merc no start, spark on left side cylinders no spark on right side of motor any help?

[bigmrmike757]

Hi Guys,I have a 2000 mercury225 EFI No start, I was checking for spark and
found that the left bank haas spark and the right side don't, what could cause
this problem? Any help would be great. Thank YOU Mike

[CharlieB]

If you model has the two ignition modules each firing one bank of cyl's, there is two test to determine if you have either a bad stator or a bad module (switchbox).

First test, disconnect the Bias wire (white) linking the two boxes together, retest for spark. NOTE: Do NOT attempt to start the motor. If you now have spark on all cyl's (both banks) then the Bias circuit in the box that was always working is bad and blocking the other box from firing. It is recommended to replace switchboxes in pairs unless they are already been replaced witih CDI Electronics boxes in which case it is only necessary to replace the box with the bad Bias circuit. Note; a switchbox with a bad Bias CAN be used on a 3 cyl engine (75 to 90 HP).

If still no spark on one bank then proceed to the second test.

Switch the red and blue stator wires between the boxes, then retest for spark. If spark moves to the other bank of cyl's then the stator is bad.

[Faztbullet]

That engine does not have switchboxes or high/low stator as its a 3.0l. Your engine has a "bobbin" style stator and CDM modules. It sounds like a diode has failed in a CDM/s and shorting out a bank. These CDM's share common connections so if one fails it can effect one or more modules. Go to CDI Electronics website and download the troubleshooting manual for your engine and test the ignition system. You also may have lost a ignition ECU but havent seen many of these fail and most problems where due to bad/loose and corroded connections.

[jeffersondodson561]

What is your serial number? Does this engine have CDM's?

cdm.jpg


If this is the one with CDM's, sounds like one of them is shorted to ground through the Emergency stop circuit.

[jerryjerry05]

Profile and serial# for the motor please.It helps to know what motor your working on.J

[Faztbullet]

Also check the shift interupter switch as it kills one bank on some models, serial # will help narow it down ....