I have an Evolution 15cc pumped carb gasoline engine. HS set 1.5 turns out and LS set 4.5 turns out as manual says. Everything is connected. Prime it, turn ignition on and nothing happens not even a kick.

Just received this engine as a replacement from Horizon Hobby for one that worked but the throttle barrel was binding. Put the replacement on my airplane that the other engine came off and it will not fire up.

Getting plenty of gas and air. Maybe the spark plug is bad...on a new engine?

Any ideas?

The engines need three things to run, fuel, air and a spark. You can check the sparking by removing the spark plug and connect it to the spark plug cable. Turn the engine over and you should see a small spark occur. It will spark even when you turn the crankshaft backwards too. Just use the spark plug though. Do not try to see how big of a spark you can get as that will damage the coil inside the CDI unit.

It just occurred to me, do check to make sure the timing sensor is plugged in correctly, it is easy to get it plugged in backwards with the connectors crossed.

I suspect the ignition, spark plug or battery too.
You say you received a new engine for one you sent back. The one time I had an engine failure with HH I just sent the engine back and kept the ignition, muffler, and accessories.
Is this what you did ?

Yes, I kept the ignition, muffler etc...

I found my problem, you were both right about air and gas, the engine was getting both. It was not getting spark.

Pulled the engine and saw that the timing sensor wire had the white wire pulled out of the connector.

Corrected the problem, hopefully that will do the trick.

Thanks for the input.

Engine fired immediately after repairing the wire that pulled out of the timing sensor connector.