TOM, I don't have the Carosel but I have most of the other ARC planes and they all mount about the same.

There should be a ring that goes behind the firewall and in that ring you should have to insert 4 nuts in holes. Then you put the bolts through the motor mount and firewall into the nuts in the ring. That will tie it all togeather. Now a note, your fuel tank will have a soft rubber ( ? ) ring that goes over the neck of the tank and slides into the hole in the ring to assist in holding the tank.

AND yes you do have to drill holes to mount the engine to the engine mount. If I remember right it uses a sort of metal screw and you drill a smaller hole then screw the screw in. By the way that plane was designed to have the engine mounted INVERTED, that's why I don't have one. Hope this is of some help. ENJOY !!! RED