Yet, another Tachometer question

Ginder75

Petty Officer 2nd Class
Joined
Apr 18, 2004
Messages
106
I have an intermediate Tachometer, works sometimes, does not work others. There is no rhymn or reason, at idle everything will be working and all of a sudden the tach drops to zero, shift into gear and everything works fine again.

I got the procedures for testing my rectifier, would a bad or dying rectifier cause this? All the connections seem tight, no corrosion. According to my new depthfinder, the charging sysem is working.

I an not real concerned about the tach, but I am trying to dial in the setup and without a real rpm number you are just guessing at performance.

Thanks for the tips,

Ginder75
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: Yet, another Tachometer question

I had a similar problem. I figured it had to be the tach. Everybody said it has to be a loose connection somewhere. I tested everything and looked high and low. Finally, I dug into the remote control. Stuff is really cramped in there so I figured something must be shorting or moving because tach readings were erratic with even minor throttle lever movement. Couldn't find a thing though. Put it all back together and it works fine. I figure it had to be in the control even though I'm too blind to see it. But I am not going to mess with it anymore as long as it works.
 

Ginder75

Petty Officer 2nd Class
Joined
Apr 18, 2004
Messages
106
Re: Yet, another Tachometer question

I completed the Ohm test on the Rectifier last night and I had reading both ways. If I did the test right, that would indicate a blown rectifier. I have noticed higher than normal voltage reading from time to time, which could also point to bad rectifier.

So, next question - My boat has a five wire rectifer. My parts supplier shows a four wire rectifier for my motor. What is the difference? Can a four wire work in place of a five wire? Should I keep looking for a five wire?

Thanks guys,

By the way - It is a 1992 Johnson 115, with tilt, trim, electric start, and it was VRO equiped. And it is Long shafted. Sorry, I left the model number at home.

Robert
 
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