Mercury 850 no spark

SAT_Homeless

Recruit
Joined
Mar 23, 2021
Messages
2
Hello everyone. I have a Mercury 850 1975 and I have been working on it for weeks and cant get any power from the terminals on the switch box that go to the coils (green to ground). I have tested the stator and its good and is sending voltage to the switch box. I tested the trigger ( it has 4 wires) and I think it might be bad since i got 800 ohms across 1 of the wires instead of 2. Is there any way to bypass it to try to get spark? Im certian that everything is wired correctly and I replaced many of the bad wired and made repairs. I cant remove the flywheel to get the trigger off.
 

Faztbullet

Supreme Mariner
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Mar 2, 2008
Messages
15,934
Did you DVA test the voltage from stator? What was it if you remember?
 

SAT_Homeless

Recruit
Joined
Mar 23, 2021
Messages
2
I apologize for not editing it but after some hard work i managed to get the flywheel off and as I suspected there was a bad trigger wire. The stator was producing about 50 volts on 1 wire and 200 is on the other. Is there any way to bypass the trigger to test for spark? The only other problem I could see is a bad switch box but I dont want to waste money on the trigger if the box is bad too.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,453
A 1975 Merc 850 would have a distributor and battery CDI ignition. A 1976 Merc 850 would have ADI ignition, as you describe. A small point.

See if there is a test for your ignition components on the CDI Electronics web site.
 
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