Stumpped on Magneto problem. "FIXED"! (Maybe)

[bob1340]

1971 18 HP Evinrude.

No fire to the bottom cylinder.

I have new coils, points and condensers.

Wires for the shut off switch are okay, no shorts.

Still no spark to the lower cylinder.

I removed the wires for the points, condensers, and shut off switch. With an ohm meter I checked the continuity between the end of the plug wire and the frame of the coil. Brand new coils mind you. The coil for the top cylinder shows zero ohms when I check from the spark plug wire to ground. This is the one that was firing so I suspect that reading is what I should get. The bottom cylinder shows a slight resistance once or twice than it shows zero!!! Kind of weird, I can check it 10 times and get ohms one, and zero the next.

The old coils show zero on one, and a slight resistance on the other. But they are consistent.

I have no coil checker.

I'm lost, what should I do and in what order? Thanks.

 

[bktheking]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

Post a top pic of the assembly, could be a wiring issue.

 

[tashasdaddy]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

are you absolutely sure you got the plug wire centered and all the way into the new coil. 99% that is the cause. i also strip back 3/4 inch of insulation on the plug end and wrap it around spring to make sure good contact, before installing boot.

 

[Daviet]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

You could swap the coils and see if the spark moves wit the coil.

 

[bob1340]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

Post a top pic of the assembly, could be a wiring issue.

No wiring issue, I am sure of that. Please read my post in regard to the ohm readings.

are you absolutely sure you got the plug wire centered and all the way into the new coil. 99% that is the cause. i also strip back 3/4 inch of insulation on the plug end and wrap it around spring to make sure good contact, before installing boot.

Plug wires are good, good contact. What is the spring you are talking about. I can't remove my boots on the plug end. But I have no issues with the plug wires or connections. That was not my question. Please read my post in regard to the ohm readings. Why is this brand new coil reading a slight internal short on the HV side? Why do the 2 coils read different?

You could swap the coils and see if the spark moves wit the coil.

Correct, if I swap coils I get fire in the other cylinder.

My question is, why is the brand new coil burnt out if it is? They ain't cheap so I don't want to do this again.

The old coils read the same as the new ones on an ohm meter.

I guess at this point I'll stick the good old coil on and see what gives.

As far as I know the new coil has never fired the spark to that plug.
I find no shorts and everything is new except the flywheel and plug wires.

 

[bob1340]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

Don't think I am sounding pissy here or something. If I sound that way I apologize.

I am just trying to figure out if the coils should show slight ohms between the spark plug cable and the coil frame.

Let me show 2 examples:
1. The coil is on the bench. No wires are hooked to it except the spark plug cable. I get varied readings on one coil between the plug wire and coil frame. Sometimes we have ohms, sometimes we don't. The work bench has a plastic cover now so it ain't grounding to the bench.

The reading I get is not a full ground, the needle sweeps about 1/3 way across the dial.

2. Install the coil on the armature and it always shows a reading between the armature/ground and plug cable. Yes, the ground wire from the coil is hooked up. No, the points wire or any other wire is not connected.

Other coil, no reading at any time. The coil with no reading is the coil that works.

 

[tx1961whaler]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

I have received defective brand new coils before, so it's not unheard of.

 

[bob1340]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

I have received defective brand new coils before, so it's not unheard of.

I think that is what is happening! Geeze, these things cost over $40.00 shipped! WTH!

Next question, If I want to put new HV cable on what do I use? Will the local boat shop have cable and boots and ends? All I can fine in Autozone and such is radio suppression wire.

 

[bob1340]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

I am getting a good multi-meter tomorrow and going through all these tests:

http://assets.fluke.com/appnotes/electricalpower/B0271b_u.pdf

I hate ignition issues. What is funny, or sad, is I had a problem with the bottom cylinder not firing so I changed out all the components and now I have the same issue!! The coils even read the same!

 

[tx1961whaler]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

The coil is $16.19 here at iboats. Shipping is very reasonable also:
http://www.iboats.com/mall/partfind...gd_poid=109172&gd_row=72&**********=737647003

 

[bob1340]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

The coil is $16.19 here at iboats. Shipping is very reasonable also:
http://www.iboats.com/mall/partfind...gd_poid=109172&gd_row=72&**********=737647003

Thanks. I am going to stick the good old coil on first then see if it runs.

 

[bob1340]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

Take it apart, put it together, take it apart, put it together.

LOL


After a lot of hassle and torment the problem was a condenser.
I feel like an idiot not testing them first!!!!!:redface:

I stuck one of the old ones an and it works fine now.


Here is where I think I screwed up, please advise me if you also think this is what I screwed up. Most folks like pointing out screw ups!!

When I put the new points in I also installed a new cam oil wick as it was supplied with the points. I think I stuck it in 90 degrees off of where it should have been in the holder plate. It pulled out and a small piece tore off and stuck under the rear cylinder points cam follower which would not allow the points to close. Because of this I am guessing the condenser over loaded.

Any thoughts?

 

[F_R]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

It is impossible to "overload" the condenser. But if the points weren't closing, it obviously would not have spark on that cylinder.

Condensers are a strip of wax paper and a strip of foil, wrapped together. If electricity leaks through the wax paper, the condenser fails. Nothing really "causes" it, but age is a big factor.

Coils' resistance should be around an ohm on the primary and several k-ohms on the secondary. Actual resistance varies with manufacturer, and even year.

 

[bob1340]

Re: Stumpped on Magneto problem.

Re: Stumpped on Magneto problem.

It is impossible to "overload" the condenser. But if the points weren't closing, it obviously would not have spark on that cylinder.

Condensers are a strip of wax paper and a strip of foil, wrapped together. If electricity leaks through the wax paper, the condenser fails. Nothing really "causes" it, but age is a big factor.

Coils' resistance should be around an ohm on the primary and several k-ohms on the secondary. Actual resistance varies with manufacturer, and even year.

Thanks. The one new condenser shows a solid short.

 

[14ftgrumman]

Re: Stumpped on Magneto problem. "FIXED"! (Maybe)

Put one of the old coils back on and see what happens.

 

[bob1340]

Re: Stumpped on Magneto problem. "FIXED"! (Maybe)

Put one of the old coils back on and see what happens.

The coils were fine, it was a bad condenser.

After a lot of hassle and torment the problem was a condenser.
I feel like an idiot not testing them first!!!!!:redface:

I stuck one of the old ones an and it works fine now.