Spark plug...now I am worried!

[CDENsomnia]

Guys, Thanks for the detailed thoughts on this subject. To some degree it makes me feel a little better knowing what you all do or don't do to prevent this corrosion. The last thing I want on my 40k dollar boat is corrosion. I will definitely alter my maintenance schedule, use the anti-seize and stabil a little more frequently. Fogging will most definitely be added back on the to do! Again, thank you all for the thoughts on this subject...I got pretty sick pulling that spark plug and seeing corrosion...then just waiting for the milky oil! Luckily the milky oil never came.

 

[davel501]

I had the same rust on my plugs last season. I have not changed them yet this year. Interestingly, the rusty plugs were the first ones I had used anti-seize on. I did not use the anti-seize when I changed the plugs last based on the bulletin from NGK that said it led to overtightening of the plugs. I now use the T-handle spark plug wrench included in the tool kit to just crush the washers. I use only marine grade gas that is guaranteed for 1 year: http://www.valvtect.com/marineFuelGasoline.asp

 

[Zeus2013]

I heard no anti-seize strictly due to possible over torque of the plugs. I could not find any other reason listed anywhere.

 

[maboat]

. I spray the entire engine with Boeshield T-9 every year before it goes into winter storage. It displaces any moisture that may possibly be present and forms a wax like coating. Be careful around aluminum, it doesn't play well together.

I wish I had started using Boeshield sooner. There are a bunch of steel hose clamps that aren't stainless and very corroded just from moisture (I've never had a flooded engine compartment). But @Glassman what do you mean about not playing well with aluminum? Isn't the most of the whole engine aluminum? Boeing puts a lot of aluminum in airplanes, so I'm confused about using Boeshield now.

 

[maboat]

Stuff rusts. Boats are in water. The exhaust is both an oxidizer as well as added moisture in there from the cooling system. Exhaust valves remain open, at least one of them, per engine. And spark plugs have steel threads that go in an aluminum block. All of this will continue to reinforce my belief that anti-seize on the spark plug is a good thing, along with annual spark plug changes at a minimum. I will continue to use standard plugs, not iridium's, anti-seize, and the practice of 1/4 to 1/2 turn past hand tight instead of using a torque wrench. If you use anti-seize, you can't really use a torque wrench, because the values are way off IMO, as the plug will turn in much easier with the grease than without it.

This is my thinking too. Antiseize, finger-tight, then another 1/2 turn.

 

[rkluck]

Last weekend I changed the plugs and the plugs looked good with no rust. I did use anti-seize and then a 1/4 turn past hand tight.

 

[txav8r]

I don't think you can over torque a spark plug doing the hand tight on the extension and then put the ratchet on it and only go 1/4 to 1/2 turn. It will be snug, stop any loss of compression, and prevent any moisture from getting in or out. And they will come out easy. @Glassman...@maboat and I both want you to finish your sentence about aluminum not playing well with...I am guessing dissimilar metals.

Also, @CDENsomnia , don't worry at all about the spark plug corrosion. It isn't rusting your aluminum block. But you don't want that doing that long term...it will hold a spark plug eventually and one will break...even one of the bigger ones!

Don't you guys love this forum? I do! I appreciate every one of these discussions, even when I don't agree with it completely! I still learn something every day!

 

[justason]

Image of my plugs pulled last fall at the end of boating season. I had taken water into the cylinder, chore to dry out, I'm thinking I had some residual moisture in the spark plug well that caused this. the threads and base are fine. These plugs did go to Bimini and back, but I don't think that's a factor.
I install hand tight plus 1/4-ish with anti-sieze.

 

[ToddW850]

Image of my plugs pulled last fall at the end of boating season. I had taken water into the cylinder, chore to dry out, I'm thinking I had some residual moisture in the spark plug well that caused this. the threads and base are fine. These plugs did go to Bimini and back, but I don't think that's a factor.
I install hand tight plus 1/4-ish with anti-sieze.

