1979 Johnson 115 HP Tach Question

[OFD56]

Hello I am wondering if it is possible to put a tach on my 1979 Johnson 115HP. And if so where I would connect the wires to at the motor. Thanks in advance

 

[KYHunter2]

Re: 1979 Johnson 115 HP Tach Question

Yes, you really should have one.<br /> The wires you need to connect to ,should be in the remote control. Grey is tach signal from rectifier, black is ground and red is hot for the light. If you have other guages you can get the hot from one of them and ground at fuse panel . <br /> Depending on the tach you buy, most come with wiring directions. <br /> KYhunter

 

[ezeke]

Re: 1979 Johnson 115 HP Tach Question

If you have the original control, the wiring for the tach is in place. It is located on a three hole plug below the ignition key. <br /><br />To use it you need a wiring harness and a tach which you can get from your Johnson/Evinrude dealer. <br /><br />Sometimes the pulse lead (grey wire)is taped off inside the control but it is simple to connect and instructions come with the tach.

 

[OFD56]

Re: 1979 Johnson 115 HP Tach Question

Ok thanks guys I will buy one and put it in asap. Also I am wondering do these older motors have a charging system for the battery while the motor is running similar to a altenator?

 

[ezeke]

Re: 1979 Johnson 115 HP Tach Question

Yes, they have a unregulated rectifier. It uses diodes to convert alternating current to direct current for recharging the battery and providing a small amount of 12 volt direct current for the helm through the control. Look for a triangular base with a protruding cylinder and three or four wires. Click here, Looks like this one

 

[OFD56]

Re: 1979 Johnson 115 HP Tach Question

Ok thanks very much

 

[OFD56]

Re: 1979 Johnson 115 HP Tach Question

Ok do you know how much charge the rectifier gives the battery, will it keep the battery maintained? I am just wondering how often I should charge the battery, this is my first electric start outboard, and I bought a really nice battery for it and don't want it to get ruined.

 

[emdsapmgr]

Re: 1979 Johnson 115 HP Tach Question

If you have power trim, you have a 10 amp stator, if not, it is a 6 amp. While this is not a lot of charge, it should keep your battery up with no further charging. Note that the engine has no voltage regulator and will keep charging, even if the battery is fully charged. On long runs it is possible to overcharge, so keep an eye on the battery water level throughout the boating season.

 

[OFD56]

Re: 1979 Johnson 115 HP Tach Question

Ok so it would probably be in my best interest to install a voltage meter for the battery to watch the charge?

 

[KYHunter2]

Re: 1979 Johnson 115 HP Tach Question

Its a good idea , I guess. I have had a meter on boats. And I've had them without.<br /> <br /><br /> I've never had a problem with overcharge. <br /><br /> I run 2 depth finders, and 3 bilge / livewell pumps, off starting battery. As well as lights, guages, horn, etc.<br /><br /> <br /> It seems when I plug up onboard charger, after a days fishing.<br /> <br /><br /> My starting batts. allways need a little charge. <br /><br /> A good idea ,but not ,IMHO, a necessity.<br /><br /> Water press. , temp., tach. These are a necessity, again IMHO.<br /><br /> Good-Luck,<br /> <br /> KYhunter