1968 Johnson 65hp v4 - No Spark

[GLPmike]

No spark on all four cylinders using a spark tester.

New battery, new starter solenoid, rebuilt starter, and new plugs.

Next step?

Thanks,
Mike

 

[F_R]

Re: 1968 Johnson 65hp v4 - No Spark

No spark on all four cylinders using a spark tester.

New battery, new starter solenoid, rebuilt starter, and new plugs.

Next step?

Thanks,
Mike

Well, I could tell you to get a service manual, but it won't help you much because it will tell you to get a special neon tester which is no longer made.

How handy are you at troubleshooting electrical circuits? I can't give you the exact details, but the basics are:

1. See if you have 12V on the red wire going to the amplifier when the ign key is on. If not, find out why. If you do have 12V, go to 2:

2: Disconnect coil wire from amplifier, then unbolt coil and unscrew the whole thing from the distributor cap. Remount coil and connect amplifier wire. Rig up a spark gap off the end of the wire that you took out of the distributor cap. Crank engine: if you have spark off the coil wire the amplifier, breaker points, and coil are OK. No spark, go to 3:

3. Disconnect the wire going from the amplifier to distributor. Turn on key and brush the wire from the amplifier lightly across a bare metal item on the block. Does that create sparks off the coil wire? If yes, the amplifier and coil are good and you have a problem with the breaker points. (They are in the distributor).

4. If you have found that you have spark off the coil in #3, you have a problem with the distributor cap or rotor.

Distributor cap, rotor and breaker points are under the flywheel. You need a puller to get it off and a torque wrench to tighten the nut to 100 ft/lbs when reinstalling. All that stuff has to be clean, clean, clean. Breaker points gap is .009 at widest opening. There is an anti-reverse spring in there, a loop of silver wire. It must be in good condition and lubricated where it rides on the crankshaft with a VERY thin bead of EP grease.

We all had to go to school to learn this stuff. You just got the 5 minute course.

One last thing---a goof up in procedure can blow the expensive $$$$$ amplifier in a nano-second.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Thanks for your detailed step by step reply.

I did purchase a Johnson service manual for this motor. It was helpful in rebuilding the starter.

I did manage to complete step 1. I do have 12v going to the amplifier with the key in the ON position.

I will move to the next steps tomorrow evening.

FYI - I build PC's for a hobby and I do most of my electrical work around the house.

Thanks again,
Mike

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

One other thing. The previous owner did tell me that a new amplifier was installed recently.

Thanks.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - Still No Spark

Re: 1968 Johnson 65hp v4 - Still No Spark

Not getting any spark from coil wire (distributer end) with spark tester when attempting to turn motor over.

Not getting any sparks from amplifier wire (distributer end) to engine ground when key is in ON position.

FYI - Amplifier is making a faint ticking sound when key is in ON position. Hope it's not a bomb! Lol....

Thanks,
Mike

 

[F_R]

Re: 1968 Johnson 65hp v4 - Still No Spark

Re: 1968 Johnson 65hp v4 - Still No Spark

Not getting any spark from coil wire (distributer end) with spark tester when attempting to turn motor over.

Not getting any sparks from amplifier wire (distributer end) to engine ground when key is in ON position.

FYI - Amplifier is making a faint ticking sound when key is in ON position. Hope it's not a bomb! Lol....

Thanks,
Mike

OK, let's see if I got this straight:

You have 12V at the amplifier input While Cranking The Motor With Key--right?

You don't have sparks off distributor end of COIL WIRE while momentarilly grounding the distributor end of the thin amplifier wire, right? ( I think I suggested lightly brushing it against a bare metal grounded surface) . The wire is the lead going to the breaker points. You are replicating the action of the points opening and closing as you ground/unground it.

If both of those are true statements, amplifier or coil is shot. You need the neon tester or a DVA meter to tell which it is. A DVA meter is a peak reading voltmeter. An ordinary multimeter/voltmeter won't get it.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Sorry. I had the key in the ON position only when I tested the thin lead off the amplifier. No spark.

I will try this test again while cranking the engine later today when I get home from work.

FYI - I discovered that this motor does not have the original coil type installed. It's been retrofitted. So, I checked locally and found an OEM coil for $35. I should have it on Saturday.

On another note. This motor did not have a safety switch installed. It was removed and the lead from the starter solenoid went to ground. I just received a replacement OEM switch in the mail. Does this have any impact on my ignition problem?

Thanks,
Mike

 

[F_R]

Re: 1968 Johnson 65hp v4 - No Spark

Sorry. I had the key in the ON position only when I tested the thin lead off the amplifier. No spark.

I will try this test again while cranking the engine later today when I get home from work.

FYI - I discovered that this motor does not have the original coil type installed. It's been retrofitted. So, I checked locally and found an OEM coil for $35. I should have it on Saturday.

On another note. This motor did not have a safety switch installed. It was removed and the lead from the starter solenoid went to ground. I just received a replacement OEM switch in the mail. Does this have any impact on my ignition problem?

Thanks,
Mike

No, only limits when you can run the starter.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Not much luck this morning.

Tried cranking the motor while brushing the blue lead out of the amplifier to ground. Had a spark tester on the distributer end of the coil wire. No spark visible.

Question: Is it possible that I have a grounding problem with the amplifier. Should there be a grind wire or is grounding addressed by mounting screws only?

Thanks,
Mike

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Looks like I may have tested this with the wrong wire. Which amplifier wire goes to the distributer? I would assume it is bundled with the larger of the two plugs coming out of the amplifier.

