Folks that find a gasser , usually a plaining boat that will be run as a displacement boat need to make a check.
Depending on the age of the boat the ignition system may need a change.
AS the engine probably was set to run 3000-3500RPM for long periods of time , the spark plug heat range was selected for that service.
HOTTER spark plugs will be required to run basically just above idle , however there is a danger if these plugs are in when charging at 3500 again of the plugs causing pre ignition.
Simple cure is platinum plugs that have a wide heat range..
Or simply HOT up the std ignition to fire the std cool running plugs.
Take a look at a plug after the first 10 hours of displacement cruising to see what is happening.
Another tip is to take a look at how the secondaries on a 4bbl carb open.
The hot rod folks have a variety of systems to change the opening method.
A swop to mechanical is fairly easy and if set right will allow one to run on the smaller primaries longer in the RPM range.
The de-fuling secondaries are still operable , just tales a longer or harder push on the throttle.