How to test stator?

Took the boat out today for the first time this year. It is a 1986 model year 90 hp v4 Johnson two stroke.

After driving a few minutes I saw the tachometer wasn't working. We continued for a few more minutes, then I slowed down and once it was in neutral before shutting the motor off the tach started working. Upon starting the motor back up after sitting for a half hour it worked right away and for the approx two miles back to the landing. The motor ran like a top the whole time even when tach wasn't working.

I replaced the regulator/rectifier in 2018 and it has maybe at most 20 hours on it (don't use boat much). At the time the tach didn't work at all (not intermittent), which makes me think stator is possibly going bad now. I also replaced gauges in 2018.

I am going to track the tach functionality in future outings, but in the meantime would like to test the stator. I have a voltmeter and DVA adapter but have no idea how to test.

Any advice appreciated on testing or other thoughts on the problem.

Just 2 tests.-----First an ohm reading on the 2 yellow wires.-----Then from JUST 1 of the yellow wires to ground.-----Post those 2 numbers.

Ok so I just hooked up the multimeter.

Two yellow wires: 0 to 0.1 ohms (continuity)
One yellow to ground: no continuity (my meter is a digital Kobalt that autoscales and shows L0 for high ohms)

For the ground I used one of the unpainted bolt heads securing one of the coils. Tried with both yellows, same results.

I think I used the correct yellow wires. Two come out from a connector under the flywheel. These are the two I used. Two also come off the regulator/rectifier. I unscrewed the screws and unsecured the wires so I was only testing the ones from under the flywheel.

Did I do it correctly?


I read ohms readings don't always tell the whole story. How do I test using a DVA?

Thanks for the input. I can switch out parts but am new to diagnostics.

Are you sure the problem isn't in the (+) and (-) power supply wires to the tach? Is it a plug-in tach? Check the plug connections for corrosion.

Um...You did remove and clean the battery cables terminals, didn't you?

Are the ohm values from the stator what they should be?

The tach connections look ok (tight and not corroded). The battery is a PITA to access but I will check the connections and terminals later today.

Battery terminals clean and tight (battery only a year and half old).

Do the ohm readings from the stator (yellow to yellow 0 ohms, yellow to ground infinite ohms) mean it is ok?

I turned the key to accessory this afternoon while cleaning the interior and the tach did move.