email@example.com wrote: 1960 40hp big twin, can I bypass the safety cut out switch? On the side of engine.
Not unless you want to blow up the powerhead! Seriously, that vacuum cutoff switch is there to protect the engine if the throttle is slammed shut at high rpm with no load. In that situation, due to high vacuum in the crankcase, it'll keep pulling fuel from the carb enough to rev dangerously. The switch closes under hi vacuum to short out the points, killing ign & stopping the overrev.
They most definitely can grenade under those conditions. I disconnected the switch once to see what would happen. It started going "ring ding" then "RING DING DING DING DING........" faster & faster. I shut it down with a rag over the carb, starving it of all air.
Anyhow, that's that. Make sure yours remains connected & working. Failing that switch, the only ways to stop an overrev are to block the carb or pull the plug wires. Or install an add-on kill switch. IIRC the manual-start-only models did have a kill switch.
If I do bypass it , I do plan to have a kill switch at engine and up on the remote controls , I was just curious if it can be done . I am starting from scratch, I have no wiring . I traded some work for this project boat . Retired hobbyist here , gives me something to do and enjoyment.