Boat gauges questions. how to...

ritamigo

Seaman
Joined
Mar 16, 2012
Messages
62
I have a Hydra sport 1993 15.6 ft and I had to replace the dash. Now the tachometer needle cam off (I dropped it).

QUESTION TACH:[/B][/B] I re-attached it and the setting in back was set on 5 cylinders. There is a setting for 3 cylinders. I have a Johnson 70 hp 3 cylinders. I am sure it was like that since new. It idles at about 1900. How will I know which setting is correct? And if I buy a universal one, is the connection universal too? Like sender, neg and positive? (I know, one for light).

QUESTION VOLTMETER: The voltmeter is now reading on 8 volts when it should be over 12. It also has 3 connections, sender. neg and positive (and one for light). Why 3?. How do I connect a new one if I have to and how to check to see if the gauge is bad. I do get the right reading when I bench test it.

BTW, I eliminated the speedometer, it really was useless, it went to 80 and I could only reach 22 at best because of space issues where i fish. Any thoughts?

Thanks again for help and guidance...

JoeVee
 

JoLin

Vice Admiral
Joined
Aug 18, 2007
Messages
5,146
Re: Boat gauges questions. how to...

The tachometer setting 'numbers' don't represent the number of cylinders in the engine. Johnson/Evinrude motors have a specific setting- I think it's '6' but don't trust my memory. Somebody else will know for sure.

Speedometer- thoughts on what? A GPS, including the portable one out of your car, will tell you your speed over the bottom.

Sorry, can't answer the rest of your questions. Others will be along...
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,269
Re: Boat gauges questions. how to...

all tachometers sold in boats are universal. first off, you can put the needle back on, just make sure you put it on in during a known run condition - such as key on engine off so that the core motor is at 0.

then depending on the tach and your ignition system, you will need either 3 cylinder or 6 cylinder setting for your 3 cylinder tach.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Boat gauges questions. how to...

The calibration dial for outboards is not related to the number of cylinders an engine has but rather the alternator output. It relates to the number of poles and pulses the alternator delivers. A 12 pole alternator delivers 6 pules to the "sense" wire feeding the tach. that's what your engine delivers so the dial needs to be set to 6P. The voltmeter has a "S" (sense) terminal only because the same gauge housing is used for all gauges of that series. For a voltmeter that terminal is not used (in fact it connects to nothing inside the gauge).
 

ritamigo

Seaman
Joined
Mar 16, 2012
Messages
62
Re: Boat gauges questions. how to...

Silvertip thanks for the tip!!!! Appreciate it.

JoeVee
 
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