NS90a only gets spark half the time.

[keith317]

I bought a flats boat about a year ago with a 90hp Nissan on it (ns90a). The problem I'm having is that it isn't getting a spark some of the time. I have had a few mornings where I would try to get it started for an hour before it would start. Once it is running it's fine for the rest of the day and starts up every time. After it sits in the driveway for a few days it will go back to not getting a spark. ive disabled the kill switch to see if that made a difference and I've tested the spark plug wires. Has anyone else had an issue like this.

 

[Sea Rider]

Welcome to Iboats,

Are all electrical components grounds immaculate clean and shinny state cond, including having good ground contact with crankcase ? Are plug caps shinny, that's non corroded ? How about installing new plugs, probably one is defective or with electrical issues. If that model has independent ignition coils, probably the one that misses badly is already with electrical issues, one step prior becoming completely shot.

Happy Boating

 

[keith317]

Grounds look clean, spark plug wire caps aren't shiny so I'll clean them up. Spark plugs are new. None of the plugs have any spark.

Thanks

 

[Sea Rider]

All plugs have independent Ignition Coils ? Or it's a dual CD, Ignition Coil pack ?

Happy Boating

 

[keith317]

All the plugs have independent coils and one CD unit.

 

[Sea Rider]

Is that symptom only achieved on all plugs at same time, or it's an individual plug issue ? Is your exciter coil located under flywheel in good operating mode ? If with electrical issues could achieve erratic CD misbehaving operation.

Happy Boating

 

[keith317]

Either all the plugs fire and the outboard runs perfect or none of them fire and it doesn't run. Once I get it running, it starts up and runs fine for the rest of the day. I will look under the fly wheel tomorrow to see if the connections are good. How can I tell if the exciter coil is bad, can it be tested somehow with a volt meter.

 

[Sea Rider]

Testing electrical components is tricky specially if overheating, when cold or at temp engine runs fine, when overheats shorts, cuts or whatever is doing shuts engine down. When cold will start engine again and die soon afterwords when heated. Will need to measure it while cold with a non digital ohm meter, that's when cold and when supposedly fails, same for CD.

Strange once is running operates throughout the whole day with no issue. Clean all grounds and check are well tight to crankcase. Let me check later if can get the tech specs for you.

Happy Boating

 

[Sea Rider]

Nissan/Tohatsu 2 strokes 90 HP Specs :

Exciter Coil Output (Cranking)
8.1 - 9.9 DVA (WHITE/GREEN to BROWN/WHITE)
34.2 - 41.8 DVA (WHITE/GREEN to WHITE/YELLOW)
35.1 - 42.9 DVA (BROWN/WHITE to WHITE/YELLOW)

CD Unit Output (Cranking)
198 - 220 DVA

Pulser Coil Output (Cranking)
4.75 - 5.0 DVA (minimum 3.0 DVA)

Although when cold could have those spcs, when hot is other story, will need to start measuring each component as soon engine fails to check its electrical alterations with respect when cold. Need a instrument that has DVA capabilities like :

Analog Multimeter,
Electronic Specialties Model / M-530 or equivalent

Digital Multimeter,
Electronic Specialties Model / KD 3200 or equivalent

Happy Boating