72 Merc 650 no spark please read and help!

[CluelessinGresham]

I have a 72 650 and have replaced the switchbox and coil and still no spark. Where do I go from here? I will try some of the ideas from the posts I have read but they are a bit confusing and I'm no pro mechanic so any help here would be great, thanks.

 

[Laddies]

Re: 72 Merc 650 no spark please read and help!

Do you have 12 volts on the red treminal of the switch box all the time and with the key no you should have 12v. on the white terminal, disconnect the mecury switch and ck for spark,if you don't remove the 3 wires from the dist side of the box connect a jumper wire between the white and brown terminal on the box, turn the engine to number1 cyl, TDC put a plug in the wire and ground it, turn the key on and use anouther wire and arc the black wire to ground ever time is is arced the system should fire if it does you have a bad trigger, if not you have a bad box