1958 Sea King 3 HP - no spark

[Keith M.]

Model #GG8962A: Replaced coil (18-5181), condenser (18-5199), plug wire (7mm copper core), and spark plug (NGK B6S gapped at 0.03"). Points look good and are gapped to 0.02". Electric fence voltmeter shows 2000 volts, but I do not see a spark on the plug with the plug grounded to the frame. Is this normal or do I have an ignition issue?

 

[F_R]

Electric Fence volmeter? Well that's a new one on me. But if memory serves correctly (?) spark voltage should be considerably higher than that. But I confess I've never attempted to measure it. Usual procedure is it should jump a 1/4" open air gap.

 

[F_R]

"Points lookk good" Well if you say so. But I remove them and polish each contact shiny bright and reassemble and gap them. Even new points often have an invisible non-conductive film on them.

 

[Keith M.]

I will polish the points tomorrow. The resistance is 0.1 ohms with it closed. Is it possible that the magnet is weaker, or do I just have a bad coil? I measured 10K from the high voltage lead to both primary leads, and about 1 ohm (if I remember correctly) across the primary leads.

 

[F_R]

In a perfect world, resistance across the points should be zero ohms when closed. The 10K is a bit high, but different mfrs make different windings, so don't put a lot of worry in that. I'd say the coil is fine.

EDIT: Magnets?? No way. Magnets made since WW-II just don't ever go bad.

 

[racerone]

That magneto can produce 20.000 volts or more.-----So perhaps clean the points.----Check air gap between magnets and tthe coil.-----Perhaps set the points using timing marks and a meter.-----Some fine tuning of the magneto is required here.

 

[Keith M.]

Thanks, that is good to know about the magnets and magneto voltage. What is the proper air gap between the magnets and coil, and how do you set it given that the gap is covered by the flywheel? I tried to push the coil out as far as I could without touching the magnet...

 

[F_R]

Look at the posts that the coil is mounted on. See those machined edges right below the ends of the coil's laminated core? The coil is to be moved in or out till the laminations are even with the machined edges.