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Ignition system problem

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dbarnes

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"I have a 1961 johnson 75 hors

"I have a 1961 johnson 75 horse motor with magneto style igniton. It does not want to start. I went throught the test procedures as follows. First disconnect the wire from the igniton switch and check for spark. I did this, no spark. Second rig up a wire from the contact surface of the coil to tester, (in this case it is a tester I made out of nails and a board with about 5/16 inch gap between the nails.) I then checked for spark and got the blue "snappy" spark that is described in the service manual. That lead me to believe, according to the info on this site, that the rotor button is my culprit. I was just wondering whether there could be another problem, such as the contact spring inside the distributor cap, or the wiring from the points assembly to the "lug" that the ignition switch wire connects to, that I need to check before spending money on the rotor? What other test procedures can be done. I have checed the "lug" where the ignition switch wire is connected with a test light and I get a very small amount of voltage there while cranking. Is this normal? Also can anyone tell me where i can get a cap and rotor for this. Keep up the good work.Your site is more informative than the service manual is. thx
"
 
"If you have a Volt-Ohm meter

"If you have a Volt-Ohm meter (multitester).. you need to check the voltage (during cranking) from the ign switch, and continuity to ground for the points. Especially a pronounced change as they open and close.
I don't have a '61 Manual... so I'm not sure if your ignition system uses an "internal resistance" wire from the IGN terminal on the switch- to the positive side of the coil. It should be white with a red tracer(stripe). If yours does- that could be breaking down and have too high resistance to get a really good spark. You "can" bypass that wire with a 12V+ lead direct from the battery(to the + side of the coil), and check for better spark... but you must NOT leave it that way. Having full-12V current to the points- will burn them quickly. You must only use the bypass wire during cranking- and while it's running. Don't leave it hooked up when the points are closed and the engine is not running.

As for parts- contract Joe Reeves on this board. He has helped me immeasureably with my parts location for my Evinrude.
(Thanks Joe)

Ray"
 
"If the distributor cap has th

"If the distributor cap has the brush and spring assy installed (the brush that makes contact with the rotor), in all probability the cap is okay.

You have described a V4 magneto with a faulty rotor, part number 580260... NOT 580338.

Your rotor MUST have the weird working terminal end that looks something like a strange hook, NOT a straight squared off terminal end such as you would see in automotive type ignition systems.

Sorry to say I have no more of those items in my remaining stock."
 
"Joe, do you have any idea of

"Joe, do you have any idea of where I might be able to find one. And yes it is the wierd rotor that you describe. DO you have any other suggestions to check before buying the rotor?"
 
"The rotor should still be ava

"The rotor should still be available at any Evirude/Johnson dealership. No, no other suggestions. If I was working on it and had spark dirtly at the coil terminal but not thru the plug wires via the distributor cap, my diagnosis would be a faulty rotor.

I'm assuming that your dist cap DOES have the brush and spring assembled in it."
 
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