Kevin,

I have a question in regards to wiring my boat tachometer. I have a 1973 135Hp Johnson outboard V4 on a 1970 Glastron and the tachometer is not working simply because it’s not connected to the rest of the boat wiring.

So where do I start..? I’ll run all new wires, but to what? And how many wire leads will I need? Do I wire it into the throttle box, if so, to the ignition switch and how or do I have to run a set of wires to the motor directly?

Thank you,

Russ

Russ,

All the required wires should already be at your ignition switch/throttle box.

• Purple – Switched power from Key switch – Connect to B+ on your tachometer
• Gray – Tach signal – Connect to the S on your tachometer
• Black – Gauge ground – connect to the (-) on your tachometer

Hope this helps,

Kevin

Kevin,

Thank you kindly; you’re really prompt and it’s appreciated.  I can’t wait to get back under the dash and look for those contacts on the tach. 

Funny, I just had to replace my throttle cables last weekend (it snapped just past the no wake zone; not good, however we couldn’t dare tell our 4 and 5 year old boys that the party was over.  They were so excited to be on the boat for their first time, so we came up with a plan; my wife steered as I sat in the back with the motor and cables pushing and pulling on them until we got it down pretty good and off we went to finish out the fishing adventure; had a great day anyway) and I had the throttle box completely apart.  And so at the same time you just solved the two dangling wire mystery from below my throttle box. 

I look forward to opening the throttle box back open and hooking it up right and actually seeing the tach operable.  I’ll keep you posted and if I run into any other problems or question I’ll reach out again; great website…

Thank you again Kevin and sorry for that long story, but I couldn’t help it we are first time boaters and having a ball.

Russ