no spark

brodie123

Petty Officer 1st Class
Joined
May 4, 2008
Messages
279
I bought a seized motor just for the fun of learning to rebuild it. (Johnson 40)

I have it all back together but no spark. The coils are in rough shape and I have no psark so I'll replace them but want to make sure I'm reading my manual right for wiring.

Other than the plug wires, there are 2 wires off the armature plate - my understanding is the one with the scissor knife connect goes direct to +12v. The other goes to +12v as well. As long as I have these 2 wires on +12V then I should get spark "if" everything is working right.

Please let me know if I have this right.

Thx
 

brodie123

Petty Officer 1st Class
Joined
May 4, 2008
Messages
279
Re: no spark

still reading my manual here - starting to look like the 2 wires are actually cut-off. Where to run the motor they stay un-connected and to shut down the motor they go to ground killing the spark.

Is this correct or the prior?
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: no spark

What year/model is the Johnson? If you hook it up wrong and apply 12v to the coil(s) you will blow them.

Do you have a manual? It will help.
 

brodie123

Petty Officer 1st Class
Joined
May 4, 2008
Messages
279
Re: no spark

It's a 1962 40 HP Johnson - I think they are ground leads. My understanding is that the motor runs when they are disconnected and stops when they are to ground. Sound right?
 

samo_ott

Vice Admiral
Joined
Jun 18, 2006
Messages
5,125
Re: no spark

Yes, those 2 wires are the kill wires. If they short together the engine will stop/die. They should both go to the ignition switch.
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: no spark

What you are describing is the kill circuit for a standard magneto ignition system. Two wires go through the armature plate and connect to the point sets, one to each set of points. The other end of these two wires goes to a normally open set of dry contacts (either keyswitch or push button). When these two wires are NOT connected, the magneto ignition will work, motor should run. If these two wires are shorted together, it should kill the spark to the plugs and kill the motor. DO NOT connect either of these two wires directly to 12VDC....

Why is it when folks post questions , they don't follow the mods suggestions as outlined here:
http://forums.iboats.com/showthread.php?t=250879

Note #9 in the list.

Posting questions without the model number can only produce guesses and wrong assumptions.
 

brodie123

Petty Officer 1st Class
Joined
May 4, 2008
Messages
279
Re: no spark

Thanks - that's why I post here when I'm unsure.

So short together and not to ground? I would have thought putting them to ground. Please confirm that they short together and not to ground.

Also, the coating on the coils when I took it apart is cracked and chipping off. Good indication they are dead?

Any ideas on the cost of replacing them?
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: no spark

Short pair to kill motor.
Cracked coils are bad replace them.
Approx 20-25.00 each
 
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