1985 25hp elec start evinrude pulse

[blairham]

I have a 1985, 2 cylinder, 25hp elec start evinrude that I am trying to attach a tach to.

I have a Teleflex tach, 0 -- 7k with digital hour display. the face shows "teleflex 2002". the back of the tach has 3 connection poles; one each for send, ign and ground, with a 4th at the top for light. it also has a dial to rotate based on the number of cylinders and pulses.

I connected the ignition, ground and send (gray wire from harness). I don't know what setting the cyl/pulse should be set to. What pulse setting should i set this tach to in order to get a tach reading?

when i turn the ignition on the dial zeros out and the digital display appears, but no tach reading.

the tach was used to me, so i don't have installation instructions.

thanks for any help.

 

[Joe Reeves]

Re: 1985 25hp elec start evinrude pulse

Normally the tachometer would be set to number six (6). The majority of the OMC engines emit 6 pulses from the charging system and the tachometers operate off of those pulses.

I'm assuming you engine has a charging system?

 

[blairham]

Re: 1985 25hp elec start evinrude pulse

I couldn't tell you. how would I know?

I'm completely new to the boat/outboard experience.

 

[Joe Reeves]

Re: 1985 25hp elec start evinrude pulse

Look for a charging rectifier as follows.

(Small Rectifier Description & Location)
(J. Reeves)

On most 2,3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.

The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high. The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:

One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.

Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue