i have a 1976 mercury 115 hp motor,will not start

[zeus7888]

i have replaced the head with a rebuilt one,replaced the switch box,new,new starter switch,recterfier is working fine,coil shows good,dist. cap has new rotor installed ,including a new carbon brush,and i still am not getting any spark to the plugs,i have taken the wire from the coil to the dist. off and shorted it to ground while trying to start it,and get no spark from that,even took the green wire going to the coil off and grounded that,no spark coming from the green wire,something is telling me that this new switch box is faulty.Can u tell me how to test this switch box?please,

dist. side had
black tab-top
white tab-middle
brown tab-bottom

other side has
white-bottom
red-second
brown-third-i have never hooked anything to the brown,
green- top
How can i test this to see if it is good or not?
Thank you for your time in reading this,frusted trying to be a fisherman.

 

[Moody Blue]

Re: i have a 1976 mercury 115 hp motor,will not start

Here is a link to the wiring diagram for your motor to verify the proper connections.

http://www.maxrules.com/oldmercs/Wiring/1966ona/50.jpg

A couple things to check first off.

1) Disconnect the mercury tilt switch connected to the distributor side of the switchbox.
2) Verify that you have +12V at the white wire/terminal on the non-distributor side of the switchbox when trying to start. Red wire/terminal on the same side should always have +12V on it.

The brown terminal on the switchbox was used as a tach connection but is no longer used with the newer type tachs.

There is a thread somewhere on these forums on testing the switchbox but I can't put my finger on it right now. Here are a couple other good resources though.

http://outboardparts.com/mercury/miscellaneous/troubleshootinghelp.htm

http://www.boatpartstore.com/page18.asp

http://www.maxrules.com/cdi/TroubleshootingGuide.pdf

http://dolphinmarineservice.homestead.com/tech.html

 

[mke039]

Re: i have a 1976 mercury 115 hp motor,will not start

I agree, when you turn your key to the first click, this should energize the bottom white wire (on starboard side of engine) with 12v. Check this first! You will not get a spark if the white wire does not get voltage.

Let us know what happens.

Sometimes the wires in the switch get corroded and break, they are crammed into the control, shift box and over the years it can get messy.

 

[zeus7888]

Re: i have a 1976 mercury 115 hp motor,will not start

thank all you good people for responding,such good people as you is what makes this world go around,again thank you,now ,you not going to believe this,and i am such a dummy not to check this out from the start,but my harness coming from my switch going to the motor plug had a few breaks in it so i peeled back the insulation that covers the wires,and found a few that were in very bad shape,so i soldered the together,or so i thought,well,come to find out all but the white wire held,so i was not getting anything to the switch box from the white wire.So simple,yet so hard,lol, gose to show me anyways,look for the simple things first,and work your way up.OOOO,by the way,the dang thing runs ,lol

Thanks again for all your help and response.