I use a hoist (I'm old) and I find the motor wants to do a counterclockwise pirouette into the frame from the right side (as your pic). Put the rear in first (perhaps 20* from parallel) and let the back of the motor (dished part) rest against the rear frame backbone above the back mount. Now rotate it in until it clears the bottom center mount. It should then wiggle into place and lower into the back and lower mounts simultaneously. Start with the bottom center mount bolt, then rear, then front, lastly the top. All left loose until all-in. Sometimes the rear mount bolt first, then bottom center.