77 merc 115 no spark

[bigal84]

I have 77 cd battery ignition merc 115 hp which has no spark. I have gone through all the troubleshooting steps to determinewhats wrong, but i am still not sure what is wrong. I can not determine wether it is the sitchbox or trigger. First of all the spark is very intermittent it sparks maybee once if you hold the key for 10 seconds. It only has 2 volts at the brown trigger wire and the test procedures says it should have 9, but when i jump the switch box and ground it out it clicks every time like i believe it is supposed to. Whats wrong? someone please help me before i just buy everything.

 

[Chris1956]

Re: 77 merc 115 no spark

Did you run the test where you disconnect the brown, white and black wires on the dissy, jumper the port side white and brown terminals on the switchbox and test for spark when you ground the port side black terminal? If the coil is good, it should spark every time. If not, make sure the switchbox has +12VDC on the red and white terminals on the starboard side. If all this checks out, the switchbox is likely bad.

 

[bigal84]

Re: 77 merc 115 no spark

I did perform that test. I didnt check the coil for spark but when i tapped the black wire jumper on a ground the switchbox makes a loud clicking noise every time. And i definetley have 12v on both the white red terminals. I thought that is what the instructions meant when it says unit should fire each time(the clicking noise). the thing i dont understand is when the trigger wires are connected to the switchbox the brown terminal only shoots out 2v with the key on. is it the triggr or switchbox?

 

[bigal84]

Re: 77 merc 115 no spark

I changed the distributor and she sparks like a beast thanks for the help.