Misspoke about about the carb couldn’t be the problem. It still needs to control the air.
The fact that the caps are torn up is an indicator that someone who had no idea what
he was doing has been into this motor. You need to remove the caps and check they
are not cross threaded and they have gaskets, any indication the springs have been
meas with, or any damage to the valves or seats so the cant seal. If the valves don’t
seal it won’t start.
Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.