The good news: The pictures sure help. Please do more of that in future posts.

Is the motor stick already glued in? There is a decent amount glued in too, right? If so, AND the cowl is touching the spur gear (the black gear in the front), then, if there is room for the motor to move back, you are going to have to cut a BIT off the motor mount stick off.

A BIT! Make the cut square and slide the motor all the way back on the stick (no need to screw it in) and try the cowl again. Keep doing this until the cowl fits.

Take it slow. If too much comes off, then you'll have an even bigger problem.

Again, before cutting the mount, ensure the motor has room to move back. When you get really close to where everything will fit, you can sand away the wood. Again, go easy with this, If you take 80 grit and go hard at it, the wood will split and you may have a problem. If I'm sanding like this, I'd draw straight lines around the mount of what I want removed using a small square. I'd then sand a bevel all the way around down to the line. Then, I'd sand the 'hump' in the middle.

Take your time and try to enjoy the build. What happened to the front of the cowl shows that you're trying to get it done too quickly. Some mistakes don't matter, some mistakes are easy to fix. Some mistakes means making or buying new parts or worse, making a plane that doesn't fly well because things aren't aligned correctly. I learned this lesson on my first 'performance plane'. I thought the elevator was 'close enough' to parallel with the wing when I put it in. What this lead to was a nasty tendancy for the plane to fall to one side when applying lots of elevator. It caused me to crash the plane on my second time out. The next one I made, I ensured it was parallel.

Many times I and others read threads here about 'My plane only turns to the left' or "This plane is a lousy plane--it doesn't even fly'. We know that the user didn't check the CG, didn't build it properly, didn't set it up right, etc, because we own the planes and they fly, often well.

A habit of good builders is to read the entire manual before the build so you know what's coming and get 'the big picture.'

I take notes as I go along and tuck them into the manual when I'm done. That way, next time I build, I've got a list of what I should have done and things I would like to do for the next build.