Tach not working

[wanagofass]

Its an 89' evinrude 150 has good power and ground but doesn't work, what should I check and what setting should the guage be on pulse wise?

[EMDSAPMGR]

The arrow on the back of a marine tach should be pointing to 6. The tach gets it's signal from the grey wire at the control box, (also the hot and ground.) The charging side of the stator generates pulses each time the flywheel rotates. It sends a charge to the battery through the rectifier/regulator, and also feeds the tach signal through the yellow/gray tracer wire at the rectifier regulator. That wire becomes the grey tach signal lead at the control box. You could have a bad tach, or you may have a bad rectifier/regulator. If the voltmeter seems to start out around 12.5 and eventually charges up to the 13.5 or slightly higher, your rectifier regulator may be ok. Generally, if the charging system is unable to replenish the battery, (voltage stays around 12.5 or lower) the tach may wind up not working. That could be either a bad stator or a bad rectifier regulator-both of which are pretty expensive.

[bigbluechevy454]

The arrow on the back of a marine tach should be pointing to 6. The tach gets it's signal from the grey wire at the control box, (also the hot and ground.) The charging side of the stator generates pulses each time the flywheel rotates. It sends a charge to the battery through the rectifier/regulator, and also feeds the tach signal through the yellow/gray tracer wire at the rectifier regulator. That wire becomes the grey tach signal lead at the control box. You could have a bad tach, or you may have a bad rectifier/regulator. If the voltmeter seems to start out around 12.5 and eventually charges up to the 13.5 or slightly higher, your rectifier regulator may be ok. Generally, if the charging system is unable to replenish the battery, (voltage stays around 12.5 or lower) the tach may wind up not working. That could be either a bad stator or a bad rectifier regulator-both of which are pretty expensive.
i agree

[klem]

Is this true for mercury tach also?

[wanagofass]

The arrow on the back of a marine tach should be pointing to 6. The tach gets it's signal from the grey wire at the control box, (also the hot and ground.) The charging side of the stator generates pulses each time the flywheel rotates. It sends a charge to the battery through the rectifier/regulator, and also feeds the tach signal through the yellow/gray tracer wire at the rectifier regulator. That wire becomes the grey tach signal lead at the control box. You could have a bad tach, or you may have a bad rectifier/regulator. If the voltmeter seems to start out around 12.5 and eventually charges up to the 13.5 or slightly higher, your rectifier regulator may be ok. Generally, if the charging system is unable to replenish the battery, (voltage stays around 12.5 or lower) the tach may wind up not working. That could be either a bad stator or a bad rectifier regulator-both of which are pretty expensive.
So what voltage should I see at the gray wire if everything is working properly?12.5-13.5v or did I misunderstand you? Everything else seems to work fine on the motor and the battery has been holding a charge w/out disconnecting for about a year w/lots of starts and short runs.

[EMDSAPMGR]

The 13.5 volts is a dash-mounted voltmeter reading indicating battery charge after the engine has been running for 15-20 minutes. The factory service manual has a series of tests which can be perfomed on the stator, rectfier/regulator. To test the tach signal lead you must have a special "peak-reading" voltmeter, which most folks don't have. With the engine running at 1000 rpm, the peak reading voltmeter should read 9 +-1 volts at the grey wire.

[perfmarine1]

I have been told from kysor medallion before they went out of business you can use a volt meter set to Hz to check the pulse line (gray wire) and it should reed 70 Hz for 700 rpm,120 Hz for 1200 rpm and so on. This does work on omc most of the time,I have done it many times. Red lead to gray wire black lead to ground.

[wanagofass]

I have been told from kysor medallion before they went out of business you can use a volt meter set to Hz to check the pulse line (gray wire) and it should reed 70 Hz for 700 rpm,120 Hz for 1200 rpm and so on. This does work on omc most of the time,I have done it many times. Red lead to gray wire black lead to ground.
Thank you, that is exactly what I was wondering, just wanted to check for signal before I drop the cash for a new tach.

[wanagofass]

Could the purple wire at the regulator not getting a 12v signal back from the ignition switch cause the gray tach signal wire to loose it's signal?

[racer]

Yes, if your regulator has a purple lead it needs 12 volts when the key is turned on, without it the regulator will not turn on.