I just finished mine. I used some thin clear plastic (like on the cover of a spiral bound report) with some blue painters tape. Tape it to the fuse and overlay it on the engine and mark the engine cutout with a Sharpie. Cut the clear plastic to the Sharpie line. Then take the engine off and mount the cowl and overlay it on the cowl and trace the cutout onto the cowl and cut it out with a Dremel disc and finish with a sanding drum. Repeat the procedure for the muffler.

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