My first spark plug change did I make a mistake?

[NewBoater]

I just completed my first spark plug change with the NGK spark plugs. I read on here after the fact that you are not supposed to use anti-seize lubricant on the spark plugs. The parts department where I purchased the boat told me to use anti-seize lubricant with the spark plugs so I did. My boat is in the garage for the winter and won’t be coming out and I change the oil and the spark plugs. I put a nice coating of anti-seize lubricant on the spark plugs and then twisted it on my hand until I couldn’t do it anymore by hand with the rich and then I put tMy boat is in the garage for the winter and won’t be coming out and I change the oil and the spark plugs. I put a nice coating of anti-seize lubricant on the spark plugs and then hand twisted until I couldn’t go any further and then applied a wrench and went 3/4 of a turn extra on each one. It felt like it should’ve been tight enough with a half turn to me but they told me to do 3/4 of a turn and that’s what they do at the parts department when they are changing the spark plugs on Yamaha jet boats. Now I read you are not supposed to use anti-seize lubricant because you can over tighten. Should I go back and loosen each one a quarter of a turn or just leave them be until the spring and hope for the best? Thanks for any advice. Here’s a few pics of the old plugs.

 

[Luc Lafreniere]

3/4??? Are you sure they didn't say 1/4??? Because I'm pretty sure it's 1/4 or proper torque with a torque wrench. I wouldn't worry too much about the antiseize, I'd be more worried about turning it 3/4 of a turn.

 

[Liftr]

I used my Search Engine Kung Fu, and found this article from NGK:

NGK spark plug instructions

“
Without a Torque Wrench:
If a torque wrench is unavailable, finger tighten the spark plug, then use a plug wrench to tighten.
Autolite -For spark plugs with a gasket: 1/4 turn on 10mm plugs, 3/8 turn on 12mm plugs, 1/2 turn on 14mm and 18mm plugs. 1/16 turn on plugs with a tapered seat.
Bosch - 1/4 turn on plugs with a gasket. 1/16 turn on plugs with a tapered seat.
Champion - 3/8-5/8 turn on plugs with a gasket. 1/16 turn on plugs with a tapered seat.
Denso - 1/4-1/2 turn on plugs with a gasket. 1/8 turn on plugs with a tapered seat.
E3 - For spark plugs with a gasket: 1/2 turn on 10mm plugs, 3/8-1/2 turn on 12mm plugs, 1/2-3/4 turn on 14mm plugs. 1/16 turn on plugs with a tapered seat.
NGK -1/2-2/3 turn on plugs with a gasket. 1/12-1/8 turn on plugs with a tapered seat.”



FWIW, I did mine similar to what you did. But stopped at 1/2 turn.

 

[NewBoater]

I used my Search Engine Kung Fu, and found this article from NGK:

NGK spark plug instructions

“
Without a Torque Wrench:
If a torque wrench is unavailable, finger tighten the spark plug, then use a plug wrench to tighten.
Autolite -For spark plugs with a gasket: 1/4 turn on 10mm plugs, 3/8 turn on 12mm plugs, 1/2 turn on 14mm and 18mm plugs. 1/16 turn on plugs with a tapered seat.
Bosch - 1/4 turn on plugs with a gasket. 1/16 turn on plugs with a tapered seat.
Champion - 3/8-5/8 turn on plugs with a gasket. 1/16 turn on plugs with a tapered seat.
Denso - 1/4-1/2 turn on plugs with a gasket. 1/8 turn on plugs with a tapered seat.
E3 - For spark plugs with a gasket: 1/2 turn on 10mm plugs, 3/8-1/2 turn on 12mm plugs, 1/2-3/4 turn on 14mm plugs. 1/16 turn on plugs with a tapered seat.
NGK -1/2-2/3 turn on plugs with a gasket. 1/12-1/8 turn on plugs with a tapered seat.”



FWIW, I did mine similar to what you did. But stopped at 1/2 turn.

Thanks so much for the info. 1/2 turn felt right to me but since they said 3/4 I went a little bit further. Do you think I should take them back a quarter of a turn on each one or just let them be? Thanks

 

[Beachbummer]

No harm in anti seize.

