Re: Help! Mercury 850 Not Firing. White Wire To Pack Not Hot?
The red wire on the Starboard side of the power pack is always energized from battery voltage.
The white wire on the same side of the power pack is energized via switched +12V, with the ign to "On" or "Start". If you're not getting voltage to the white wire with the keyswitch on, there's a problem with either the keyswitch or the wiring harness.
If you are getting power to the white wire you've got other issues. Most likely is the distributor trigger, if it's bad you have to dismantle the entire dist to replace the trigger housing; the trigger itself is encapsulated within the housing and is non-removable & non-repairable.
One word of caution, NEVER introduce power to the terminals on the Port side of the motor, where the distributor wiring connects. This will most likely blow out the trigger and/or damage the switch box.
If you haven't already seen it, there's an ignition testing procedure for the Merc CDI ign, maybe it'll help narrow down the problem:
"MERCURY BATTERY-POWERED CDI TEST FOR DISTRIBUTOR MODELS
This test is for the 332-2986 switchbox used from 1967-1978 on all the inlines.
This test assumes your coil is good (problems with CDI coils are rare).
DISCONNECT BATTERY
1. Turn off ignition;
2. Disconnect all 3 distributor wires on the Port side of the switchbox (and the ?mercury switch? if present);
3. Remove the HV lead from the ign coil to the center of the dist. cap (remember it unplugs from the coil and unscrews from the cap);
4. Reconnect the HV lead to the COIL only;
5. Position the free end of the HV lead approx. 3/8" from ground (block, shrouds etc), and find a way to hold it there;
6. Jumper the brown and white terminals on the dist. side of the switchbox to each other.
RECONNECT BATTERY
7. Check that you have +12V at the red terminal (even with the ign off);
8. Turn on ignition and verify +12V at the white terminal (same side as the red terminal);
9. Ground the black terminal on the distributor side of the switchbox - this should cause a spark each time you touch ground.
If you get spark with the distributor bypassed, and it won't fire with the distributor connected, the trigger is bad and the entire distributor housing assy must be replaced.
If you get no spark using the test, the switchbox is probably bad. In that case, be sure to check for correct power on the switchbox, check all connections, and check the coil's resistance to make sure it's OK."
HTH & keep us posted..........ed
