Almost ALL ABC engines are very hard to start by hand AT FIRST.

This is because the engine is not worn in yet and the sleeve and cylinder have an extremely tight fit out of the box.

So tight that you may believe you will break something...

The key is this...

DO NOT cowl or cover the engine until you've run a few tanks through.

On your very first start up attempt, use a heat gun or hair dryer to heat up the cylinder head.

Get it to the point that it is almost HOT but be careful with your plane's covering if you have the engine mounted.

Then immediately prime and start the engine before the cylinder head cools off.

Once you do have it running, run it a BIT rich, not slobberingly rich, for a full tank, taking the engine up and down from about 70% open throttle down to idle and back many times.

After this follow normal break-in proceedures with additional tanks of fuel.

After you've run about a gallon or a gallon and a half through it, you'll find that it will settle in.

Until then run the high end a bit rich and leave the idle a bit high... also if possible use a heavier prop, like an APC.

The slight extra mass helps keep the engine going, especially at first... a flywheel or spinner weight will also do the same thing.

Afterwards you'll find it EASY to hand start, once it has been broken in... usually requiring only a flip or two after priming.