I would not loosen the plugs now. Just change them next year when they are due. I humbly think there is more wear and risk by messing with it than by leaving it alone based on what was already done. It's good enough and close to perfect, minus the overtighten, but what is done is done. This is a complex/variable area that most handle by feel, but torque wrench can help. Tight enough the plug does not back out, but gently enough you don't damage the threads.

Sounds like the boat is just fine.

Enjoy!

 

[ADoyle3]

Don't worry about the anti-seize.. I agree with Beachbummer..Don't adjust them at this point. I would run the normal lifespan on the plugs. Let them heat cycle. Should be fine. The fewer times you stretch and compress the threads in the cylinder head the better! The plugs you pulled look in good shape. They will last a LONG time in an engine that runs properly and does not burn oil....

 

[NewBoater]

So I should be looking at replacing them every other year not every year I would assume? These old ones were from not last fall but the fall before that and you say they still look pretty good. I’m guessing every year would be overkill?

 

[Cobra Jet Steering LLC]

I use never seize on the plugs when I being home a new Yamaha before it hits the water I remove the plugs never seize them and hand tighten the plugs by feel never use a torque wrench if you use never seize. I then place dielectric grease on the plug boots at the coil to prevent the boots from sticking to the plugs then I spray all the clamps and the entire outside of the engine with white lithium grease. This is prior to ever letting it touch the water and I now have over 760 hours of salt water use was out all day today as a matter of fact. So everyone may have their own ritual I think your plug install will be just fine.

 

[Beachbummer]

@Cobra Jet Steering LLC

How do you know they are tight enough? I have had plugs become loose in boats before, I use the torque wrench when I have it now, or do my best to tighten to prevent back out by giving a quarter turn after it gets just tight, when I forget the torque wrench.

I like the torque wrench because there's no feel error possible. It clicks, and that's that.

 

[swatski]

Hand-tight, then 3/4 turn - is what I have been taught to do.
No anti seize for me. Anti-seize is fine, especially if not changing plugs too often, and certainly in salt. Just don't use a torque wrench.

@NewBoater your plugs should be fine!

--

 

[Cobra Jet Steering LLC]

Interestingly with never seize on the plugs if you did try to torque it to specs you would go way past the real torque and very possibly break the plug i never had a plug issue, you tighten it and then go a bit further using a regular ratchet wrench .

 

[Cobra Jet Steering LLC]

By the way especially in the case of a M R 1 engine those were really bad having a big bad reputation of breaking off the number 3 plug when trying to remove it and this becomes a huge issue for the boat owner so The 1800 engines have also had issues trying to remove a plug and breaking it off in a cylinder, do a search.
Lessons are expensive unless you learn from other peoples mistakes.
Remember exhaust valves stay open when a jet engine is turned off, just depends where the cams stop and newer engines have a couple exhaust valves per cylinder, the exhaust side of the engine is directly connected to the water box "MUFFLER" while the boat is not in use, water evaporates and rises up the exhaust system then condenses in the open cylinder, most engines have a habit of stopping in a particular position thus allowing more condensation to enter the same open cylinder more often than others.
The plug body threads past the head and may expose some of the bottom threads to this moisture causing that thread to rust. when you try to remove it the rust binds up in the threads and usually the person removing the stuck plug applies sufficient force to the wrench to snap off the end of the plug . NOW you have a big problem ! There are ways to remove a stuck plug without breaking it but that is a lesson for another day.

 

[Beachbummer]

I've done ok with the torque wrench. The specified torque is extremely low. So far so good.

 

[Zeusmotorworks]

Having come from an aerospace manufacturing background and having had my own rally car company, I don't know if I have anything to add to this conversation. What the hell, I'll take a stab at it.

