Motor is a 1985 model year 90 hp v4 Johnson two stroke.
Took boat out today and when it was idling and when I was going very slow after putting it the water the tach worked. After leaving the dock starting to accelerate it dropped to zero. Speed was about 5 mph. As I sped up more to 10-15 mph it started fluctuating all over the place (between zero and about 3k rpm).
After a couple minutes I sped up more and leveled out around 25mph and the tach worked fine (around 3k rpm). Drove about 5 more minutes with it working and stopped for a half hour. Upon starting it up the tach worked for the 10 min drive back to the dock.
This was only the second time out this year, and it behaved this way both times. The motor ran like a top the whole time.
I would like to test the regulator/rectifier, stator, and tach itself. I have a voltmeter and DVA adapter but have no idea how to actually conduct the tests for these components.
The battery and battery connections are good. The connections to the tach seem good.
Any advice appreciated on testing or other thoughts on the problem.
Took boat out today and when it was idling and when I was going very slow after putting it the water the tach worked. After leaving the dock starting to accelerate it dropped to zero. Speed was about 5 mph. As I sped up more to 10-15 mph it started fluctuating all over the place (between zero and about 3k rpm).
After a couple minutes I sped up more and leveled out around 25mph and the tach worked fine (around 3k rpm). Drove about 5 more minutes with it working and stopped for a half hour. Upon starting it up the tach worked for the 10 min drive back to the dock.
This was only the second time out this year, and it behaved this way both times. The motor ran like a top the whole time.
I would like to test the regulator/rectifier, stator, and tach itself. I have a voltmeter and DVA adapter but have no idea how to actually conduct the tests for these components.
The battery and battery connections are good. The connections to the tach seem good.
Any advice appreciated on testing or other thoughts on the problem.
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