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Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 11050
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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I have a 76 Crestliner apollo 660 and need wiring info tach

Customer Question

Hello I have a 76 Crestliner apollo 660 and need wiring info for the tach and fuel sending unit systems
Submitted: 1 year ago.
Category: Boat
Expert:  Tan replied 1 year ago.

Hello. My name is Tan.

The fuel sending unit is a pink sender wire and a black ground coming from the fuel sending unit. The tach wiring will be a purple, black and a gray wire coming from the remote control of the engine harness for the key switch.

Now I don't no if you have the key switch in the remote control or the dash.

What elese can I help you with. This is the basic for getting started post back if you need further explanation. Let me know what you are looking for if other than what I have provided.

Customer: replied 1 year ago.
The original wiring was cut out by the previous owner and he made a bad attempt at reasonable wiring it that is why I need diagrams to see how it should be hooked up
Expert:  Tan replied 1 year ago.

There are no diagrams and never was. These boats were wired by individuals from the factory and they did not use diagrams to follow.

The wiring for the tach is already in the wiring harness with the engine. For the fuel tank sender all you have to do is run 2 wires from the dash to the fuel sending unit pink and a black. Pink goes to the sender terminal center of sender, black to one of the screws holding the sender in the tank. On the gauge pink to S terminal Black to G terminal and the Pink to the S terminal of the gauge. Run a purple from the tach and a Black from the tach. Connect purple to I terminal on fuel gauge and the black to the G terminal of the gauge. Very simple.

Why do you need a diagram to run 2 wires and the wiring for the tach is already in the engine wiring harness coming from the engine.

To wire the tach all you need are the purple connecting to the I terminal on tach, black wire to G terminal and the Gray wire to the S terminal on the tach.

Now I have no idea what you have as far as the key switch goes is it in the dash or in the remote control?

Expert:  Tan replied 1 year ago.
Customer: replied 1 year ago.
Well that is a lot more helpfull just telling me colors don't help when there is no wiring in the boat. And the key is in the evenrude control set up
Expert:  Tan replied 1 year ago.

Good luck.

Customer: replied 1 year ago.
You are very rude and unprofessional. I never said running two wires is a difficult thing to do, but when you just say that the wires are this color as you did in the first comment your giving me worthless info when the wires are gone. That is why I asked a out a diagram. In your next post you told me HOW they are to be wired that is actually useful info that I can use to read wire the boat.
Expert:  Tan replied 1 year ago.

You didn't tell me the wires were gone. This was your statement. "Hello I have a 76 Crestliner apollo 660 and need wiring info for the tach and fuel sending unit systems"

Customer: replied 1 year ago.
Why would anyone need a diagram if the worse were still there. It's a two wire system. But when you have no wires it's hard to know what they are to be hooked to
Expert:  Tan replied 1 year ago.

Most people ask for a wiring diagram so they know how the wires connect to components. I just can't assume every boat a person works on has no wiring in it. Many times people ask for wiring diagrams because the boat wiring is all messed up.

When a customer asks for a wiring diagram on a boat that's 40 years old I have no idea what you are dealing with after 40 years. You have to give me info that helps me understand what you are dealing with. I have worked on thousands of boats and all are different.

I'm sorry I wasn't trying to be rude. Just don't know everything about all boats and what each customer is dealing with.

Customer: replied 1 year ago.
There is a fourth blue wire running from the tach? I don't know it the tach is back light or not would that be a power wire for back lighting?
Expert:  Tan replied 1 year ago.

Correct that is for the lights in the gauges. This can be connected to the I terminal on gauge or the navigation light switch. I always connected it to the I terminal so lights will be on all the time. This also dries out any moisture in the gauges that can cause fogging of the lens.