotor to see if it jumped tine. Checked vaporizer and regulator. We even pored gas strait in and tried starting. Pulled plugs and were not even wet or smell of gas. Compression and suction at carb. feel good. Fuel is not getting into cylinders. Starting fluid , it doesn't even act like it wants to fire. All plugs stay sparking when spinning engine over.

Check diaphragm in mixer, probably blew a hole in it.