tach?

[david_r]

i got another boat and the back of the tach says : pul/rev 2 - 3 - 4 - 6 - H

i have a '79 johnson 115tl79r what setting do i need?

 

[david_r]

Re: tach?

my research shows 6. if this is not correct someone please tell me.

another question is will it work without a rec/reg?

i have found conflicting opinions -------some say yes some say no.

 

[jonesg]

Re: tach?

Usually a wild tach indicates a bad regulator or wiring.
I think the tach reads the rectified pulses, so no rec/reg means no tach.
You need to post more info, what have you done and what is it doing.

Not certain but I think 4 cylinders are set to 6 on the tach.

 

[david_r]

Re: tach?

ok heres what i did:

did some core samples on my old boat transom---rotten.

so igot another boat.

this boat has matching gauges and i was wanting to keep it that way.

on my old gauge all my markings were gone......like someone did it purposefully.

my new gauge didnt work so i hooked up my old gauge......same thing....no work.

i ran some tests on my reg/rec and it is bad.

did this knock out my old and new tach?

it seems like i read that a bad rec would kill your tach.......and if it reads the charging system shouldnt it still read it since the wire is hooked to the charging system at the wire bar?

 

[Barnacle_Bill]

Re: tach?

Your tach works off an AC pulse from the stator. You can take the rectifier/regulator out and throw it away and as long as the tach is connected to one of the yellow wires coming from the stator, it will work (if the stator is good). The connection for the tach is made at the rectifier/regulator simply because it is a convenient place to make it. The 2 yellow wires coming from the stator feed a full wave bridge rectifier consisting of 4 (sometimes 6) diodes. It depends on which diode gets damaged whether it will affect the tach or not. Bottom line is the charging system can be damaged but the tach still work