Spark plugs and Anti-seize

[Cobra Jet Steering LLC]

Remember on new plugs you are compressing the gasket so what I do is tighten the plug and feel for the gasket to compress then I just give it a little more by feel as I said.
The norm is the plugs breaking off usually happen when removing them if the bottom threads of the plug are rusted. This was very common on the tr1 engines.
I run hundreds of hours in salt water with no issues removing plugs or installing them I use regular silver thread locking compound on the plugs because it is what I have available, so doing it with copper or other products should work fine also.
On that If YOU EVER ENCOUNTER A PLUG THAT RESISTE BEING REMOVED!!!! STOP spray C R C or some other penetrating oil in the plug hole, then re tighten the plug just until it hits home and carefully turn it back out until it resists, continue this process until you remove the plug being careful to keep oil in The plug recess so it can go down in the threads. if you force the plug you will break it. Even if you can only loosen it a 1/4 turn at first go back and forth with the oil until it comes out easily.
Now coming to the valves being open when the engine stops etc I believe this is the most logical assumption. remember the water box is a water box. I advised people years ago to un do the hose from the water box to the exhaust manifold and place a heavy plastic barrier between that and the box during winterization to eliminate water vapors traveling back through open valves during long storage. Also I always recommend bumping the starters a few times during long storage to keep from compressing the same valve springs all that time. we all know compressing the springs for extended periods weakens them and also allows for rust to form on the valve stems if exposed to moisture, with all the valves in these engines all it takes is for one to stick when you start the engine up after storage and Bang you hit a valve with the piston and bend it or worse.

 

[Mainah]

I am someone who currently does use anti-seize on both the plugs and plug coil bolts. Based upon the information in this thread I am going to cease using the anti-seize on the plugs amd use only on the coil bolts.

 

[Weeb]

I've seen articles about the whole anti-seize on spark plugs debate that recommend reducing torque by 1/3 of the value. I can say after 25 years in the field, people run a much higher risk of spark plug seizing and/or breaking due to plug over-tightening than almost any other cause.
At the end of the day, it seems like there are a lot more arguments for not using anti-seize on spark plugs, and only one argument for.

As far as torque wrenches go, regardless what brand you opt for, all torque wrenches are notoriously inaccurate at either extreme end of the scale. I personally use an inch-pound torque wrench for most of these lower end torque requirements. 1 ft/lb = 12 in/lbs.

I could be wrong but I was told a long time ago to multiply foot lbs x .88 to get inch pounds. Before that I always thought that 1ft lb =12 inch lbs.

 

[Zizzou 192]

Tools definitely perform better in the middle of their measurement range, even measuring cups.

It would an easy experiment to find out exactly how much extra torque anti seize puts on the plug and would only cost 2 extra spark plugs and 5 min. Next time I'm in there I'll measure it and post my tiny man child misadventure to see if makes no difference, or 10%, 30%, or something else.

If the difference is 10% or even 30% more I would think that it would be moot as 20.2 ft lb or 23.9 ft lb is probably well within the margin of error from 18.4. About 3 ft lb is about what ca be applied to a nut with just fingers and no tools.

The crush lock washer / gasket acts as a kind of built in torque wrench if you do it by feel as most everyone does.

Anti seize also is quite messy and could easily get on the electrode and possibly foul a plug. i have tried not apply it on the first couple of threads to limit that possibility, even though those are the ones that corrode the most

 

[Sbrown]

I could be wrong but I was told a long time ago to multiply foot lbs x .88 to get inch pounds. Before that I always thought that 1ft lb =12 inch lbs.

That would be incorrect. 1 ft/lb is indeed equal to 12 inch pounds.
However, 1 in/lb is equal to .083 ft/lb and that may be where the confusion is coming from.

 

[Bernd]

Just found this in the service manual. Yamaha seems to recommend anti-seize on the plugs.

 

[Stevenpigsooie]

My manual 2016 ar240 doesn’t say that. Might be different for the newer boats?

 

[Bernd]

it's from the 2010 210 service manual under the section periodic inspection and adjustment. Might be different for my MK-1 engine

 

[swatski]

Just found this in the service manual. Yamaha seems to recommend anti-seize on the plugs.

Interesting. That's a MR-1 non-HO. Like @Stevenpigsooie said, new-er 1.8 service manual calls for 18.4 ft-lb torque value and no anti-seize.

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[Weeb]

That would be incorrect. 1 ft/lb is indeed equal to 12 inch pounds.
However, 1 in/lb is equal to .083 ft/lb and that may be where the confusion is coming from.

That’s what I was thinking of thanks. I’m getting older and the memory is not what it use to be.

 

[Cambo]

Going back to the original question on what NGK recommends they also recommend 60-80k milage for spark plug changes . My truck has an hour meter reading 2,300 hours at 70K miles at my current rate of use on the boat about 60hrs a year I will be ready for a plug change in 38 years.

Yamaha states these engines are self draining. Yes the block drains but water sits in the exhaust manifold, water box and water lines take one apart and water will come out. Water is in areas that can freeze and cause no issues because it can expand.

Boats are in in the one percentile of use passenger vehicles do not have standing water sitting one foot from the cylinder and even worse hot gasses mixing with water. The plug threads will get contaminated from just regular plug changes and fogging why not contaminate it with Anti seize. To bad Yamaha did not use anti seize on my seat pedestal bolts salt water use has made them gall up in less than 2 years.

How corrosive is the cylinder with moisture take a look at this 2017 242 e that was on the Copart auction block. This is an extreme example and is good to see why Fogging the cylinder is important . This motor obliviously ingested water but the amount of oxidation build up was incredibility thick . The slightest bit of moisture or condensation can easily create some corrosion

 

[Zizzou 192]

Great inspiration to fog through the plug holes. (which has to be done that way on supercharged 1.8's anyway). I was not expecting that. Did not realize water was being retained there at all.

 

[Jgorm]

I think the most important thing is to blast the water out of the exhaust multiple times until nothing comes out. You need 30+ minute cool down before blasting. I'm mixed on AS on soak plugs. I've only done it once out of hundreds of plugs and i blew out 2 spark plugs on a Ford 4.6 2v. (These are known for this, but still.)

 

[Cobra Jet Steering LLC]

I personally never run the rpm's up on an engine that is out of the water with no load on it . bad for valves and timing chains I just let it idle for a bit to reduce the amount of water in the muffler for towing fast stops can force water back up the exhaust manifold and most engines have a favorite spot to stop at. This spot can leave exhaust valves open to the moisture in the water box to evaporate and then condense inside the combustion chamber.
I also believe in starting the engines on the trailer before use , no load on the started makes that last longer and no load on the engine allows for oil to be circulated again with no load so this is better for the engine while the oil gets spread to the moving parts. I also practice a warm up period for the beginning of any boating day.