tach hookup on merc 1150

[phatmanmike]

hello. 1976 merc 1150.<br /><br />teleflex tach #58477 , for use with 12 pole outboards. teleflex say this is for "other " mercs, not the little japanese ones, but all " others"<br /><br />so, it has 3 terminals on the back......<br />I ignition<br />S sender(stator or rectifier)<br />G ground<br /><br />i hooked up as said and it went to zero and stayed there with motor running. no movement. i just looked at the teleflex website and it shows that the "S" should go to BOTH yellow stator wires, and i only did one yellow wire. could this have been my problem, and did i just answer my own question?

 

[erniex]

Re: tach hookup on merc 1150

Mike,<br /><br />On page 2 of those installation instructions it says to hook it to either one of the yellow terminals at the rectifier. I think the dotted line on the diagram just indicates you can hook it to either one.

 

[phatmanmike]

Re: tach hookup on merc 1150

UPDATE: i tried it to both wires and also to one wire, and it does nothing either way.<br /><br />i tried it at the rectifier and also directly to the stator wire...nothing

 

[Chris1956]

Re: tach hookup on merc 1150

Mike, The Tach should work in the 12 pole setting. The brown wire from the rectifier (connected to either one of the AC terminals) should be connected to the tach via the plug on the control box. The other two connections on the control box are +12V and ground. I would use a voltmeter to assure the tach is getting the +12V and ground on the proper terminals. Also, the voltmeter should read an AC voltage on the tach sending wire when the motor is running.

 

[phatmanmike]

Re: tach hookup on merc 1150

i am not using the controll box plug, as i have an aftermaket control box.<br /><br />teleflex service technicians said i should have 5-7 volts AC coming from stator around 2000 rpms, i measured this and i have about 15-17 volts.<br /><br />my rectifier is shot. i just found this tonight durring testing, would this matter, as i am connected directly to the yellow wire coming from stator?<br /><br />also, tach roms jump around slightly, like about 200 -300 roms back and forth, jumpy like , espicially around idle speeds.<br /><br />NOTE: all testing has been done on muffs at home

 

[Chris1956]

Re: tach hookup on merc 1150

Mike, If your rectifier is bad, it may be allowing AC voltage to get onto the battery charging circuit. This may affect the tach. I also think will have high AC voltage( more than 12V) on your stator, if the rectifier is bad, since the battery provides a load to the charging system and acts as a voltage regulator.<br /><br />I recommend you disconnect the Stator wires at the rectifier until you are able to replace the rectifier(get a 25 Amp Full wave (or bridge) rectifier ($4) at Radio Shack, and connect the -12 spade connector to ground). Connect 12VCD, a single Stator AC wire and ground to the tachometer and try it.