spark plugs and water seperator filter

[RonKMiller]

Hate to go against the grain here, but I have done a lot of motors, not outboards, but just about every other kind and have never used anti-seize on a spark plug in my life! I have never seen it recommended by any mfg of any motor either.

Roger that. I've got a fresh sawbuck sitting right here to anyone that can show a spark plug or OEM motor manufacturer that recommends using it. Like I said, if you feel compelled to use a lubricant (if you suspect future corrosion might be an issue) then half a drop - basically as little as you can put on - of motor oil is more than adequate and should be applied toward the middle-top of the threads where the gasket contacts the base.

Anti-seize can CAUSE engine misfire. It can also alter the heat transfer path and change the heat rating of the plug. A spark plug's main job (besides igniting fuel) is to transfer heat away from the head! IT can also cause loose or fouled plugs. It is also an excellent conductor of electricity and if you manage to get too much on it may contact the electrode and short the plug. This happens ALL the time since most shade tree mechanics think that more is better and glop it on heavy. They then go around scratching their heads wondering why the engine is running worse - since they just did a tune up and used new plugs!

If you're using Marine specific plugs that have stainless steel threads - and you should be - there is NEVER any reason to use it, period.

About the ONLY time anti-seize should be used is if there is a KNOWN ISSUE with a particular engine/plug combination causing galling - and this would apply almost exclusively to very, VERY old antique engines or if the manufacturer specifically instructs the use of it.

(Edited to correct spelling)

[Ron Burgundy]

I've got a fresh sawbuck sitting right here to anyone that can show a spark plug or OEM motor manufacturer that recommends using it.

Bottom of page 3
http://www.mercurymarine.com/media/merc ... Verado.pdf

• Saltwater usage. Remove and inspect spark plugs for corrosion and
replace spark plugs as necessary. Apply a thin coating of Anti‑Seize
Compound only on threads of spark plug prior to installation. See
Maintenance ‑ Spark Plug Inspection and Replacement.
Tube Ref No. Description Where Used Part No.
81 Anti-Seize
Compound Spark plug threads 92-881091K1


I'll take cash or money order.

[GregF]

You beat me to it. I was going to cite the merc shop manual.

I won't even mention the stainless issue but the shop manual also says to use anti seize on all of the stainless steel bolts.

[RonKMiller]

You got it - you have PayPal? Sorry Greg, it's a one time offer only.

And don't forget that I also said "if the manufacturer specifically instructs the use of it." But alas, I can't have it both ways - so you are now $5.00 richer.

I'm REALLY surprised they didn't state a torque value post applying the anti-seize. Generally speaking it is 20% LESS and that is one heck of a lot less twist.

...but the debate goes on!

Interestingly enough, the manual from my 90 hp Yamaha 2 stroke specifically omits it as do the installation instructions from NGK:

http://www.ngksparkplugs.com/techinfo/s ... lation.asp

"When fitting the plug, always clean the gasket surface and use a new gasket. Wipe off any dirt from the threads and screw in the spark plug to the correct torque."

That "correct torque" thing is where lots of owners get into trouble. 95% of general duty torque wrenches on the market do not have settings that will accommodate the 20nm setting - or if they do it is at the very bottom end of the scale and far from accurate. That is an incredibly small amount of torque and just enough to completely crush the gasket and seat the plug. At 10nm you can easily strip a steel fastener mounted in an aluminum casting. It really requires a specialty wrench designed for very small torque loads which are relatively rare and used infrequently by shade tree mechanics. Even with the proper torque wrench it needs to be calibrated on a regular basis in order to be accurate.

My manual further states "... a good estimate of the correct torque is 1/4 to 1/2 turn past finger tight".
You won't get into ANY trouble using this way of installing plugs, and you certainly don't need to rush out and buy a $150.00 specialty tool, or pay $10.00 for a one half ounce tube of specialty spark plug anti-seize.

I still stick by my guns and say that more owners get into trouble by using anti-seize than not using it - and especially by using too much of it. Motor oil is just fine...

[RonKMiller]

But wait - there's more! (I want my $5.00 back, damnit)

Here's NGK's technical bulletin - which directly contradicts Mercury's advice!

