1988 75hp mariner No spark please help!!!

[jonj200369]

I have what I believe to be a 1988 75hp 3cy 2stroke mariner outboard the serial number is "Da743780"

The motor ran great for a number of years, I was at the lake one day towing a tuber and I hit a crazy wake and put my boat on a 90 degree angel(On its side)
the motor instantly died and the boat righted it self and then the engine would not start. I limped home on my kicker and brought the boat home. The next day I turned the key a couple times and it started for a brief second, so I shut if off and thought I will come back when I have more time. I came back a week later and the engine will not start.

I'm about 99% percent sure its getting fuel. I pulled the plugs and was able to determine that none of the three cylinders are getting any spark whatsoever

Anyone have any ideas?

 

[CharlieB]

Re: 1988 75hp mariner No spark please help!!!

Follow the black wire with the yellow trace from the ignition switchbox, it goes into the main harness to the ignition switch and lanyard, grounding this kills the ignition. Many models 'T' into this wire at/on the motor and connect to a small lipstick sized plastic housing, containing a grounding switch that kills the motor once the craft is turned over. Sometimes this switch sticks or just grounds out. Disconnect it and retest for spark.

If still no spark, disconnect the switchbox black w/Yellow from the harness and retest again, you could have a poor ignition switch, or lanyard, grounding.

 

[jonj200369]

Re: 1988 75hp mariner No spark please help!!!

Thank you for your reply. Last night I attempted again to get her running, I removed the blk/yel kill switch wire to no avail. One thing I did notice however was there there was intermittently spark on all 3 cylinders, but it seemed rather weak when it was present. Using a multi-meter I was able to determine that where the plug wires join the coil? there is no power present during ignition. I found this rather strange.

 

[CharlieB]

Re: 1988 75hp mariner No spark please help!!!

Once you learn the function of each component of your ignition system it is quite simple, expensive parts, but simple in theory.

Download and study the free Outboard Ignition Troubleshooting Guide from CDI Electronics.

Get a DVA meter and perform a few simple test spelled out in the guide, that will show you exactly what your problem is.

Make double sure that your battery is fully charged, ALL cable connections are shiny clean and tight, BOTH ENDS. The ignition has a minimum cranking speed of 300 RPM, any less can result in no or a weakened spark.

 

[jonj200369]

Re: 1988 75hp mariner No spark please help!!!

Turns out it was the stator. I got one used for 250$
problem solved