spark loss after starting????

[flamejumper45]

I have a good one here...I have a '73 850 mercury...I have spark in during starting, but loose it in run. check for power on red and white wires on switchbox and have just better than 12volts. while engaging starter engine fires and busts, but when key is released to run position nothing. I have replaced key switch and harness from control box to engine. harness on engine in good shape. checked all wires against wire diagram. switchbox has been swapped out with good box off a '75 850 still no fire in run position. coil tested and is firing while engine spins. can not find any shorts in electrical system anywhere. thanks in advance for any help.

 

[studlymandingo]

Re: spark loss after starting????

HMMM... Sounds like something in the ignition switch still. Like instead of providing current to the ignition while in the "run" position it is switching off.

 

[Chris1956]

Re: spark loss after starting????

Flame, Hook up a jumper wire from the red terminal to the white terminal on the switchbox. If the problem persisits, it is not your ignition switch, since you just hotwired the motor. Here is the troubleshooting guide for the distributor models, again thanks to Clams.

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 (most all are).

DISCONNCT BATTERY

1. Turn off ignion
2. Disconnect all 3 wires on the distributor side of the switchbox.
3. Remove the HV lead from the coil to the center cap (remember it unscrews
from cap)
4. Reconnect that HV center lead to the COIL side only.
5. Position that HV lead about about 3/8" from ground (block, shrouds etc)
and find a way to hold it there.
6. Jumber the brown and white terminals on the dist. side of the switchbox
together.

RECONNECT BATTERRY

7. Check that you have +12 V at red terminal.
8. Turn on ignition and verify +12V at white terminal (on red terminal side)
9. Touch the black terminal to ground - unit should cause spark each time
you touch ground.

If that passes and it won't fire at all, suspect the trigger

 

[studlymandingo]

Re: spark loss after starting????

Give us an update.