1964 VXL-10S; no spark

[Smiles79]

Hey all,

I have a 1964 Johnson (VXL-10S, 60 HP) and I seem to have lost spark. I had my buddy work on it and I took it out for a spin and everything was working great. Then outta nowhere it died (almost as if the ignition switch was shut off) and I haven't had spark since. The plugs, plug wires, points, and condenser have been replaced. I ruled out the ignition switch and the kill circuit. My next idea was the coil. How can I test it? Any other ideas for what to check?

Thanks

 

[F_R]

It could be the coil, They had a nasty habit of arcing out the side to the case. But more likely is the distributor rotor. They had a nasty habit of arcing through to the shaft.

You need to remove the distributor cap and see if you have spark off the coil button. If you do, everything is working up to that point and trouble is in the distributor portion (did I mention rotor?)

 

[Smiles79]

Is the coil button surface that the spring in the distributor cap contacts? How can I test to see if I have spark there?

The rotor is new, so it should be fine.

Thanks!

 

[Chris1956]

Gee, put your finger on the brass button of the coil, and give the distributor pulley a spin. A fast spin will give a good wallup.

 

[F_R]

Gee, put your finger on the brass button of the coil, and give the distributor pulley a spin. A fast spin will give a good wallup.

I had to laugh at that. Yep, it is so true, doing that will knock you right out of your undershorts..if that is what you want. Personally, I HATE being shocked, therefor the laugh. Since I hate being shocked, I lay a screwdriver across the coil with the shank touching the case and the tip about 1/4" away from the coil's spark contact. It should jump that gap with ease. (Yes, the contact for the dist cap)

 

[Smiles79]

Ok, give that a shot! Thanks!

 

[Smiles79]

Ok I did this test and got nothing. If I understand how the distributer works, it does not need to be bolted onto the motor. Is this correct? I had it off the motor and had another guy spin the pulley while I touched a screwdriver to the coil button about 1/4" away from the distributer housing and didn't get any spark.

Thanks

 

[boobie]

My guess is a bad coil or some wires grounded in the primary circuit of the coil/dist.

 

[Smiles79]

That's what I've been thinking, but I want to know for sure before I buy a new coil. How can I test this further?

 

[Smiles79]

Also, it shouldn't matter that I touched the coil button with the screwdriver tip and had a gap between the shank and the distributor housing instead of the other way around, right?

 

[F_R]

Right. As for the coil test, how does it look? Any cracks, leaking, etc? You can test the windings with an Ohmmeter, but for anything any more meaningful you need a coil tester. About an Ohm on primary winding, a few k-ohms on secondary winding. Primary is between the wire that goes to points and ground. Secondary is between the spark button and ground.

Do you hear any snapping inside the case when you spin it? That would indicate a coil that is arcing out to ground (it happens sometimes)

 

[Smiles79]

The coil looks ok to me aesthetically. I put an ohm meter across to the two leads coming from to coil (which should be the primary winding, right?) And got about an ohm. I'll test the secondary winding tonight.

I don't remember hearing any sounds coming from the case when I was spinning it but I'll listen again.

So I am correct in the assunption that the distributer does not need to be mounted on the motor for this test?

Thanks a ton

 

[F_R]

That is correct. Now put your test leads across the wire leading to the points and ground. Rotate pulley slowly and watch reading. Using lowest available range on your meter, should go to zero Ohms and infinity 4 times per revolution. Not just a few Ohms, but zero Ohms. Also make sure the wire terminals are shiny bright clean, including the screw that goes through the housing. Make sure the screw is not grounded to housing.

EDIT: Points lead disconnected from screw/coil lead for this test

 

[Smiles79]

Ok so coil button to ground shows 5.95 kohms. Points lead to ground (with points lead disconnected) was continuously infinity as I rotated the pulley. When I hooked the points lead back up and did this test, I was getting readings kind of all over the place. What does this tell us?

 

[F_R]

The readings all over the place means the magnets are generating a voltage in the coil primary----as it should. Not a valid test. What I want you to do is disconnect the points lead from the screw that goes through the housing, but leave the other end connected to the points and connect your meter leads to it and ground. Now rotate the pulley slowly and you should see zero and infinity four times per revolution. If that is what you did, and you are telling me it stays at infinity, that means the wire is not connected to the points (broken?) OR the points are not making contact when they are closed. I don't remember, did I suggest cleaning them? If they are truly clean and still not making contact, are they even physically closing? I suppose they could be grossly out of adjustment. Or defective. Whatever, they MUST be making and breaking contact, and at the right times (adjustment.)

 

[Smiles79]

I did the test as you described and I only got readings of infinity. The points are new and gapped to 0.020". I checked the wires going from the housing to the points and from one set of points to the other, and they checked out. The points sure look to be making contact... I'll check all of these things over again when I get time.

 

[Smiles79]

I did the test as you described and only saw infinity. The points are new and gapped to 0.020". The wire going from the case to one set of points and between the two sets of points check out. The points seem to be making contact when they close.

Ok so I posted this one because the first didn't seem to post until now.

 

[F_R]

If it is not going to zero, they are not making electrical contact. It is as simple as that. I would completely remove them from the plate and individually polish each contact shiny bright with some 400 grit sandpaper (the black stuff)

 

[Smiles79]

I plan on doing this sometime tonight.

I want to make sure I correctly understand how this distributor works. The positive lead from the primary winding of the coil goes to the points (which should be connected in parallel), and the other side of the points are connected to ground. When the points close, this completes a circuit for the primary winding of the coil, allowing a current to be generated by the magnet. When the circuit is completed, a higher-voltage current is induced n the secondary winding which is connected (via the coil button and the graphite brush on the other side) to the rotor, which spins and makes contact with each of the four plug wires. Is this correct?

 

[F_R]

Well almost. When the points are closed, the primary circuit is complete and the magnets passing by create a voltage & current through the circuit. The at just the right moment, the points open which causes a collapse of the flow through the primary. The collapse causes a high voltage to be induced in the secondary, which is directed to the proper spark plug as you described. This is the simplified version. There actually is a lot more going on at the same time. Such as the discharge of the condenser and reversal of the magnets polarity, etc.