How do I hook up a Tach on 15R75C Johnson.

[Xeenan]

I was researching boat props and found out I have to use a tach to test my WOT to test the pitch of the blade, but I dont have a 2 cycle tach nor do I know where to hook it. Its not like my car where I have a green tach wire. lol

 

[Joe Reeves]

Re: How do I hook up a Tach on 15R75C Johnson.

You need a tach that operates off of the engine's 6 pulse charging system. The tach will have a gray wire that attaches to the rectifier's yellow/gray wire terminal.

 

[Xeenan]

Re: How do I hook up a Tach on 15R75C Johnson.

I dont have a charging system. It is rope start

 

[jay_merrill]

Re: How do I hook up a Tach on 15R75C Johnson.

Tiny Tach. Be sure to order the two stroke engine version.

http://www.tinytach.com/tinytach/index.php

 

[F_R]

Re: How do I hook up a Tach on 15R75C Johnson.

In that case, you need an inductive tach. It will have a clamp that you snap onto a spark plug wire. Many shop tachs are that way. Or a tinytach.com

It might make more sense to get a prop dealer to set it up, rather than spend money on a tach and start buying props that might not work.

Third option is to guess at it, using a prop chart. 99.9% of small boats are set up that way.

 

[Joe Reeves]

Re: How do I hook up a Tach on 15R75C Johnson.

Yep, on a rope start, what Jay & F_R said.

 

[Xeenan]

Re: How do I hook up a Tach on 15R75C Johnson.

Cool thx for the answers guys, Ill look into it.