1980 Mariner 115 Gauge addition question.

[scottybm1]

I have a 1980 Jetster 17' runabout/ski boat. It's in awesome original condition, I bought it from the original owner who took excellent care of it. The only gauge it has is a speedo. I want to add a tach, temp, water pressure and maybe volt meter. Can anyone tell me how easy it's going to be to wire these up? I can mount them easy, it's just cutting and bolting in. My question is does the motor have the senders already or is it an easy addition? I'm in the Coast Guard but I'm a small boat operator, not a fixer. Thanks in advance,
Scotty

 

[Chris1956]

Re: 1980 Mariner 115 Gauge addition question.

Water temp gauge is of no use, as the motor has no thermostat. Water pressure gauge is a good idea. Find the telltale fitting on the cylinder head water jacket cover. Replace the plastic elbow with a tee, and install the elbow and gauge nipple.

Tach normally has a three connector rubber plug on the front of the MerControl. Black is ground, red is +12VDC and the third wire (brown or grey) is tach signal. Use the 12P setting on the tach.

Voltmeter may be connected to any gauge's +12VDC and ground source.

 

[scottybm1]

Re: 1980 Mariner 115 Gauge addition question.

Water temp gauge is of no use, as the motor has no thermostat. Water pressure gauge is a good idea. Find the telltale fitting on the cylinder head water jacket cover. Replace the plastic elbow with a tee, and install the elbow and gauge nipple.

Tach normally has a three connector rubber plug on the front of the MerControl. Black is ground, red is +12VDC and the third wire (brown or grey) is tach signal. Use the 12P setting on the tach.

Voltmeter may be connected to any gauge's +12VDC and ground source.

Thank you!
This is great information.

 

[scottybm1]

Re: 1980 Mariner 115 Gauge addition question.

I just thought of one additional question, what range should I look for on the Tach? I've seen from 0-5000 RPM, 0-6000, what is the operating range of the 6 cylinder tower of power?
Thanks again,
Scotty

 

[Chris1956]

Re: 1980 Mariner 115 Gauge addition question.

You will likely run that one about 5.8K - 6K. If you can find a 0-7K Tach that would be ideal. If not, a 6K one will work.

 

[scottybm1]

Re: 1980 Mariner 115 Gauge addition question.

Does it have to be a marine tach or will an automotive one work? I have an old autometer tach from my VW days that has a 4-6-8 cylinder switch. All it needs is power, ground and a signal from the ignition. I'd like to put the right one in but for now I could run this one for free!