How to check a coil on 1961 Johnson Seahorse 75hp V4SL-13

[Clippership821]

No spark at all. Cleaned the contacts in the distributor cap and rotor. Could it be the wires? Plugs look good. I've got the magneto sitting on the bench. Thinking I might need a new coil. Any way to check old to see it is good. Can these things fail if they get hot? And then work again after cool down?
Thanks

 

[lost1s]

Re: How to check a coil on 1961 Johnson Seahorse 75hp V4SL-13

you got pictures

 

[Chris1956]

Re: How to check a coil on 1961 Johnson Seahorse 75hp V4SL-13

Inspect the coil for cracks. If no cracks, put an ohmmeter on the primary winding. It should have 1 ohm resistance or so. Almost a dead short. Put an ohmmeter on the secondary winding and one side of the primary winding. There should be hundreds of ohms resistance.

Clean and gap the points and check the wiring for abrasion and shorting. Rplace the condenser.

 

[56 rude]

Re: How to check a coil on 1961 Johnson Seahorse 75hp V4SL-13

if you have original coils ,replace them ,it will be just a matter of time before they fail,and usually at the worst time.ive fixed a ton of these old motors and ive not run into any, good old coils. yet.

 

[Clippership821]

Re: How to check a coil on 1961 Johnson Seahorse 75hp V4SL-13

thanks for the responses. Will do. Could this be why I've been having such trouble starting up after shutdown? Hardly ever wants to start back up....

 

[Chris1956]

Re: How to check a coil on 1961 Johnson Seahorse 75hp V4SL-13

56Rude, He only has the one coil inside the dissy. Those last a long time. If the coil doesn't have visual cracks, they are usually good. Hence why I suggested the chgange of condenser and the wiring check.

Make sure both sets of points are gapped correctly.

 

[Clippership821]

Re: How to check a coil on 1961 Johnson Seahorse 75hp V4SL-13

Checked wiring looked good. replaced condenser. Ohmed out the coil. checked then reversed leads... only 1 ohm on each side..... Does magneto have to be on the motor and grounded in order to check spark? Can you spin it and get a spark? thanks