5.7L spark plugs

[Phlorida]

I had my mechanic swap out my spark plugs when he did my annual last week and they made such a difference I'm convinced that I should do that annually. The plugs that came out looked fine and had been replaced two years ago. I took the boat out this morning and the fresh plugs raised the idle back to normal and the WOT RPM returned to 4800 from 4600. Other than adding $50 to the cost of my annual maintenance I can't think of any reason not to do this. Any thoughts? Perhaps I am the only one that doesn't do this.

 

[psubill78]

Interesting... Unusually go a few seasons on a pair.... Curious to see what others do.

All this maintenance -- and I've never changed them on my cars lol

 

[Lazy Daze]

Were the old ones gapped correctly? Maybe one of the plug wires wasn't seated properly? Unless there was something wrong with the old plugs, I doubt that just the fact that new ones were put in changed things.

 

[Phlorida]

Thanks for your guidance Dennis! I am interpreting your response to mean that the plugs should be fine after two years.

I didn't check the gaps I only looked at them and the burn looked normal and identical across all eight plugs. The plugs were new in March 2011 and the idle was perfect as well as the WOT was 4800. I had noticed recently that the WOT had dropped to 4600 and that the cold idle was too low. When I mentioned it to the mechanic he suggested plugs and indicated that two seasons (230 hours) was about all that he recommends. He said that the cap and rotor looked fine. The only other changes to the boat were oil, filters and drive fluid. This is the same mechanic that replaced the plugs in 2011. The problems with the WOT and the idle did go away after this work.

 

[Lazy Daze]

I would say that it is not the "norm" for plugs to be causing that issue with only 230 hours on them. I'd still mean towards thinking that something else was slightly off and was "fixed" just by removing/reattaching wires. But who knows - nothing's really normal when it comes to boats!

I definitely wouldn't recommend, as "standard practice" anyways, replacing plugs after 2 years. But for whatever reason, it worked for you and was an inexpensive (in boat dollars, anyways) fix.