Oil fouled plugs at spring commission

Just winterized my boat and fogged the engine. When I complete my spring commission next year and start the engine for the first time, should I leave the old plugs in to burn off the fogging oil then install new plugs? I typically change the plugs before I start it for the first time, but was thinking this may foul the new plugs with oil. Am I being too anal?

Re: Oil fouled plugs at spring commission

Am I being too anal?

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Ayuh,... In my opinion anyways,...

Re: Oil fouled plugs at spring commission

I'd just change them and then start the motor. It will start easier on new plugs plus its easier to work around cold manifolds vs hot ones

Re: Oil fouled plugs at spring commission

Just change the plugs and go to the lake.

Re: Oil fouled plugs at spring commission

larry1167 said:

Am I being too anal?

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I agree with Bond-o, yup, too anal.

I fogged my engine every year, and not only left the plugs in to burn it off in the spring, I left them in the whole summer (and the summer after that, and the summer after that...).


If you have HEI or Thunderbolt ignition, you don't need to replace spark plugs very often.

Re: Oil fouled plugs at spring commission

If you have HEI or Thunderbolt ignition, you don't need to replace spark plugs very often.

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Eagh... dunno how much I can agree with that. Every spring the motor should get a cap, rotor and plugs. Or your going to start having runability issues, usually mid July . And your going to also wonder why your whizzing through coils.

Re: Oil fouled plugs at spring commission

larry1167 said:

Am I being too anal?

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Being Anal is a good thing. Just read 75% of these threads and you'll see why.

Overly Anal is something you need to discern yourself.

Re: Oil fouled plugs at spring commission

I always just remove mine in the spring and turn the engine over a couple of times and put the new ones back in, But I never skimp on the fogging spray especially in the cylinders. It's interesting to read all the winterization posts to get everyones method but changing out the perishables is a must.

Re: Oil fouled plugs at spring commission

JustJason said:

Eagh... dunno how much I can agree with that. Every spring the motor should get a cap, rotor and plugs. Or your going to start having runability issues, usually mid July . And your going to also wonder why your whizzing through coils.

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Oh, my goodness, you have got to be kidding me?! Are you really saying that? Shame on you. I had the same coil, cap, rotor, and spark plugs for 5 years and 355 hours on my 97 5.7LX EFI Gen +. Do you know what happened when I replaced them all? That's right nothing. Starting still took the same amount of time (started right up), fuel economy was exactly the same, top speed was the same, acceleration was the same. In short, the parts didn't need to be replaced. Guess how the boat ran 6 years and 450 additional hours on that same cap, rotor, and plugs. Yep, that's right, PERFECTLY.
Jason, telling people that they should waste their money every spring is not cool at all. You like to say that boating is a rich man's sport, but it's only because of people like you that rip them off. Jeez!

Re: Oil fouled plugs at spring commission

Jason, telling people that they should waste their money every spring is not cool at all.

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I don't think i'm telling people to waste their money at all. If you look at SM 24page 1B-4 it clearly says to "Check spark plugs, wires, ditributor cap and ignition timing. check and adjust idle speed" Every 100 hours or annually.

Since "checking" sparkplugs can be time consuming... old plugs do not get pulled, looked at, and re-installed.
Distro caps and rotors... There is no tool to measure the "wear" of a rotor or cap. The only tool is your eyeball.
If 7 out of 8 studs on the cap look good and 1 is questionable to "my eye" and I say ahhh screw it and ship the boat and the guy comes back with a high speed miss... Well guess what has 2 thumbs and is working for free that day????

This guy. <-----

Same thing for the rotor... can you tell me the specification lengh from the center of the rotor to the end of the tab??? It may be someplace but I haven't seen it in print.

I went to Merc school. It is clearly taught to help ensure a trouble free boating season to change the plugs, cap and rotor every spring. The plug wires are usually good for 3 years before they need replacing. That's straight from a Merc factory trainers mouth to my pretty ears.

Just because you choose not to follow the factory service manual and change parts at a time of your choosing does not mean you are correct. It only means that you have been lucky so far.

Merc doesn't put things in their books because they (or I) want to rip people off. We do the work that is advised so people don't break down on the water.

Using your ideology I should remove fuel filters and flow test them somehow and only replace them if bad, and not at a scheduled interval.

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Jason, please, please, please send me all your 6 month old spark plugs, wires, distributor cap, rotors, and coils. That's what we are really talking about with most boats. 6 month old parts. Please send them to me, I'll provide you my address in a PM and even pay for the shipping. That way, I'll be able to provide them to my friends, for free, and they will have enough quality replacement parts to last a lifetime!