Not only is there nothing wrong with using a torque wrench with antiseize, but I would HIGHLY recommend it for the average Joe who has not been "calibrated" with years of experience. Also, I HIGHLY recommend antiseize as these are very small plugs and over time with or without salt water you have two dissimilar metals in contact with each other under significant heat. This can cause seizing and galling of the threads. If you don't know anything about chemical reactions between dissimilar metals, google it. (if you're thinking to yourself that you've never had a problem not using antiseize, also understand that there are people who never used condoms and don't have HIV or anything "itchy/burny". Don't know it's worth rolling the dice but to each their own.) Many, many of the aeroframe parts I built are still in service today and many of you have ridden in aircraft equipped with them. Most have something on the threads of threaded fasteners. At the very least, an epoxy primer to combat the aforementioned dissimilar metal reaction. Granted, those are not generally removed with any frequency, but your mileage may vary.

HOWEVER!!! Depending on what antiseize compound you use, it can (generally will) change the torque value anywhere from minimally to substantially! So you have to be very careful in selecting your torque value, and are on your own in that venture. If you don't want to contact the compound manufacturer for a recommended "starting point", I'd say start low and watch for the "1/2-3/4 turn". I won't make a recommendation past that.

To NewBoater's question. If you want to be overly cautious because you are afraid of the effects of expansion on over torqued threads when the engine is heated up again, swap in a fresh set with less torque. I mean really, what does it cost. On the flip side, you may be fine as is.

 

[Looper7]

Interestingly with never seize on the plugs if you did try to torque it to specs you would go way past the real torque and very possibly break the plug i never had a plug issue, you tighten it and then go a bit further using a regular ratchet wrench .

Not true dry threads cause problems specially in aluminum proper torque and anti seize is the safest I'm new to boating but have spent the last 30 years making a living in motorsports and have NEVER broken a plug

 

[Ratket]

I have broken plenty oh shit through over tightening.. I tend to be very ginger and not use anything that gives me “ to much leverage”.. and use only 1 hand. This is my personal preference as every person and situation is distinctly different.

 

[Cobra Jet Steering LLC]

And so we now have a multitude of opinions, all you need to do is choose what one makes sense to you I know what I have been doing and it certainly works well for me but I have been working on cars, race cars, motorcycles and boats over half a century.
As for dissimilar metal causing the problems In this case I strongly disagree, Yamaha places an anode inside the water jacket of the engine to deal with that and especially on the mr1 engines it is almost always the number 3 cylinder that breaks the plug when removing it.
I have seen a lot of dissimilar metal corrosion over the past decades and the plug issue is in my opinion a water vapor issue.
So good luck but in my opinion I would just leave the plugs the way you have them, like I said I follow a ritual on this and have clocked thousands of hours in salt water use.

 

[Billtex2000]

Changed mine a few weeks ago when I put her to bed. Anti-seize and 1/4 turn past hand tight. Same as every year.

 

[NewBoater]

I will leave them as is guys, I appreciate all of the opinions! Next fall I will probably only do a 1/4 to half turn when I change them at the end of next year. Thanks again

 

[Zeusmotorworks]

And so we now have a multitude of opinions, all you need to do is choose what one makes sense to you I know what I have been doing and it certainly works well for me but I have been working on cars, race cars, motorcycles and boats over half a century.
As for dissimilar metal causing the problems In this case I strongly disagree, Yamaha places an anode inside the water jacket of the engine to deal with that and especially on the mr1 engines it is almost always the number 3 cylinder that breaks the plug when removing it.
I have seen a lot of dissimilar metal corrosion over the past decades and the plug issue is in my opinion a water vapor issue.
So good luck but in my opinion I would just leave the plugs the way you have them, like I said I follow a ritual on this and have clocked thousands of hours in salt water use.

Not to drag this out, because NewBoater has his plan. However, I’m a little confused. You promote the use of anti-seize, and it seems you misunderstood my statements about dissimilar metals as if it were being put forth as the culprit of a situation NewBoater had not addressed nor experienced. I was merely stating my reasoning for using a compound on the threads between the steel plug and the aluminum head. What’s more, the anode would do nothing for those two in direct contact as they are not underwater nor inside the water jacket.

My statement about using a torque wrench with a compound (essentially a lubricant to the torque surfaces) was laced with caution. Due to the fact you pointed out. Your torque value would increase due to the “lube” involved. Having been a trainer of many disciplines for over a quarter century, most inexperienced monkeys behind a wrench fair better with a torque wrench (if they know how to use it) than their inexperienced speculation on “feel”.