OLD coil for 1964 Johnson 90hp ($90!!!?)

[jiminmontana]

I see that the ignition coil for a 1964 Johnson Meteor 90 hp has not been made in a long time. Freshest new one I can find was made 20 yrs ago. Do they go bad sitting on the shelf with the oil weakening the plastic, etc.? Plus, why pay $90 for an OLD coil when a new one may work for $20?

The coil is shaped like a small bottle, OMC part #379569. High tension comes out the "mouth" of the bottle and the 2 electrodes are on the flat "base". In the middle on the side is a 3/8 long tip to hold the coil in the mount.

Is there a part being made today that will fit this motor, even if a bracket needs to be fabricated?

Part available is at this link;:
http://www.boats.net/parts/search/B...16C 1968/HEAD AND ROCKER ARM GROUP/parts.html

 

[Chris1956]

Re: OLD coil for 1964 Johnson 90hp ($90!!!?)

I wouldn't think they would go bad from sitting. Look for cracks in the plastic.

It sounds like you have a battery-coil ignition on that motor. As an experiment, you might hook up an old ford coil and ford condenser. You need to match them, for best results. A universal coil and condenser may also work.

I once converted my old Johnny fat-fifty (magneto ign) to a battery-coil ignition using a ford coil and condenser, and some creative wiring.

 

[F_R]

Re: OLD coil for 1964 Johnson 90hp ($90!!!?)

1964 had a one-ohm resistance wire built into the wiring harness (cable to the front of the boat). So, do you have the right cable? Could be why your coil is bad, I dunno. Anyhow, it will work just fine on a car coil if you get the voltage right.

 

[jiminmontana]

Re: OLD coil for 1964 Johnson 90hp ($90!!!?)

Yes, sir. The motor's service manual mentions a resistance wire, but does not give the ohms. Just 1 ohm? Anyway, the wiring has been spliced and messed with quite a bit so I had no confidence that measuring the ohms that I have NOW was correct for the next coil and wiring harness that I'll fabricate. The wiring looks just as rough as the paint job on my blog.

The breaker points show usage, but are not burned up (blue), so it would SEEM that the coil was not overly hot. I think that coils today often come with their own resistors (?) and that these automatically switch off when you go past idle to give the hotter spark. If I were to skip the resistor wire, I would put a resistor in-line -- I would click an automatically toggling OFF switch to route around the resistor while starting the motor to give a little more spark if needed - just for firing initially -- then release the toggle to circuit back thru the resistor once running. Are you sure it's just 1 ohm? I have been looking all over and can't find that number.

Finally, you mentioned the voltage. Did a '64 run on 6V from the coil/junction box or 12V? I noticed in the parts list that a voltage regulator is in the junc box, but I don't know what it does - to minimize spikes or to cut in half. (part # 379476)

Finally (really), I think that there is a difference between coils on modern fuel injected and computerized cars versus the old coils from the distributor days -- yes?

Thanks for sharing your knowledge!

 

[1946Zephyr]

Re: OLD coil for 1964 Johnson 90hp ($90!!!?)

If you found a voltage regulator, it means that you have a charging system on that motor all wired in.

I do believe that system is 12 volt, but you can easily tell for sure, by looking at your battery. I think all OMC's were 12 volt by 57 or 58.

 

[F_R]

Re: OLD coil for 1964 Johnson 90hp ($90!!!?)

Yes, sir. The motor's service manual mentions a resistance wire, but does not give the ohms. Just 1 ohm? Anyway, the wiring has been spliced and messed with quite a bit so I had no confidence that measuring the ohms that I have NOW was correct for the next coil and wiring harness that I'll fabricate. The wiring looks just as rough as the paint job on my blog.

The breaker points show usage, but are not burned up (blue), so it would SEEM that the coil was not overly hot. I think that coils today often come with their own resistors (?) and that these automatically switch off when you go past idle to give the hotter spark. If I were to skip the resistor wire, I would put a resistor in-line -- I would click an automatically toggling OFF switch to route around the resistor while starting the motor to give a little more spark if needed - just for firing initially -- then release the toggle to circuit back thru the resistor once running. Are you sure it's just 1 ohm? I have been looking all over and can't find that number.

Finally, you mentioned the voltage. Did a '64 run on 6V from the coil/junction box or 12V? I noticed in the parts list that a voltage regulator is in the junc box, but I don't know what it does - to minimize spikes or to cut in half. (part # 379476)

Finally (really), I think that there is a difference between coils on modern fuel injected and computerized cars versus the old coils from the distributor days -- yes?

Thanks for sharing your knowledge!

The '64 ran on 12 volts, reduced by the resistor. Of course the other half of the equation is the resistance of the coil's primary winding. The actual measured voltage at the coil terminal---I don't know. Yes, 12 volt car coils have a built-in resistor, at least as far as I know. But I'm an outboard mechanic, not a car mechanic.

The voltage regulator in the box is for charging the battery, part of the alternator system.

I am 100% sure it is a one ohm reistance. I can prove it if you insist.

The modern electronic ignition coils are a completely different critter than the old battery/coil/points system. The run on much higher voltage pulses applied to the primary winding. Not even on the same planet by comparison.

 

[Chris1956]

Re: OLD coil for 1964 Johnson 90hp ($90!!!?)

Jim, The old Ford Ign systems ran on about 8VDC using a inline, descrete resistor to drop the voltage. They wired the coil + side to the starter solenoid primary + connection, to pump +12VDC into the coil while cranking. Pretty slick eh?

The Auto coils sometimes had built in condensers to help supress radio inteference. These were different than the ones connected to the points.

 

[emckelvy]

Re: OLD coil for 1964 Johnson 90hp ($90!!!?)

Any automotive coil that is for use with an external ballast resistor should work, providing the original ballast wire is still doing its job.

You could also cut/remove the built-in ballast wire and either use the above with external resistor, or just get a coil with internal resistance.

Years and years ago I horse-traded an old beat-up 90hp V4 to a good friend of mine and he put it on an old 14' Bayliner runabout.

He was having a lot of trouble with the ign, fouling plugs and such.

He installed a Mallory Supercoil which had a ton of spark energy. The motor ran like a Million Bucks after that. Pretty sure he took out the old ballast wire, too.

At any rate, even a Plain-Jane El-Cheapo auto coil will be better what you've got. An inexpensive MSD coil from Jegs or Summitracing will give you good spark and should improve idling and overall performance.

The other thing my buddy did that drastically changed the reliability of the Ol' 90 was to install an inline fuel filter off the tank. The 4-bbl carb is pretty sensitive to fuel contamination and the filter cured that problem.

With all the ethanol in the gas nowadays, a water-separator filter would do a great job of keeping water/junk out of the carb.

HTH........ed