Need help with tachometer hook up.

[flech01]

Hello <br /><br /> I am trying to hook up this tach to my 1976 115hp johnson outboard. The tach has a sticker that says it works for 5/6 pul/rev alternator equiped outboard. The sticker also has a number on it 174887. <br /><br />I need instructions on how to hook this up.

[/IMG]<br /><br />Thanks for all the help.

 

[Joe Reeves]

Re: Need help with tachometer hook up.

Set the dial to number 6. I can't make out the other terminals, however.....<br /><br />That top terminal near the black plug looks like it would be the terminal to connect 12 volts to BUT only when the light switch is on (power to the light bulb).<br /><br />You should have a gray wire leading out of the engine to instrument wiring harness. That would connect to a terminal names pulse or possibly PUL.<br /><br />A terminal named GND, possibly some other abbreviation for ground, would simply have a black wire connected to it where the other end of that black wire would connect to a ground associated with the engine/battery (-).<br /><br />A 12 volt source that is active only when the key is in the ON position would connect to the tach 12v terminal (+).<br /><br />Gotta get these glasses changed.

 

[flech01]

Re: Need help with tachometer hook up.

I installed this motor myself all I have hooked up to it is the control box, connected with the big red connecter. <br /><br />Is it in that connector?

 

[Joe Reeves]

Re: Need help with tachometer hook up.

If that c/box has a 3 socket connector, yes. That connector would contain the 12v (+) socket, the ground socket, and the Gray wire lead socket.<br /><br />Finding the battery (+) and Ground (-) socket should be fairly easy. The remaining socket would be the gray sensor (pulse) socket.

 

[flech01]

Re: Need help with tachometer hook up.

Ok look fairly simple thanks Joe.

 

[flech01]

Re: Need help with tachometer hook up.

Will the tach still work if the rectifier is bad.<br />or if the fuse is blown.

 

[Tom Scully]

Re: Need help with tachometer hook up.

The tach will not work if the rectifier is bad.

 

[Joe Reeves]

Re: Need help with tachometer hook up.

(Small Rectifier Test)<br />(J. Reeves)<br /><br />Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction. <br /><br />Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other. <br /><br />Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires. <br /><br />Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.<br /><br /><br /> http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc

 

[flech01]

Re: Need help with tachometer hook up.

What should my top rpms be for this engine and what should it idle at.

 

[ezeke]

Re: Need help with tachometer hook up.

The Service Manual states "Full Throttle Operating Range...4500 to 5500 rpm." <br /><br />It then adds: "Note....In order to get the best performance from your outboard the upper end of this range, from 5000 - 5500 R.P.M., is the engine speed to use in selecting the proper propeller. The R.P.M. should be measured with your expected average load in the boat."<br /><br /> Service Manual Part #506919, Page 2-2 <br /><br />I don't have a reference line for idle. My 115 1976 Johnson is set to idle in gear at 650 rpm, but it runs a little rough until it warms up while out of gear. I suppose it could be set higher but I don't want to hurt the gears. This is the orignal motor on my 1976 18' Starcraft and it will still take it to 40 in a hurry. I use an OMC 14 X 17 Aluminum prop if that helps, but the boat is aluminum alloy so it is about 1/3 lighter than a comparable fiberglass boat.