Bad ECU on a 94' 175efi mariner

firedude

Cadet
Joined
Jan 21, 2009
Messages
6
Boat would start, would idle for awhile then run itself out of gas, after many months and many parts(shop covered cost of parts). A bad ECU(the brain of the motor) was at fault (expensive item!). Boat now runs like brand new. Was told that these rarely go bad, and that it couldn't be the problem, and this was the first one that this boat shop(reputable shop) ever had to replace. Has any one ever had to deal with Merc/Mariner to get some sort of compensation. Or would I be beating my head against the wall.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,931
Re: Bad ECU on a 94' 175efi mariner

Your problem was the fuel pump driver circuit in Ecu. This is a common problem usually caused by the pump drawing excessive voltage. The driver board varies the voltage to pump and if pump was bad or varnished from long storage these will fail. These also can be sent off and repaired for about 1/2 what a new one costs or like we did when we raced was bypass driver with a relay and switch to pump. Pump ran at full pressure all the time this way and I have replaced quite a few of these on customer boats.
 
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