juanes,

I have a ZDZ50NG that was very hard to start also. Try the following:

1. Throttle-wide open, choke-closed, ignition-off. Flip until fuel is drawn into carburetor. Then:

2. With throttle wide-open and choke closed flip five more times. Ignition is still off. Then:

3. Open choke, throttle wide open, ignition off, flip five more times. Then:

4. Turn on ignition, choke open, throttle set about 30% (or a bit more) open...restrain the plane...be safe... flip until it pops or starts. If it just pops and putts a little repeat the above procedure and try again.

After the engine is run very little it becomes much easier to start. Mine required more throttle to start the first few times. It would not start with the throttle at high-idle. My initial concern was flooding it by using the choke too much. That was not a problem. It required more fuel for the first several starts than I though it would.

Mine has a few hours on it now and will start with less throttle. Flying it seems to be the bes way to break it in.

BE VERY CAREFUL when starting with the throttle at 30%. BE CERTAIN to have the airplane well restrained.

Good luck with your engine. rlmcnii