Mercury 225 EFI will not start

[RBROWN]

I have a 1999 Mercury 225 EFI that will not start. The only time that you get a spark at any of the plugs is when the key is returning to the off position.<br /><br />Any Suggestions?

 

[ODDD1]

Re: Mercury 225 EFI will not start

Brown if i remember correctly this ignition system has the ignition coils making ground through the computer tomake a spark. a spark at key on/off means you got power at the computer and coils, but the puter is not 'triggering' the spark. first [easy] thing to check is the air gap on the crank position sensor under the flywheel. there is a toothed ring under the ring gear on the flywheelthat with the sensor tells the puter which cylinder to inject/fire. air gap betweena tooth an sensor i think is about 040" other than this, sensor may be bad or the puter might be in the dumper........

 

[MERCMAN]

Re: Mercury 225 EFI will not start

CHECK STOP CIRCUIT BY GOING TO KEY SWITCH DISCONNECTING THE BLACK WITH YELLOW TRACOR SPIN ENGINE OVER AND SEE IF SPARK COMES BACK IF IT DOES IT IS THE MAIN HARNESS OR KEY SWITCH ALSO YOU MIGHT TRY PULLING MAIN HARNESS ON ENGINE APART AND SLIGHTLY SPREADING THE MALE PINS APART AND PLUGGING TOGETHER AND TRY IT THESE ARE BAD ABOUT NOT MAKING GOOD CONTACT ALSO ON THE FLYWHEEL SENSOR UNPLUG AND REPLUG