The engine height can be checked by looking along the cavitation plate, sighting it with the keel. This engine is slightly below the keel.

Lightly clamping a straight piece of wood to the cavitation plate can also assist to determine engine heights. This engine is below the keel and could be raised.

Most aluminium boats have an extended keel welded to the bottom of the hull. Engine placement is normally in align with the bottom of this keel. Not the bottom of the boat..

This motor is at the correct height.

It is common for the motor to be raised above the transom.

The engine manufacturer provides provision for adjusting the heights.