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JustJason, I agree with preventative maint servicing on routine service intervals, but on cars, it is measured in miles... On boats, they want to use hours or time (like annually). Do you really think that a boat that only has 25 hours use in a year needs new plugs, rotors and Dist caps. I don't. You might use your boat enough to warrant changing these items yearly, however, many do not.

Additionally, I would say that there are a great number of companies out there that establish an acceptable service routine, then shorten the schedule just to sell more parts. I am not saying that Merc is one of those companies, but all (cars, boats, lawn equip, etc.) are suspect to me. I think it is trudent to use common sense when replacing these parts. If you can get 70,000 - 100,000 miles on a Dist Cap and Rotor button and a set of plugs on an auto, then why do you think you have to change them yearly (with 100 hours or less) on a boat. Even at WOT for every second running, 100 hours at 40mph is only 4,000 miles. I agree that a boat takes alot more abuse and is under more stress than a car engine, but 4,000 miles vs 100,000 miles is a huge difference...

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Do you really think that a boat that only has 25 hours use in a year needs new plugs, rotors and Dist caps.

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Personally.... Nope(a point set should still be looked at after sitting over the winter though).

But professionally, I go by the book. I have to.

All I can do is advise by whats in the book and let the customer make up their own dang mind.

I hear the question all the time... I only put X amount of hours on the boat this year so do I really need to change this or that. My answer is always the same, it's up to you, however Merc specifies this in their service manuals. By saying that it takes the burden off of me should a failure happen and somebody gets stranded.... say 10 miles off shore.

I do the same thing when I post here to the best of my ability. When somebody asks a question I try to give the best advice I can by the book.

Re: Oil fouled plugs at spring commission

TilliamWe said:

Jason, please, please, please send me all your 6 month old spark plugs, wires, distributor cap, rotors, and coils. That's what we are really talking about with most boats. 6 month old parts. Please send them to me, I'll provide you my address in a PM and even pay for the shipping. That way, I'll be able to provide them to my friends, for free, and they will have enough quality replacement parts to last a lifetime!

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I've always thought we Americans as whole are very wastefull, I'm sure the repair shops throw 6mo old plugs away by the 5gal bucket full, that's one buisiness keeps the other in buisness chain reaction. I'm with you Tilliamwe.

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I do change the cap and rotor each season because I'm in a salt water region and they do get green corrosio on them in one season's time and sitting over the winter...I start up the engine in the spring and burn off the fogging oil...let it run long enough to get good and hot...then shut it off and let it cool down...then remove the plugs and check them. If the look good and are not fouled I check the gap...reinstall with a bit of grease on the threads and run em for another season...I do check the point gap/dwell, timing and idle speed every season and clean the flame arrestor and change the fuel filter...

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I have to agree with BOTH arguments.

The guy that puts just a few hours on his boat on IN-LAND lakes can often safely run the same plugs, wires, caps, etc., for many years.

IF, and that's the kicker, IF anything fails, he merely drifts till someone tows in to the nearest marina.

However, If this boat is out of sight of land in the salt, or adrift down the Mississippi, things could get ugly.

Which is why I tell my customers, it is their decision, they cannot walk home.

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Those who say it is not necessary to change the parts as often as the manufacturer recommends are correct....assuming you are taking full responsibility for that decision when your engine fails on the water. The guidelines set aside are for the manufacturer/service centers to cover their butts should an engine die and leave someone stranded. The FAA does the same thing for aircraft engines/parts. They are only allowed to run for so many hours before they are pulled and rebuilt, regardless of what the compression/troubleshooting checks say. These are SAFETY ASSURANCES.

The guidelines are based upon average life of the parts in poor conditions. Keep the parts in longer and the likelihood of a failure increases dramatically.

Bottom line is the owner can dictate leaving the parts in longer (not on a plane though), but they MUST be willing to assume the responsibility when there is a failure on the water.

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Well put, T-Bone! 'nutcase

Re: Oil fouled plugs at spring commission

T-Bone Coug said:

Bottom line is the owner can dictate leaving the parts in longer (not on a plane though), but they MUST be willing to assume the responsibility when there is a failure on the water.

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Can't really compare airplanes and boats, though. Engine failures in plane result in CRASHES 99.9% of the time. Airplane crashes are very deadly. 90% of the time engine failures in boat cause inconvenience, not a crash, and not death. Sure it happens, but not very often.
So if you are going to compare stuff, compare like things.

You guys go ahead and pay someone to replace pefectly good parts every year, because you lack the knowledge, ability, or time to check them yourself. I know how to do that stuff, so I don't waste my money.

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Plus when I DO change em....I throw the old ones in the box...keep it on the boat...if need be I can easily change plugs and cap n rotor on the water ....also have spare fuel filter...big plastic coffee can to catch any gas...if I had to change that....spare belts too....can basically do a tune up on the mooring if needed but lets face it much better to do it on land....