How do you know when to replace your spark plug wires? How about the distributor cap?

My wires are probably 10 years old. The cap is probably 5 years old. Everything runs great and looks to be in good condition (no cracking on the wires).

Any hints?

Thanks!

After 5 years, I'd probably get a new dist cap as preventive maintance. As far as the plug wires, if they look good, they're probably ok, but 10 years is pretty old. They could have some small cracks that you can't see.

Wow, I change mine every year. Heres a good way to check them, well I dont know if its a good way but it works. At night, in a very dark place with as little background light as possible, start the engine with the hatch up and look for lightning. If you really want to be sure, spray some water from an old windex bottle around the cap and wires and watch for lightning. I would think 2 years max on the cap and 3 on the wires. But thats up here in the great white north.

Yeah, see, I prefer the hands-on method of checking the wires. I call Dyno to come over and put his hands on the top of the distributor cap while the engine's running. If he makes any wierd sudden jerking motions and vulgarities spew from his mouth I have a clue that one or more wires may be leaking. Seriously, I think you've gotten your money's-worth out of those wires. I encourage people to replace the cap every year and the wires every two years.

Hi CH How ya feeling? I did what you suggested once with my Crane Hi-6 and it almost stopped my heart.

When you talk about changing the cap once a year and the wires every two years how many hours are you talking about? Once a year here in Michigan is different than once a year in Florida for example. Or does the amount of hours you put on your boat have no effect on when to change.
Cardshark

how about ohm them out to the spec in the manual!!!

I have looked at night but I didn't see any sparks leaking. Crazyhorse - thanks for the suggestion but I think I will pass. I am looking for something a little more scientific.

What should a good set of cables read across an Ohm meter?

I would personally guess that some of you guys that are replacing these components every year or two are probably doing so needlessly. These components last for years under automotive conditions that are much more extreme than a marine engine compartment. (Hot headers, water, snow etc) I also agree that a spare cap and rotor never hurts.

Thanks for your imput!

Steve