Hello, new to me old outboard that has what I beleive is weak spark..... Point are cleaned and gapped, condensers tested to spec .3 uf. Coils show 6-7k ohms from primary to end of spark boot. Kill switch completely taken out of the wiring loop to remove from the equation..I have disassembled and reassembled probably the magneto probably 4 times, regapping and cleaning points. Spark plug test light does light up and visible with garage door closed, but not bright enough flash to see in daylight. Should I be seeing very bright flash from spark bulb or are these old systems generally low voltage.
Hello, new to me old outboard that has what I beleive is weak spark..... Point are cleaned and gapped, condensers tested to spec .3 uf. Coils show 6-7k ohms from primary to end of spark boot. Kill switch completely taken out of the wiring loop to remove from the equation..I have disassembled and reassembled probably the magneto probably 4 times, regapping and cleaning points. Spark plug test light does light up and visible with garage door closed, but not bright enough flash to see in daylight. Should I be seeing very bright flash from spark bulb or are these old systems generally low voltage.
iboats Mercury | Mercury 200 series 20hp keikhaifer weak spark?
Weak spark on both leads or just one? That tells you a lot. Here's what I'd check, in this order:
1. Pull both plugs. The spec is NGK DCPR6E gapped at 0.9 mm (0.035 in). Fouled, worn or rounded plugs, or a wrong gap, can pass for weak spark. Replace them if in doubt.
2. Measure secondary resistance across the plug cap terminals with the leads and caps still attached. It should read 16.8 to 20.2 kΩ. Anything above that means the coil or lead is going.
3. If it reads high, take the caps off and measure each lead on its own. The spec is 3.0 to 7.5 kΩ. If a lead is over, replace it. If the leads are fine, the coil is the problem.
4. Check the crank position sensor. It should read 148 to 222 Ω. If it's out, the trigger signal is weak and you get a weak spark.
5. If everything above passes, check primary coil resistance, which should be 0.26 to 0.35 Ω.
Is the weak spark on both cylinders or just one?
