Rusty spark plugs

[blacksapphirez]

I replaced them at 10hrs because they were little bit rusty and now at 50hrs, same thing. what is causing it to rust?! Ethanol fuel?!

 

[scokill]

Looks fairly normal. Don't see rust at all.

 

[johhnyboat]

It just looks like carbon from your pics

 

[blacksapphirez]

some sort of corrosion...

 

[blacksapphirez]

Ordered new ones off of Amazon... do these look legit to you? Ones Ive ever had had hash marks in a slant not vertical...and old plug has JAPAN engraved this one does not...

 

[Cobra Jet Steering LLC]

I believe I get iridium plugs in any case if the plug is silver grey then you have something to worry about

 

[tdonoughue]

Can't say I have ever looked in that much detail. However, given supply chain issues these days, they may have changed suppliers or be coming from someplace other than Japan. Personally, I would not worry about it. Install them. If the engine has problems, pull them and put back the old ones (and then complain to Amazon...).

 

[I_squared_r]

China copies NGK plugs and NGK has a guide to spot them. I would only buy spark plugs from a reputable seller. But I always ordered the yamaha oil change kit so there wasn't anything to worry about. As for the color of the plugs, they look fine to me and is only carbon build up.

https://www.ngkntk.com/newsroom/blog/emea/fake-or-not/

 

[blacksapphirez]

update at 80hrs... i've replaced them.

 

[Neutron]

update at 80hrs... i've replaced them.
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Thats really rusty to me. Those plugs were put in at 50 hours and only have 30 have on them?
Is it stored in a very damp environment?
On the water? Salt air?

 

[blacksapphirez]

Thats really rusty to me. Those plugs were put in at 50 hours and only have 30 have on them?
Is it stored in a very damp environment?
On the water? Salt air?

sorry they are the same plugs that was shown in the original post. approx 70hrs on em

I store outside but its very dry and get plenty of sun.

the plugs at 10hrs... (from previous owner, also boat in salt water)

 

[Cambo]

The Mr1 motors had a lot of issues with plug #3 snapping due to being stuck. My theory was that the motor had a tendency to stop in a position that left the exhaust valve open moisture would get in and cause it to rust in place. The water boxes hold a decent amount of water and it could be evaporating and condensating in the cylinder. This is also why it’s important to fog the cylinders. I went to copart to view a boat that had the motor out of the boat and the motor was taken apart sitting in a box next to the boat, the cylinders had a massive amount of rust in them from rain water. For the first start up of the season the boat always pushes water out of the exhaust so there has to be a decent amount of water sitting about 2 ft from the cylinders.

 

[blacksapphirez]

The Mr1 motors had a lot of issues with plug #3 snapping due to being stuck. My theory was that the motor had a tendency to stop in a position that left the exhaust valve open moisture would get in and cause it to rust in place. The water boxes hold a decent amount of water and it could be evaporating and condensating in the cylinder. This is also why it’s important to fog the cylinders. I went to copart to view a boat that had the motor out of the boat and the motor was taken apart sitting in a box next to the boat, the cylinders had a massive amount of rust in them from rain water. For the first start up of the season the boat always pushes water out of the exhaust so there has to be a decent amount of water sitting about 2 ft from the cylinders.

thats actually pretty good theory... I do rinse the motor and do not run for extended period of time, (afraid of overheating) but I should run it a few times before storing so the moisture is "gone"

 

[FSH 210 Sport]

So is this happening to your plugs after it sits stored for a while or does this happen when it’s being used regularly?

 

[blacksapphirez]

So is this happening to your plugs after it sits stored for a while or does this happen when it’s being used regularly?

usually every week/every other week... but this was over 2 seasons too so, i will try to "dry" out my water box from now on

 

[Judge]

usually every week/every other week... but this was over 2 seasons too so, i will try to "dry" out my water box from now on

So a light bulb just came on in my head after reading these latest posts and I just realized that you started the other thread asking people about running in salt water and if they have as much rust as you do in your engine compartment.

If your spark plugs look like this and the engine compartment looks equally rusty, I think I have some bad news for you. You either have a bad head gasket or a cracked block or cracked head.

You likely have salt water spraying into cylinders when running and also spraying out into the engine compartment. You said the boat was never submerged since you bought it with 10 hours one it so this explains why you have rust all over the place in the engine compartment and also see your spark plugs rusting. Salt water spraying into the cylinders and out of the engine explain both of your problems.

How does your oil look? Does it ever get grey or milky? Does the oil level rise at all?

If you have salt water spraying into cylinders, I would be worried about the bottom end of that motor as well as the valve train.

 

[FSH 210 Sport]

IMHO There is something else going on other than the water box not being blown out, but I could be wrong and it certainly won’t hurt to blip it a few times after putting it back on the trailer.

My experience is fresh water, however I’ve never seen any of this type of corrosion on my plugs. I do blow out the water boxes per the manual before winter storage, I do not fog my engines during the off season while the boat is stored in a heated shop-42°- over the winter and I’ve never seen any corrosion on the plugs.

I think it’s cycle springs that puts a tube onto the intake for easy fogging, I’ve seen it on some other members posts.

 

[Cambo]

IMHO There is something else going on other than the water box not being blown out, but I could be wrong and it certainly won’t hurt to blip it a few times after putting it back on the trailer.

Even with revving the motor slightly to blow the water out It does not get it all out. Salt or fresh will not matter if its evaporation the salt is left behind. The combustion chamber is susceptible to corrosion due to the metals that are used and the corrosive gasses left over from normal operation. This motor was left outside for a month from a boat that was one year old I was astonished with how much rust had formed

 

[Judge]

Even with revving the motor slightly to blow the water out It does not get it all out. Salt or fresh will not matter if its evaporation the salt is left behind. The combustion chamber is susceptible to corrosion due to the metals that are used and the corrosive gasses left over from normal operation. This motor was left outside for a month from a boat that was one year old I was astonished with how much rust had formed

View attachment 208059

No way his plugs should look as rusty as they do if he is using the boat every one to two weeks.

 

[blacksapphirez]

So a light bulb just came on in my head after reading these latest posts and I just realized that you started the other thread asking people about running in salt water and if they have as much rust as you do in your engine compartment.

If your spark plugs look like this and the engine compartment looks equally rusty, I think I have some bad news for you. You either have a bad head gasket or a cracked block or cracked head.

You likely have salt water spraying into cylinders when running and also spraying out into the engine compartment. You said the boat was never submerged since you bought it with 10 hours one it so this explains why you have rust all over the place in the engine compartment and also see your spark plugs rusting. Salt water spraying into the cylinders and out of the engine explain both of your problems.

How does your oil look? Does it ever get grey or milky? Does the oil level rise at all?

If you have salt water spraying into cylinders, I would be worried about the bottom end of that motor as well as the valve train.

the oil is absolutely clean. no leak inside.

excess moisture remaining from the waterbox "MAY" be the culprit. bc it still runs fine too