Understanding the “Mag Switch” & Cummins Marine Engine Starting Circuit

Why the “Mag Switch”?   OR as it should be called… “Starter Control Relay” Many new starter units are coming supplied with solenoid control relays. These are the small solenoids mounted closely to the starter solenoid. The 39MT series Delco come with … Read More

The Story of Cummins & Mercury SmartCraft “AKA SmartCRAP”

“SmartCraft” is a Mercury thing that started with their electronic outboards and is still the backbone of their gas engines & outboards. There have been so many changes and revisions over the years that even the Mercury “lifers” can’t keep … Read More

Cummins Fuel Shutoff Solenoid Wiring

Black = GROUND White = SUCK IN Red / Purple = HOLD OPEN

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