Electronic ignition for Mercruiser 170 (1985)?
 

My distributor shaft is pretty sloppy and a supplier out here (pacific northwest) says electronic ignition will really boost performance. Since I need to fix it anyway I thought this might be a good time to do it right.

Any comments on whether electronic ignition is worthwhile and if so recommendations on what to get? I'm figuring on gettting a high voltage coil, etc.

A motorhead friend is suggesting a local ignition shop that does all kinds of engines but the supplier seems to have a lot of experience with 170's - I'm looking for a little more input.

I really want to be ready this year - supposed to be a record Salmon run - want to be in good shape for that.

Pertronix 2 w/Flamethrower 2 coil and 8mm plug wires. I also opened plug gaps to .045. Good starts and will idle smoothly at 500 to 550 rpm.

pertronix is the way to go, but if your distributor shaft is sloppy, it may create new problems, see if you can get the slop out of the shaft before you add to the issue. Is it in the shaft to housing fit? Or is it in the upper shaft to lower? Remember you can use a distributor for a 3.0L/2.5L 120/130/140 as a parts distributor if you can't find a 3.7L. The electronic ignition will help with the slop because there's no side load from the points, but it could lead to erratic timing if the there is enough play.

Yep! The Pertronix ignition and the Flamethrower coil are definately the way to go!! Changed my 170 over years ago when I rebuilt the motor and it was a really good upgrade. Starts alot faster and runs 100% better. Keep your old points and condenser just in case.

Thanks - I love it when everybody agrees. I need to dig into my manual about the upper/lower shaft thing and poke around the distributor to get the problem narrowed down. I'll get back with more questions when I understand what I don't understand better.

The pertronix ignition module is really easy to install, Also I was told never leave your switch on when not running it could damage the module. I think Mallory makes a simular unit but havent heard anything about.

cfelton ...you are correct about leaving the switch on with the pertronix 1, but the pertronix 2 is supposedly (smarter) and will shut down to protect itself also on low and high voltage.

Don't tell that to the model t guys. A common conversion on the model T is to add on a VW distributor, and many have added in the PERTRONIX 2 and had them melt down. One guy had an actual fire from it and did quite a bit of damage.

Model T and VW cross had to be bad voodoo. Fire on V20 is no good.:sad:

We, my brother and I own an 87 V20 and we just had the ignition upgraded to an electronic unit. Do not know what brand, but we were assured a faster starting engine and slower trolling speed as we would be able to idle the engine down much lower than before. Haven't had it on the water yet, but we are expecting good things. Make the change, I'm sure you will be pleased. Have a safe boating season!

Thanks for all the great replies - I'm hoping this boating season will be a little LESS safe for the fish swiming near my V than last year:). I'll post progress and results.

Petronix
 

I installed the Petronix ignition last year and for the money, it was one of the best upgrades I did. Super fast starts and smooth running. I cannot comment on fuel economy because I did not take a baseline prior to the installation but I am sure I am doing better than points.

I picked up the rebuilt distributor with Pertronix kit in it and Flame Thrower coil today. The old shaft was gauled badly and I can only imagine how bad the bushings were worn - no more side play and I'm pawing the ground to get the new stuff installed. Hopefully this weekend - we'll see if work cuts me a little slack.

Well, no continuity in my existing wires - planning to get some bulk MSD spiral core wire and make up a set. Any comments or warnings before I order the wire? Also, on a boat the size of a V-20 is there a requirement that the wire be USCG approved? MSD sold their marine business, but says there's no difference in the insulation on the marine and the automotive product.

Are the wires completely open circuit? Spark plug wires could be up to 1200 ohms per foot . It would be unusual if they are all open circuit.

what he said, make sure you have the ohm meter in the correct range

They have that carbon??? kind of core - Looking at the coil wire, I could see the open circuit at one end. I checked the coil and one plug wire with my best, auto-ranging meter and got the same reading I get when I hold the probes 3' apart:) - I think they're open. I could probably take off the end connectors and re install them. Do you think it's worth messing with or just do the new wires - any reason not to use the spiral core?

get new wires, oem wires aren't carbon core. I sell Megamag marine wires, they are decent. for my own personal use, I get the Moroso spiral core

I got MSD bulk spiral core wire and multi-angle plug connectors. My son (mechanic) and I almost got hernias getting one of the boots over the wire and then back down over the connector. We slathered it with dielectric grease but it was still really hard to get it on and then couldn't twist the wire in the boot to align the MSD logo so it will be where I want it when I bend the connector.

Any tips would be appreciated. Thanks

Silicone spray lube and the boots will slide right on. Just keep in mind once the spray dries, the boot will be locked in place.

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

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).

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.

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.:beer:

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

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

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.