Tach help

[rocketman87]

I need help trying to figure out why my tach doesnt work...I have a 2002 mercury by tracker 25 hp on a bass tracker pt165.....any help where to start would be appreciated.............the wires on the back of tha tach seem clean and tight........not sure where it reads from on the motor.............

 

[Barnacle_Bill]

Re: Tach help

Need a little more info. Is the motor electric start? Did the tach ever work? Many times they fail because someone hooked up the battery backwards for a second or caused a spark somewhere and blew the rectifier and or regulator.

 

[rocketman87]

Re: Tach help

Electric start /remote . Dont know if it ever worked.........did not work when I bought it used 6 months ago...............In fact I dont know if it worked when it was new or even if they hook up the tach on the mercury 25hp.........I assume it worked at one time because there are wires on the tach on the back.......but that may be just a factory rigging and maybe they dont even hook up the tachs on the mercury 25's...........if anyone knows or knows how I can find out please help me.........thanks again

 

[Barnacle_Bill]

Re: Tach help

Look on the back of the tach. There should be a minimum of 3 wires hooked up. Black to ground, Power, usually from the switch, and a gray wire which is the tach input. If they are there check your charging system. Check the voltage at the battery with the key off. Now start the motor (in the water or muffs) and you should see a slight increase in voltage if its working properly. You won't see much of an increase until the motor approaches 2K RPMs.

 

[rocketman87]

Re: Tach help

Hey thanks bhile........


I keep my boat inside at storage and it is 1 hr away...so I am trying to get all my info so when I go back I can try everything.......It is not as simple as going out to the garage........so having said that.......


If the voltage increases then whats next or if it doesnt increase then what........I really appreciate the help..........

 

[Barnacle_Bill]

Re: Tach help

If your charging circuit is working properly and the tach is hooked up properly then chances are you have a bad tach. If not then you need to find out why. Either a bad rectifier/regulator (most common cause) or a bad stator.

 

[rocketman87]

Re: Tach help

Is it safe in assuming when this boat left the factory the tach was hooked up and working ??? Just making sure they hooked up tach's on the 25hp motors...........

 

[hkeiner]

Re: Tach help

Attached below is a tach troubleshooting guide. This guide along with a multimeter should help you determine if the problem is with the gauge, the rectifier/regulator on the motor, or the wiring in between. I suggest not replacing a part until you confirm that it is defective.

Good luck