1979 100 HP Johnson Test coils

[bojango541]

Hello, I have a 1979 100 HP Johnson. The compression is low on all 4 cylinders and there is no spark on 3 of the 4 cylinders.

It seems to me like 3 of the coils are bad. Is there a way to bench test these so I can confirm my suspicions? I am going to part the motor out on ebay and want to be sure it is the coils that are bad so I don't send anyone a bad part.


Thanks!

 

[boobie]

Re: 1979 100 HP Johnson Test coils

Go to CDIElectronics.com. They should have the Ohm specs. The only proper way to test a coil is with a load tester. Some dlrs may still have them.

 

[emdsapmgr]

Re: 1979 100 HP Johnson Test coils

You can swap the supposed 3 bad coils one at a time with the known good firing one. Crank the engine. See if you have spark. That will give you an indication of whether they will fire or not. Usually these coils are fairly reliable. Would be unusual for all 3 to fail at the same time.... The original coils on these early engines have been replaced/superceded with newer style coils with plug-in high tension wires. Not sure you will get much salvage value out of the original ones.