Hey Ben, it must be an old FG15-10 or FG15-11 according to the motor that's been installed. If you follow the mechanical rods of the left pedal it will guide you to the transmission valve. it's normal that when you rev the motor up it will move. You can send the pictures to my email (it's in my profile) so I can take a look at it. I see what I can find of this machine.
Regards
Marcb
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