Thanks,
Mike

 

[F_R]

Re: 1968 Johnson 65hp v4 - No Spark

Looks like I may have tested this with the wrong wire. Which amplifier wire goes to the distributer? I would assume it is bundled with the larger of the two plugs coming out of the amplifier.

Thanks,
Mike

Diagram shows a plug with 3 wires, Red is the 12V supply, Grey is the (CD) tachometer wire, Black goes to the distributor (actually timer base/points) That is the one you want. Sorry, I don't have any more information on available disconnects.

A second plug is just one wire, blue to coil.

 

[F_R]

Re: 1968 Johnson 65hp v4 - No Spark

Diagram shows a plug with 3 wires, Red is the 12V supply, Grey is the (CD) tachometer wire, Black goes to the distributor (actually timer base/points) That is the one you want. Sorry, I don't have any more information on available disconnects.

A second plug is just one wire, blue to coil.

You said you have a manual, so I assumed you know this, but perhaps an explanation of how the system works will help: With the key turned on (or cranking), 12 volts from the battery is applied to the amplifier by way of the red wire. The amplifier converts ("amplifies") that 12 volts to 300 volts and stores it in a capacitor. The black wire goes to two sets of breaker points which act as a switch, alternately electrically grounding and ungrounding the black wire. Each time the wire is ungrounded it signals an electronic switching device within the amplifier to discharge that 300 volt capacitor to the coil, via the blue wire.

The coil is a transformer. The 300 volt pulse through the primary winding induces a several thousand volts pulse at the secondary winding (that is the spark wire going to the distributor).

What I am trying to get you to do is ground/unground the black wire, eliminating the points to isolate the problem.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Thanks for the detailed explanination. Will give this another try in the morning.

Mike

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Making some progress.

I replaced the aftermarket coil with an OEM coil.

Ran the test with the spark tester on the coil wire (distributer end) and took the black/white wire lead from the amp to the distributer and brushed it to a good ground. While the key was in the ON position there was a healthy blue spark.

So, I would assume that I am good up to the distributer?

FYI-I did not run this test with the old coil. I may just to see if it's worth to keep as a backup if needed.

I then tried to get a spark off the plug wires - nothing!

Looks like I will be moving on to removing the flywheel. Which I would have had to do anyway to install the safety switch.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Making some progress.

I replaced the aftermarket coil with an OEM coil.

Ran the test with the spark tester on the coil wire (distributer end) and took the black/white wire lead from the amp to the distributer and brushed it to a good ground. While the key was in the ON position there was a healthy blue spark.

So, I would assume that I am good up to the distributer?

FYI-I did not run this test with the old coil. I may just to see if it's worth to keep as a backup if needed.

I then tried to get a spark off the plug wires - nothing!

Looks like I will be moving on to removing the flywheel. Which I would have had to do anyway to install the safety switch.

 

[F_R]

Re: 1968 Johnson 65hp v4 - No Spark

Making some progress.

I replaced the aftermarket coil with an OEM coil.

Ran the test with the spark tester on the coil wire (distributer end) and took the black/white wire lead from the amp to the distributer and brushed it to a good ground. While the key was in the ON position there was a healthy blue spark.

So, I would assume that I am good up to the distributer?

FYI-I did not run this test with the old coil. I may just to see if it's worth to keep as a backup if needed.

I then tried to get a spark off the plug wires - nothing!

Looks like I will be moving on to removing the flywheel. Which I would have had to do anyway to install the safety switch.

See, now you know the "black box" is good. Consider how many people run out and buy a new one because "It's gotta be the black box". Or, put another way, it's gotta be the part you don't understand.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Yes. Thanks for your help.

That was my original approach with the coil. But, since I was able to replace it with an OEM for $38 I don't feel as bad as dropping $2-3 hundred on an amplifier.

Any tips on going forward with the flywheel removal? Also, do you think I will be able to handle the remainder of the job?

Also, should I think about replacing the spark plug wires as well.

Thanks again,
Mike

 

[F_R]

Re: 1968 Johnson 65hp v4 - No Spark

Yes. Thanks for your help.

That was my original approach with the coil. But, since I was able to replace it with an OEM for $38 I don't feel as bad as dropping $2-3 hundred on an amplifier.

Any tips on going forward with the flywheel removal? Also, do you think I will be able to handle the remainder of the job?

Also, should I think about replacing the spark plug wires as well.

Thanks again,
Mike

The service manual will pretty well explain the flywheel removal and reinstallation. Make sure you have the tapers clean and dry and use a torque wrench to tighten the nut to specs. The anti-reverse ring might be half the problem in there. If run dry they disintegrate and fling powdered metal all over everything. Of course powdered metal is a spark conductor. Clean everything , make sure the points are gapped correctly, lube the anti-reverse ring with just a very thin bead of EP grease. Test the plug wires with an ohmmeter. Put grease in the dist towers as the manual says to prevent arc-out. Truth is the distributor cap and rotor are the sorriest part of the whole motor. I was very glad when they did away with it.

 

[GLPmike]

Re: 1968 Johnson 65hp v4 - No Spark

Thanks.

I will let the penetrating oil soak overnight on the flywheel nut. Will give it a try tomorrow.

 

[F_R]

Re: 1968 Johnson 65hp v4 - No Spark

You don't need penetrating oil, you just need to get meaner. It will come off if you show it who's boss.