Topic
The use of anti-seize compounds on spark plug threads that have a metal shell
plating (i.e. Zinc or Nickel plating).
Issue
Applying anti-seize to the threads of spark plugs that have a metal plating allows the installer to mistakenly over-tighten the spark plug in the cylinder head; This stretches and fatigues the threads of the spark plugs, causing a much higher probability that the plug will break during installation or in some cases upon removal.
Example of 10mm thread spark plug broken during installation due to the use of anti-seize leading
to over-tightening. (Note that plug gasket has been completely compressed, anti-seize can be seen
on threads, and the break is in the direction of tightening).
Solution
For spark plugs with special metal plating simply do not use anti-seize on initial
Installation; All NGK Spark Plugs are manufactured with a special trivalent Zinc-chromate shell plating that is designed to prevent both corrosion and seizure to the cylinder head; Thus eliminating the need for any thread compounds or lubricants.
Additional Information
NGK recommends only using spark plugs with metal plating on all aluminum head applications to prevent damage to the head and plug. Metal shell plating acts as a “lubricant” which breaks away from the main body of the spark plug during removal, preventing damage to the spark plug and or threads in the cylinder head.

plug thread damage.jpg (169.64 KiB) Viewed 2430 times

(edited to highlight thread compound information)

[GregF]

What happened to "stainless" ?

[GregF]

Jesus, I just saw the pictures. Were they putting them in with an impact wrench?

[RonKMiller]

I've got a fresh sawbuck sitting right here to anyone that can show a spark plug or OEM motor manufacturer that recommends using it.

Bottom of page 3
http://www.mercurymarine.com/media/merc ... Verado.pdf

• Saltwater usage. Remove and inspect spark plugs for corrosion and
replace spark plugs as necessary. Apply a thin coating of Anti‑Seize
Compound only on threads of spark plug prior to installation. See
Maintenance ‑ Spark Plug Inspection and Replacement.
Tube Ref No. Description Where Used Part No.
81 Anti-Seize
Compound Spark plug threads 92-881091K1


I'll take cash or money order.

Those instructions are specifically for SALT WATER USE - they certainly don't mention or recommend it for fresh water use. Yeah, I read the PDF.

[RonKMiller]

What happened to "stainless" ?

I can only surmise that when your plugs have the trivalent coating - that NGK says is on ALL their plugs, that stainless - which of course are much more expensive - is not necessary. I still like the idea of upgrading to stainless but I may be just wasting my money. Just like buying iridium and other uber expensive plugs when a good old plain jane variety works just as well...

[RonKMiller]

Jesus, I just saw the pictures. Were they putting them in with an impact wrench?

That's EXACTLY the issue I'm talkin' bout. Add a 20% or more increase in torque due to the anti-sieze and you've taken that 20Nm (14 ft.lbs.) up one heck of a lot. An extra 3lbs. of torque on what is basically a hollow cylinder instead of a solid rod is tremendous!

I'm not making this stuff up - this is right from NGK's techinal bulletin.

[RonKMiller]

drum roll please.... from Champion Spark Plugs - AND - Since Mercury recommends ONLY Champion and NGK... Well, draw your own conclusions from BOTH plug manufacturers.

"Here are a couple of tips to help assure the success of changing spark plugs. The first is to remove spark plugs from aluminum cylinder heads only when the engine is cool. Since aluminum and steel expand and contract at different rates, removing spark plugs from an aluminum cylinder head while hot can actually cause thread and cylinder head damage. Before installing the spark plugs, make sure the threads are clean and in good condition. If in doubt, run a thread chaser through the plug opening in the cylinder head. Champion recommends that you do not use an anti-seize compound, since one has already been applied to the plugs at the factory. Next, install the spark plugs finger tight and, it using a taper seat spark plug, use a ratchet to rotate 1/16 of a turn. If using a gasket seat type spark plug, after installing finger tight, turn 1/4 to 5/8 of a turn. If this procedure is followed, spark plugs will not back out nor will they seize in the cylinder head."

[BiXLL]

WOW, this thread is almost as enertaining as a "WHATS THE BEST OIL" thread! Or we could really live on the edge and start a octane thread!

[GregF]

Since I am in salt water, I think I will follow the Mercury advice. Champion sells billions of plugs and I doubt 0.01% ever get used in salt water.

[RonKMiller]

Since I am in salt water, I think I will follow the Mercury advice. Champion sells billions of plugs and I doubt 0.01% ever get used in salt water.

Yep, I think that makes complete sense.

If applied sparingly, and keeping in mind the dramatically reduced torque requirements, I would do the same as well. I kinda' look at it as "insurance". That's why I like the hand torquing way of installing plugs that Champion talks about versus depending on a mechanical device that is most likely to be REALLY, really wrong.

You can feel the correct "set". The human hand is indeed a miraculous device.

Salt water is tough to deal with - we have similar issues in the Southwest with "hard" water. It causes all kinds of hell with the cooling system and unfortunately there's not much you can do to deal with it except vigilance and an occasional mild acid flush.

[Ron Burgundy]

You got it - you have PayPal? Sorry Greg, it's a one time offer only.

Nah, just take a photo of the sawback and post it here. That will suffice.