97 Johnson 40HP with no spark

willno

Cadet
Joined
Aug 10, 2008
Messages
13
I have a 97 Johnson 40 hp that's been setting up for about two months. The last time I used it it ran great. Today I tried to crank it and it never fired. I checked and it had no sprark on either of the two plugs. I checked the ignition switch to make sure it wasn't grounded and it was OK. I checked the charge coil under the flywheel and it ohmed out as the manual said (800 ohms) and I checked the pick-up coil which also ohmed out as the manual said (28 ohms). I checked the two ignition coils primary windings and the secondary windings. The primary windings were a little higher that the manual called for but both the same and one of the secondary windings was a little higher that the manual called for but nothing was shorted to ground. I don't think the slightly high readings are a problem but I'm not sure. I checked the temperature switch which was not shorted and I checked the black/yellow ground lead and it was not grounded with the ignition switch in the on position. Anyway I have no way to check the power pack but I hate to buy an expensive power pack without knowing for sure. I don't understand why the power pack would go bad just setting up for a couple months. Any suggestions out there?
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: 97 Johnson 40HP with no spark

Welcome to iboats.

Taken from the CDI Troubleshooting Guide.

Two Cylinder Engines

NO SPARK ON ANY CYLINDER:
1. Disconnect the black/yellow stop wire and retest. If the engine's ignition has spark, the stop circuit has a fault-check the key switch, harness and shift switch.

2. Check the stator and trigger resistance and DVA output as given below:

Wire Color: Check to Wire Color: Resistance: DVA Reading
Brown wire: Brown/Yellow wire: 450-550: 150V or more Connected
Black/White wire: White/Black wire: 15-42: 0.6V or more Connected

Some engines use the following wiring on the trigger:

White wire: Blue wire: 15-42: 0.6V or more Connected
White wire: Green wire: 15-42: 0.6V or more Connected

3. Check the cranking RPM. A cranking speed of less than 250-RPM will not allow the system to spark properly.

4. Check the DVA output on the orange wires from the power pack while connected to the ignition coils. You should have a reading of at least 150V or more. If the readings are low, disconnect the orange wires from the ignition coils and reconnect them to a load resistor. Retest. If the reading is now good, the ignition coil is likely bad. A continued low reading indicates a bad power pack.
 

willno

Cadet
Joined
Aug 10, 2008
Messages
13
Re: 97 Johnson 40HP with no spark

Thanks for the feed back Chris. I'll try what you have suggested as I didn't check the system as you suggest.
Bill
 
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