Kazuma 50cc 4 cycle - ran last week. Pulled it out to let the kids play, and can't get it to start.

Has fresh fuel
Fuel getting to carb and into cylinder
Has spark while grounding to block - even tried a new plug (plug wire sparks to engine even without spark plug in - is this an issue?)
Starter cranks and turns over
I've tested the rear and side safety switches
headlight comes on dim while trying to start
Tried some starting fluid in the carb and in the spark plug and doesn't even try to fire - usually a little eather will make it pop... This is where I'm stuck.

What am I missing?

I tore the carb apart and cleaned it all up so that's good

I'm wondering if a safety switch is still grounding out the plug, but would I get spark out of the cylinder then?

Normal starting sequence - turn key on, crank starter. Brake does not need to be held down on this model. Back safety switch is open until pulled, then ohms out. Side safety switch is closed and opens when pulled off. Handlebar switch is on - when off, it won't crank.

Thoughts?

We'd love to take this with us this weekend, but as it stands now, Dad can't get it to run!!

Thanks!

bz