View attachment 4991

Holy Crap! That doesn't look good (in case you didn't know). At least the worst corrosion is on the top of the plug and not the bottom (nside the engine). But with the spark plug cover insalled, I'm surprised it was able to reach the plug. That's interesting.

 

[justason]

Holy Crap! That doesn't look good (in case you didn't know). At least the worst corrosion is on the top of the plug and not the bottom (nside the engine). But with the spark plug cover insalled, I'm surprised it was able to reach the plug. That's interesting.

Ya, I shook a little when I saw it....then when it was all exterior I felt a little better and pieced it together......... I'm still a little perplexed, don't know how it got wet in the first place.

1 of the 4 is in fine shape. that cylinder never got wet, others were at varying levels of wet. #3 was the wettest......

 

[Glassman]

I wish I had started using Boeshield sooner. There are a bunch of steel hose clamps that aren't stainless and very corroded just from moisture (I've never had a flooded engine compartment). But @Glassman what do you mean about not playing well with aluminum? Isn't the most of the whole engine aluminum? Boeing puts a lot of aluminum in airplanes, so I'm confused about using Boeshield now.

Sorry Mark, I should have elaborated. You CAN use it on aluminum, just be careful on the finish type - think of it as a cleaning oil, use it and wipe it off. I've used it with a mild scotch brite pad to clean my tower, then I use either Mother's or Flitz to semi polish and protect.
Don't leave it set on polished aluminum, unless you want to polish it again. On the other stuff it's fine. It won't eat the aluminum like an acid would.

 

[Murf'n'surf]

Simple green in concentrated form will do the same to nice shiny aluminum rims! Ask me how I found out

 

[ACRDSPORT14]

I removed one spark plug today to see what it looked like after my first year of winterizing. I did it my self last fall. Looked 100% perfect, started right up and didn't smoked at all. I fogged it threw the breather port and threw each spark plug pretty good too.

 

[Captbob]

This was on the NGK web site. See attachment.

 

[Captbob]

This is a better format.

 

[txav8r]

This is a better format.

And yet, spark plugs have been breaking off in yamahas for years. I agree that the plugs in the newer boats are less likely to break, but they are not less likely to seize. If you torque to spec using anti seize, you most certainly will over torque them. However, hand tightening. And then torquing an additional 1/4 to 1/2 turn won't. I have read that bulletin and view it as disclaimer to liability on spark plug failures that have been going unanswered for years. And the plugs in the previous boats were also coated...and seizing way too frequently without the use of anti seize.

 

[davel501]

It was my irridiums that had the rusty plug. Maybe my research found a plug that matched everything except the special coating. Went back to stock plugs last year and will be swapping them soon so will have to update.

 

[Captbob]

And yet, spark plugs have been breaking off in yamahas for years. I agree that the plugs in the newer boats are less likely to break, but they are not less likely to seize. If you torque to spec using anti seize, you most certainly will over torque them. However, hand tightening. And then torquing an additional 1/4 to 1/2 turn won't. I have read that bulletin and view it as disclaimer to liability on spark plug failures that have been going unanswered for years. And the plugs in the previous boats were also coated...and seizing way too frequently without the use of anti seize.

I have to agree. In our society today where litigation is for profit and deny everything, even when guilty, is the name of the game, the manufactures disclaim everything. Look at GM. I tow with a 2003 Expedition which has 33,000 miles on it and I was going to replace the spark plugs since they are 11 years old. Everyone has told me not to do it myself and let the dealer do it. The chances are that the plugs are frozen in place.

 

[txav8r]

They say not to use anti-seize on the lug nuts on your trailer too. But if you don't, you may have issues changing a flat if you have to. We immerse these things in water, or they live around water, and they rust. Prevention of rust is important. The main thing to remember is the torque settings will be off if you use anti-seize, and you don't want to over torque anything.

 

[Magic]

This is good info guys! I use anti-seize on the lug nuts, but since the plugs have crush washers, I have found that hand tight plus 1/4 turn fells like it seats them without over-tightening...... Never knew torque specs would be off from using it!