Spark Plug Wires ???

[amanphoto]

I need a tie breaker.

The issue...
I have a 1999 Carver Mariner 350 with Mercruser Gas engines (300 hours in fresh water). Last summer the engines would not rev very high. It started great and idled great. The problem turned out to be old and crusty spark plugs and distributor. After gaping 16 new plugs and fighting in the tight spaces around the engine and fuel tank, I was able to replace them. The boat runs great now. My car mechanic said not to replace the wires. Reason - the new stuff is crap and don't contain as much copper as the old wires and are lesser grade. My boat mechanic said to replace the wires just because they are old. They are not arcing. They don't show any discoloration and are still very pliable. There is not corrosion on the wire caps.

What is your opinion?

[bud37]

I would inspect them close for nicks and pinches and check the ohms, if ok leave em.......Heh a question related to the plugs, this I have to do on the same boat....how long did it take and any special tools / mods...thanks......

[Viper]

If she's performing as she should after the tune-up, then they're probably fine. Having said that, they're now 19 years old. As far as new wires are concerned, I haven't had any issues with OEM wires, I use them all the time and they'll probably still last 20 years.

[tomschauer]

I would vote to replace the 19 year old wires. The new ones are just as good if not better than the old. After 19 years in an enclosed area exposed to some pretty high heat, its time to go. Wires can be finicky, you can have a bad spot on a single wire that may be fine 95% of the time, and then, under a certain load or temp it will arc to ground causing a miss that will drive you nuts trying to find.

[feeez]

Source of the post I would inspect them close for nicks and pinches and check the ohms, if ok leave em.......Heh a question related to the plugs, this I have to do on the same boat....how long did it take and any special tools / mods...thanks......

Keep a pack of bandaids handy for your knuckles......



Cheers
Fraser

[waybomb]

Tip - at night, no lights on anywhere, start the engines and look for a glow around the wires or even faint sparks.
If you don't see anything, probably a-ok.

If you have a bent for pain, start em up and start grabbing wires. You'll find any current leakages pretty quickly.

edit - if they are this far gone, you have a big safety problem. I change my wires every 5 years of so, and buy OEM sets, not cheap knock-offs.

PV gets really good wires, probably overkill. Don't need those for the Carver.

[mjk1040]

Ain't broke, don't fix it. Spray bottle with H2O will find a bad wire too!
Seen new spark plugs that are bad!

[dcrahn]

The car mechanic who said new wires are crap, has obviously been living under a rock. 19 year old plug wires are crap. Replace them and your engines will love you for it, especially the coils. It's all about resistance per foot Even a cheap set should perform better than the old ones. I personally prefer MSD 8.5mm Super Conductors. Just put a set on the new engine I built going into my boat. Mind you they're not cheap, but worth every penny you pay.

[mjk1040]

Curious, do u think the spark plugs u replaced were the original? Did they have engine paint on them. My guess they were. Crappy fuel will crust plugs. Guess if everything is original and I was doing a tune up I'd do it all, plugs, wires, cap & rotor!