what should my spark look like coming from my plug?

[Dmaxx85]

I have a 1991 volvo penta 230a. and it wont run . replaced rotor, plugs, wires. The cap looked ok but not perfect haven't checked the coil, but i am getting spark from one plug should i be checking all plugs? Not sure what the spark should look like?????? Its kind of like a blue small spark and a little jumpy. Anyone think it should look different? When i turn it over it getting fuel but wont really run when i give it throttle with the starter cranking it pretty much runs and i can control the but with the starter cranking once i disengage the the motor turns right off...Any ideas ????? Help Please!!!!!!!

 

[RicardoMarine]

1. should i be checking all plugs?............
2. Its kind of like a blue small spark..........
3. and a little jumpy........
4. but with the starter cranking once i disengage the the motor turns right off...Any ideas ?

1. You can achieve this by attaching a plug wire directly into the coil, and very carefully allow an inserted spark plug to make contact with a metalic surface.... watch for any fuel vapor source! Each cylinder's "spark" will then be represented as each cylinder's spark cycle occurs.
2. Whitish-Blue is a good sign. Yellowish is not!
3. Spark being a little "jumpy" is good!
   
4. Your system may incorporate a "start by-pass" circuit that will provide a full 12 volts to the ignition coil during cranking only..... although I just looked at the 230A schematic, and I do not see this shown.

What you are describing may perhaps indicate that during cranking, you are getting power to the coil, and good spark is occuring!
But when you let go of the start mode, the ignition source quits, and the engine dies out.
IOW, while NOT cranking, voltage is not getting to the coil.

If there is a Ballast Resistor in your system, you may want to test for voltage passing through it.

Be sure that you are setting your contact points via a "dwell" meter!
Setting "gap" is an estimate only of correct dwell.


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