Guys

We have a little taotao 110 that we can't get started.

We replaced the carb on it just a few weeks ago. The day we put the new carb on it started and ran like a champ. My kids ran the wheels off of it for a day. They then put it up and tried to start it the next day and it will not even begin to start. Just crank and cranks.

So we have done the following:
1. Took the carb off and clean it out.
2. Took fuel tank off and cleaned it out
3. Replace fuel filter
4. Checked spark at plug. My 14 year old son said he saw spark in the plug gap.
5. Removed CDI box and then put it back on. Didn't really know what is was.
6. Took apart the handle bar kills switch and put it back. All looked clean.
7. Sprayed a small amount of starter fluid into the carb and tried. No effect.

I will pick up a compression tool tonight and check cylinder compression.

When you don't pull the brake it does nothing so we. *think* the brake kill switch is intact.

One odd thing is that when you don't hold the throttle you can here it "puff" on every stroke. It's not starting but you can hear the exhaust puff. However, when you hold the throttle the puff entirely goes away and it just spins.

It doesn't look like it's pulling fuel into the fuel filter. The filter looks almost entirely empty (no fuel sitting in it) so not sure if that means it just doesn't have the suction to pull fuel into it.

Also my son says that when he was working on it before he got it "popping". He said it sounded like it was trying to start. Just popping (not clicking like bad battery or stator). During this testing we had it jumped off my truck so plenty of battery power.

We're at our wits end here. Any idea appreciated!