Help with Tachometer installation

[usraptr]

I'm in the process of installing a "Teleflex Marine" tachometer on my Mercury 4-stroke 50 HP O/B. The instructions say to set a small dial on the back of the Gage to "1/2 number of Alternator poles." Have no idea what an Alternator pole is or how many my engine has. Anybody know what I'm supposed to set the dial too? I have choices of 2P, 3P, 4P, 5P and 6P. Next to each of these "Ps" is another number. 2P has 4c next to it, 3P-6c, 4P-8c, and nothing next to 5 and 6P/ Am I to assume that the 4c would mean 4 cylinder. So since my Mercury is a 4 cylinder I would set the dial at 2P?

Also, have a question on the "send" wire to the Gage. The instructions show a diagram of a wire going from the "send" pole on the Gage to what looks like the throttle control. An arrow points to this wire and for Mercury it says "gray" so I'm assuming that is a gray wire. Off of that same "gray" wire that runs between the Gage and the throttle control is a "T" that goes to what is labeled as a "yellow" wire and then a what appears to be a wire connector block with 3 connections. One connection is labeled "Amarillo", the second is "Red" and the third is "Yellow". The yellow wire that goes to this connection forks and one end goes to the "yellow" connection and the other end goes to the "Amarillo" connection. This is all about as clear as mud. Does anybody know where I'm supposed to hook my "send" wire in plain English?

thanks in advance.
Brad

 

[Chris1956]

Re: Help with Tachometer installation

The Tachs run off the stator pulses. usually there is an application guide with the number of pulses to use by motor. I would start with the 12P setting, as that is what merc uses for it's larger motors. You will know if it is incorrect (it will idle at 400RPM, which is wrong), and can change it to 8P, 6P etc. Normally the Tach signal is the grey wire and it should be in the wiring harness at the control or under the dash. The grey wire connects to one of the yellow stator wires, under the motor hood.

The tach also needs +12V and ground to operate. Usually these are purple and black respectively. Both are avail at the control or under the dash. Merc used to have a three wire connector on the front of the control just for the tach.

 

[hkeiner]

Re: Help with Tachometer installation

The below linked guide may be helpful to you.



http://www.downloadingfiles.co.uk/t...structionmanuals/99320 rev 10 Tachometer,.pdf

 

[usraptr]

Re: Help with Tachometer installation

Chris 1956,
Thank you, I found the gray wire under the dash and spliced into it and the tach sprang to life. Ended up using the 6P position. Tried all the others and the idle was over 1000. 6P put it right at 800 which is what the manual calls for. Thanks for your help. It's greatly appreciated.

Brad