ya that's the way mine were to, and it probably wasnt ur allen wrenches, i had to grind to head of the screw off that i couldn't get loose, and then i had to buy a new motor mount

for the gear mesh, once you get the motor screws loosened, just slide the motor in until the clutchbell and spur gear touch. they should not be too close that it binds when you spin the wheels or spur gear, and it should not be so loose that there is give between the gears. use the paper test method, which is where you slide a piece of paper between to 2 gears and it should come out crinckled. the width of the paper should be the width of the mesh