2001 Mercury 40hp 3 cyl 4 stroke, dead

[Rhwells]

My Merc just quit in the middle of the lake. No sputter no nothing, just dead. After getting it back home, new gas filters, checking fuel pump, new plugs I found no spark. Each cyl has it's own coil so following wires back from the coils, straight to the ECM. I only have DVM for static testing. I've checked the Regulator, the stator coils(pulse, charge, lighting), the crank shaft sensor and oil pressure sensor. All resistance are in spec. I have no info on how to check the ECM.
If the engine won't start can you do dynamic testing on any of these components? Where do I go from here?
Thanks

 

[CharlieB]

Re: 2001 Mercury 40hp 3 cyl 4 stroke, dead

Need serial # to be sure.

Switchbix or CDM coils?

Both systems use a 'Ground-to-kill' wire that is Black with a thin yellow stripe. Disconnect this wire at the motor and retest for spark. If it now sparks there is a short in the ign switch, lanyard, or boat wiring.

If still no spark download the free Ignition Troubleshooting Guide found on the Support pages of CDIElectronics

Their excellent guide details the testing of all outboard ignitions.

 

[Rhwells]

Re: 2001 Mercury 40hp 3 cyl 4 stroke, dead

s/n 0T291160
I have no stop lanyard kill switch but I found what you're talking about in wiring diagram. With no laynard kill switch the leads for the laynard are shorted together which puts the ign switch in line for the blk/yel wire control. The switch box ,you called it, I think is the same thing I call the ECM and I have no way to diagnos this. I've been through all coils staticly.
I'll also check out CDI.
Thanks

 

[Rhwells]

Re: 2001 Mercury 40hp 3 cyl 4 stroke, dead

I spun the engine over and checked the output of the regulator and it said 10v. I unplugged the output of the regulator, spinning the engine over (with no load) it was at 2v. Does this say my regulator is bad?

 

[CharlieB]

Re: 2001 Mercury 40hp 3 cyl 4 stroke, dead

Go here and see if the factory service manual is still available for download. You will need a utility like WinRAR or equiv to unpack the compressed file. Remember the password 'ribforum', it will ask for it to unlock the file.

You may have the CDM ignition coils, each coil has a 4 wire plug connected. Each has the black w/yellow 'kill' wire, a short in the igniton switch, lanyard, or wiring harness will kill all spark.

The yellow wires from the stator are battery charging only, going to the regulator/rectifier. Voltage on the stator side will be low at cranking speeds.Disconnect the yellow stator wires and retest for spark. Do not assume anything is bad until testing proves it bad as there is NO RETURN on electrical parts.

Download the service manual and follow the directions for troubleshooting 'No Spark'

Keep posting your progress.

 

[Rhwells]

Re: 2001 Mercury 40hp 3 cyl 4 stroke, dead

I don't have the CDM ignition coil set up that you talk about. On my engine each ignition coil has a two wire connector, which is fed by the Engine Control Module (ECM). The kill wire, blk/yel, goes to the ECM and checks out also. The pulse coil (grn/wht-wht/grn wires) which is another coil in the stator feeds the ECM. The pulse coil staticly checks out good with 680ohms. So I think i'm down to the regulator dragging down the system causing low volgate to the ECM or the ECM is bad.

Can't seem to get into the CDI support. What user name is it for the "ribforum" password?