If you just pulled the top off of the head and did not remove the sleeve it is fine, just re tighten in a X pattern. The reason you feel so much pressure at TDC is the pinch these ABC engines have.

It will take a lot of running before this eases up. It should always have some pinch. If it is real tight it will move the sleeve without the head capped.

The factory setting for the LSN is 2 turns out. It is likely close and should be moved tiny amounts at a time. It is inside the carb barrel in the center of the control arm on the carb. Opposite of the HSN.

The reason you may need to replace a glow plug is new engines can wear a ton and get trash on the coil. Its worth a shot. First do what everyone else suggested and clear the excess fuel out of the engine. Then give it a spin. If it still won't fire try a new glow plug.

If you get it running again it really needs to go through a break in.

Here are some break in instructions from another brand that are as good as any. I hope this is not overkill but I figured it can't hurt. These engines are extremely tight and really do need long run in time.

Clear the engine of fuel as
described above. Do not continue to try and start a flooded engine. The
connecting rod in the engine could be damaged. Never run the electric
starter on the engine for longer than 8-10 seconds. If the engine will not
start in 8-10 seconds something is wrong.
6. The engine should start and keep running, although it may be running
slightly rough at this time. This is normal. Allow the engine to warm up
for 15 to 20 seconds before removing the glow plug clip. Let the engine
run at this throttle setting for 30 seconds and then open the throttle to full.
21The engine should be running at full throttle, but running somewhat
rough, with a lot of fuel/oil being discharged from the muffler. This is
because the engine is running in a very rich condition–that is, more than
enough fuel is running through the engine than is needed. Run the
engine at this setting for at least five minutes.
7. After five minutes, you can start leaning the engine by turning the
high-speed needle clockwise. Never turn the needle more than 1/8 of a
turn at this point. To determine if the engine will accept having the
needle leaned, give the fuel line a quick pinch and release...just pinch
the fuel line and let go. You should hear the engine increase a bit in
RPM, with the sound going up in pitch. If the engine increases in RPM,
you can lean 1/8 of a turn. Allow the engine to run for one minute at this
setting. Now give the fuel line a quick pinch and release. Wait thirty
seconds and do it again. Do this five times. If the RPM increases all five
times, lean the high-speed needle another 1/8 of a turn. Wait one minute,
and then start the pinch and release series again. If the engine doesn’t
increase in RPM when you pinch and release, wait one minute before you
try the pinch and release series again. Don’t lean the high-speed needle
until you get an increase in RPM every time you pinch and release the
fuel line.
8. Keep repeating the “pinch and release” method until the RPM does not
change when you pinch the fuel line. You’ve leaned the engine as far as
possible. Do not ever lean the engine to the point that the RPM decreases
when you pinch the line or severe damage will result. For flying, you want
to set the high speed needle so that you get an increase in RPM when you
pinch the fuel line or when you pick up the airplane and point the nose of
your model straight up. If you hear the engine’s RPM decrease when you
22pinch and release, you must immediately turn the high-speed needle
counter-clockwise at least 1/4 turn. The decrease in RPM tells you that the
engine is too lean, and needs to be run at a richer setting for at least a few
more minutes.
The entire process detailed above can be done by the end of the second
tank of fuel, or part way into the third tank. It should take a little over 1/2
hour to get your engine ready to fly. At this point, you can adjust the idle
mixture setting.
Note: It is always safer to have the engine run a little rich. This will
increase the longevity of the engine and make throttle response more
reliable.