1993 Mercury 175 EFI XRI Won't Idle When Warm

[m175]

I have a 1993 175 HP Mercury EFI XRI that does not idle when warm. When first started in the morning or after sitting for a few hours it will usually idle well. It runs well on plane through WOT but as soon as you drop back to idle it will die and is very difficult to restart. Problem started after sitting over winter, new plugs and water separating fuel filter have been installed. Have also run nearly 2 tanks of new gas (Approximately 45 gallons total). Temperature gauge is reading normally. Thanks for your help.

 

[CharlieB]

Re: 1993 Mercury 175 EFI XRI Won't Idle When Warm

Check the vacuum line from the intake to the Computer box, droplets oil reversion past the reeds can accumulate, restriction the small oriface in the line and the computer cannot accuratly 'read' engine load/idle once off the coled engine circuit.

You may need to 'read' the computor vacuum sensor value, that sensor could also be 'out of range'