Blue box on 4d61 engine

[Sprig1]

Hi I'm being lazy here does anyone know what the blue box on the back of the 4d61 does. I think it's for the charging system or maybe the glow plugs. I haven't traced it out. It looks expensive and hard to find. I have a friend trying to convince me to put a single wire alternator on the motor and rip everything else off. It's very tempting to make it simpler. Thanks

[hetek]

It is the glow plug timer circuit box. It activates the glow plugs when you turn the key on and has a 7 second timer to prevent from burning the plugs out. Mine was defective so I replaced it with a heavy duty solenoid and a push button on the dash to activate it.

"One Mississippi... Two Mississippi..." took care of the "7 second timer" function.

[Sprig1]

Thanks Hetek I think I'll just pull the blue box off now and rewire it. Since I'm redoing most of the wiring now. Thanks again Chris

[sail149]

The blue box is linked to the starter wiring t had trouble getting my rebuilt starter working until I hooked up the wiring correctly
Warren

[Sprig1]

I pulled off the blue box today. A friend helped me rewire the motor. I have the glow plugs wired up to a switch on dash. The motor actually turns over when we finished. Now to get it started. Albin had the alternator output wire run up to the dash and back down to the starter. This time just ran it around the back of motor to starter. It wasn't to bad and now everything is easily replaceable with off the shelf parts. I never thought it would take this long to complete the boat. I should of known better. Everyone told me it would.