Hot to test spark plugs and ignition ?

[csaba]

I have a 1973 Johnson 65HP Outboard and I need to test the spark sent from the coils. When I take out the spark plug and hold it a 1/4 inch from the case and crank the engine, a nice and blue spark appears but on 2 of the 3 cylinders, I also seem to get a good shock and if I back it off to 1/2 inch or more then I get a full shock. Since I don't have much hair, there's not much to curl besides a few brain cells ... Are my wires for the 2 cylinders still good ? Whats the easiest/cheapest way to fix this problem ? The wires are attached to the coils so I would have to change the coils according to the parts manual ... ? I can also just buy the boot which attaches to the spark plug. Would this help ?

 

[sho305]

Re: Hot to test spark plugs and ignition ?

I have found this to be normal depending on the moisture in the air and if you are grounded, etc. If the wires are visibly cracked/worn through/damaged/etc., then you should get new or atleast tape them up good if not possible. If the boots look good and fit snug they are ok. I am a firm believer in dielectric compound, especially for the marine environment. A couple of bucks will get you a tube at an autoparts place, and it is like vasiline sort of. Just goo a little up the inside of the boot on the plug and wire end best you can, and it helps keep the energy in there by keeping the air/water out. Keeps the plastic/rubber from drying out too.

 

[leafs]

Re: Hot to test spark plugs and ignition ?

i have a 1974 70hp johnson the mech here said no reason to replace complete coil if just a new plug wire is needed. he says they just screw into the coil