Sport Jet 120 - Spark Issues - Parts Install/Test Question

[Frsmith2]

Good morning.

I have a '95 Regal Rush XP with the Mercury Sport Jet 120 motor with no spark.

I had the service manual and went through all of the diagnostics. Black stator was bad. Trigger good. Flywheel good (visually).

Upgraded to the Mercury red stator kit and new rev limiter. Still no spark.

Bought a new CDI switch box and about to install it. The question I have is what is listed on the instructions, link to the pdf found here: http://www.cdielectronics.com/InstallSheet/114-6866.pdf

It says to first disconnect the kill wires, connect a DC voltmeter between the kill wires and engine ground turning the ignition switch on/off several times to see if DC voltage registers. Says battery voltage can kill the switch boxes.

Does this mean I need to disconnect the black/yellow wire from the switch box and connect the voltmeter between the wire coming to the one at the switch box and ground...or the other...or either? Does polarity (black/red) on volt meter matter? By ignition switch on/off, simply to on and not run to engage starter, correct?

Simply looking for some greater clarity before I potentially fry another switch box.

Thanks!
Frank

 

[aksor]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

Any voltage on the kill wire black/yellow will destroy new cdi. It can be due to bad ignition switch or after market ignition switch that is not meant for this type of boat. To test put voltmeter in dc voltage then connect the black wire from the voltmeter to ground any good ground on the engine disconnect black yellow wire from switchbox and attach red wire to the wire comming from the boat side not the cdi. Then have a helper go trough all positions of the ignition switch start and choke included (if you have a solenoid choke) and make sure you do not get a reading in any of those position.

To disable the starter from engaging remore yellow red wire from starter solenoid.

 

[Frsmith2]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

Thanks, that makes more sense now...I'll give it a go. I assume I'll discover any error even with the assumed bad switch box on the engine still? Meaning, the switch box doesn't have to be functioning in order for this diagnostic to work as the kill circuit is separate when unplugged?

 

[aksor]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

Correct

 

[hypersniper]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

aksor, you seem to be becoming the merc sportjet guru on here. taking over where kend left off . i have been learning alot by reading your posts and i say thank you.

 

[aksor]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

Hey guys if I can help in any way just let me know I learned a lot from this forum and its nice to help out fellow sportjet owners

 

[Frsmith2]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

Did the test today on a digital multimeter. First, tested a 1.5v AAA and 9v battery. Both good, gave me 1.xx v around 1.5 and 8.xx v around 9. Did the ignition test hoping to see zero and practically saw zero. Had a number pop up in the 100ths of 1v on the multimeter (0.04v as an example). Is this considered "voltage" for purposes of the test before I install the new cdi switchbox? Hoping not as it's only 1/400ths of 1 volt.

 

[aksor]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

The digital voltmeter is pretty sensitive it was picking up stray voltage from static. You are fine.

 

[Frsmith2]

Re: Sport Jet 120 - Spark Issues - Parts Install/Test Question

All new parts installed, original coils ohm'd perfect. Started right up and runs great in the driveway at idle (dealer flush kit installed of course). Next test will be on the water at WOT.

Next spend is addressing an intermittent starter and/or solenoid engagement. Those parts are cheap and a quick fix.

Thanks for the help.