No RPM reading on tach

[tutt]

1994 115hp merc. Motor runs fine. Tach stopped working about a month ago. (No voltmeter installed) Starting battery is a Die-Hard Starting/deep cycle, about 9 months old, but needs a charge each time I come off the water now. This battery also runs all electronics less trolling motor. (livewells, depth/fishfinders, lights). Stator failed last fall and was replaced. Tach was "jumpy" and mechanic replaced it. Worked fine until now. <br /><br />on a related issue, is the battery too large? 27M 600CCA I think? Should I get an onboard charger to charge the Starting and trolling motor batteries?

 

[Robot19]

Re: No RPM reading on tach

Could be a bad voltage regulator.

 

[The Marine Doctor]

Re: No RPM reading on tach

Grey wire supplies signal to the Tach....Yellow wires supply current from the Stator to charge the battery.<br /><br />Both are common to the same part...The Voltage regulator which also only lets the current go one way Now two ways..which is draining your battery.<br /><br />As said above..the voltage regulator<br /><br />TMD

 

[CARLOS]

Re: No RPM reading on tach

HI MARINE DOCTOR,<br /><br />I´M NOT CLEAR ABOUT YOUR EXPLANATION. YOU DID MEANS THAT THE CURRENT GO TO THE BATTERY AND TO THE TACHOMETER AT THE SAME TIME?<br />DO YOU HAVE ANY CHART OR PICTURE HOW TO UNDERSTAND THE CURRENT FLOW INSIDE VOLT. REGULATOR.<br />MINE IS A 3.4L MARINER. ONLY ONE REGULATOR 40 AMP.<br /><br />SALUDOS DESDE VENEZUELA<br /><br />CARLOS SCHEMEL

 

[tutt]

Re: No RPM reading on tach

Searching town for a voltage regulator today.

 

[The Marine Doctor]

Re: No RPM reading on tach

The tach recieves its pulse within the Regulator from the yellow wires. Its transfered to the grey wire also within the regulator...then sent up to the Tach.<br /><br />TMD

 

[MercBassmaster]

Re: No RPM reading on tach

Just had same problem with my 135 - it's most likely going to be the rectifier - the tach receives signal from rectifier - should be fairly inexpensive, think I paid about $30 for mine and it fixed the problem.

 

[tutt]

Re: No RPM reading on tach

Pulled off the voltage regulator and the circuit board looked more like a piece of charcoal. (At least a section of it)<br />Now I'm a bit scared about what might have caused that kind of damage.\<br /><br />Maybe I'm asking too much of the charging system? <br /><br />My trolling motor runs on a seperate battery, not connected to the engine. My starting battery is a 27M Starting/deep cycle combo by Die-Hard and rund all other electronics livewells,depth finders, lights..) <br /><br />I haven't been charging this battery when I leave the water, is that a mistake? Should I buy a seperate starting battery and run the electronics off the deep cycle? Will charging this one each time I come off the water solve the problem?<br /><br />I couldn't find a requlator around town for less then $120 and don't want to repeat the problem.