Tachometer Problems

R

rkersh409

Petty Officer 2nd Class
Joined
Aug 19, 2006
Messages
100
I have a 1995 Evinrude 175hp motor that I just had to change out the rectifier/regulator. I thought the tach wasn't working because of the rectifier. But after changing out the rectifier it still didn't work. Tach stuck on 2000 rpm's and would not move. Went out and bought a used tach and put it on. The tach zero's out when the key is turned on. And when cranking the motor the tach goes up to about 500 rpm's. But when the motor starts it goes back to zero. I am getting 13v at the purple and 5.5v at the gray signal lead. Could it be another bad tach? Or could something else be causing it.

Thanks,
Robert
 
F

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: Tachometer Problems

Begin with a good battery, fully charged, and terminals clean and tight. Now check voltage at the battery after the motor runs awhile. Should be about 14 - 14.5 volts on a regulated system. If it is, your alternator and regulator is doing what it is supposed to do, so don't be buying those expensive parts.

Offhand, I'd say you bought somebody else's troubles when you bought that used tach. Assuming it's the correct tach for the motor.
 
E

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Tachometer Problems

Note the following part on page 4 of the installation instructions:

"1. If tachometer does not work properly on the Gray wire on engines with water cooled voltage regulator, bypass the regulator and attach to yellow/gray wire from the alternator to the rectifier."
 
R

rkersh409

Petty Officer 2nd Class
Joined
Aug 19, 2006
Messages
100
Re: Tachometer Problems

After reading that I think I have the wrong type tach. The selector switch on the back of the tach I just got only has 4, 6, 8, A, and B. I am thinking this tach should be on inboard motors. Sound right? Because I don't know if the 6 is P for poles or C for Cylinders.
 
C

canadian_fisher

Petty Officer 2nd Class
Joined
May 17, 2005
Messages
130
Re: Tachometer Problems

My 150 Evinrude had a similar problem as your 175.
In my case, the Rectififer was easy to diagnose and needed replacing. At the time, the Tach just looked at you with a blank stare.

Upon replacing the Rectifier, I only got 2000 or so RPM like you mentioned above.
Turns out the tach was cooked too.

Good Luck ........ CF
 
E

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Tachometer Problems

The six setting is correct for almost all Johnson and Evinrude motors.
 
R

rkersh409

Petty Officer 2nd Class
Joined
Aug 19, 2006
Messages
100
Re: Tachometer Problems

But just the plane ol 6 on the back of the tach means what? 6P for poles off of stator, or does it mean 6C for 6 cylinder inboard motor? Also what does the A and B stand for?
 
C

canadian_fisher

Petty Officer 2nd Class
Joined
May 17, 2005
Messages
130
Re: Tachometer Problems

Have you tried going to the Teleflex website?
Their FAQ section #1 explains the difference between 6C and 6P (inboard versus outboard).

If you cannot choose between 6C and 6P, make sure you are looking at a Tach designed for Outboards (2-stroke) and not Automotive or Inboard (4-stroke).

CF
 
R

rkersh409

Petty Officer 2nd Class
Joined
Aug 19, 2006
Messages
100
Re: Tachometer Problems

Yes I have been reading on their site. My tach does not say what kinda tach it is. It only has 4, 6, 8, A and B on the back. No P or C after any of them. I am going to assume that 4 is 4C or 2P, 6 is 6C or 3P, 8 is 8C or 4P, A is 5P and B is 6P. And since I need 6P I am going to put it on B. Thats the only thing I can make of this used tach.

Thanks for the help!
 
C

canadian_fisher

Petty Officer 2nd Class
Joined
May 17, 2005
Messages
130
Re: Tachometer Problems

Good luck........... not familiar with that style of Tach.
Looks like an automotive 4-stroke model to me.

Make sure you have a good 12Vdc and Ground to the tach along with yout Tach feed.

CF
 
You must log in or register to reply here.
Top