76 Johnson 70hp

knouse94

Petty Officer 3rd Class
Joined
Aug 28, 2010
Messages
88
Ok, I used to have a Merc 500 and scraped that junker for this Johnson. I just need to know where to put my fitting for my water pressure gauge and the send wire for my tach. Thanks
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 76 Johnson 70hp

I don't think that engine came with a tell-tale, you could install one and the tee off of it for your pressure guage. There should be a gray wire in the control harness for your tach.
 

knouse94

Petty Officer 3rd Class
Joined
Aug 28, 2010
Messages
88
Re: 76 Johnson 70hp

I am not really sure what you are talking about. Do I just install it near the spark plugs where I did on my old Merc? I am new to boating so I am not familiar with some of the terms. On my old Merc I just took a 3/8" plug out that was right next to a spark plug and installed the fitting that connected to my hose for the gauge.
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 76 Johnson 70hp

An engine that did not come with a tell-tale on it has to be drilled and tapped to convert it. It should be installed on the top of the block or cylinder head. If you do a search you will find posts on how to do it.
 

knouse94

Petty Officer 3rd Class
Joined
Aug 28, 2010
Messages
88
Re: 76 Johnson 70hp

Just got around to doing this and just want to clarify. So do I just splice into the gray with and connect it to the sender of the tach? Thanks
 

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: 76 Johnson 70hp

Yep. I added a tach to my '73 and there was a gray wire in the control box I just connected it to.
 
Top