On my 1984 Commander 410, when I turn on blower, how long should I leave on?Just when I start up the engines?orLeave on as long as engines are on?
Most blowers are only designed to be used part time.
Typically they get run at least 5 minutes before startup.
Like Tim mentioned, it's wise to run them below a fast idle when your deec scoops aren't able to bring in adequate fresh air.
That said , I'm a big fan of upgrading to continuous duty blowers.
I prefer to leave mine on always whenever running my boat.
Running blowers that are not rated for continuous operation can lead to overheating the blower and or circuit.