Electronic ignition for Mercruiser 170 (1985)?

[spareparts]

mercury power tune sprayed on the boots will make them jump on in place. Its so slippery, I don't bother putting the boots on before I crimp the terminals. It dries up quickly. Works real good on exhaust hose and shift cable bellows

[scook]

I finally got the Pertronix ignition installed and I have no spark.

• There is just short of 12 volts at both sides of the coil, so there's power and the primary has continuity.
• The secondary has continuity - I think it was around 12000 Ohms resistance - I can re-check that if it becomes important.
• Tried #1 spark plug laying on ground and also put a metal extension on the end of the coil wire and held near ground cranked it plenty long for something to happen - nothing.

I'm thinking it's either the ignition module or something wrong with the primary wiring (which I put back the way it was).

Any diagnostic suggestions will be appreciated (I'm a little above my pay grade as far as really understanding the system).

[Striper80]

I'm not 100% familiar with your previous ignition, but if it was a points ignition they usually have a resistor to step the voltage down. I have no idea where it would be on your engine but I know in cars points run on a lower voltage.

[twhrider2]

Scook, Sorry to hear about your troubles.. but a couple of things come to mind.
What type of coil do you have..if new then it is probably internally resisted so do away with purple resistor wire as per pertronix instructions.
My engine was starting and running great then suddenly would not fire. Checked, tested, pulled jumpers made phone calls..nothing. Turned out to be my "rebuilt" starter. Even though it was spinning and sounded good it was dragging enough to pull voltage down and the pertronix 2 was shutting down on low voltage. New starter and bingo!!!! (Thanks for the tip Spare).
These engines really put a load on starters and the pertronix will protect itself with high or low voltage shut down. Also might try pulling a jumper from battery+ to coil + and see what happens. Not a mech. by any means just some areas I have already delt with.
Good luck and I'm sure Spare and Ferm will be along shortly with more ideas.

[spareparts]

pull all the wires off the coil. hook the red wire from the pertronix to the + terminal on the coil, hook the black wire on the pertronix to the - terminal on the coil. Use a jumper wire and hook 12v to the + terminal on teh coil, spin the engine over and see if you get spark. If not, check the sensor gap and go back thru the pertronix trouble shooting guide. If you do get spark, pull your jumper wire and hook the purple/white wire up on the + terminal with the red pertronix wire, spin the motor over and see if you get spark, if you don't you've got voltage issues, cut the harness back till you get to a solid purple wire and bypass the resistor, some used the electric choke as a resistor, some used a small loop of hard wire as a resistor. If you did get spark, then hook up the grey wire on the - terminal with the black pertronix wire, spin the motor and check, if you didn't get spark, un plug the shift switch harness(white green wire) and retest

[scook]

Thanks guys - that sequence makes perfect sense. I'll dig into it as soon as I can sneak out of the office.

[scook]

By the way Ferm & Spare - thanks for the tip for getting the plug boots on the wires. I was at the Merc dealer, so picked up some Power Tune - they pretty much put themselves on with that lube. I still can't figure out why the dialectric grease didn't work hardly at all but it didn't.