Cleaning Spark Plug Holes?

[ncnmra]

I recently did a compression test (seems normal) and in doing so noticed that there is a lot of "gunk" in the spark plug holes. I'm not sure if this is built up anti-seize or what, but it is concerning as during the process of removing/installing spark plugs I'm concerned that some of this crap could fall into the cylinder.

Is there any way to clean this? I don't want to start scraping it with the plug out for obvious reasons. Some of it looks "crusty" and dried on. Starboard was worse than port for some reason.

 

[itsdgm]

What comes to mind right away would be to insert an old spark plug to cover the hole and then use a toothbrush and a tiny suction tip on a shop vac. I bought a small tip for the vac at lowes. After that I might try to spray a tiny bit of we/40 and use a rag to soak up the leftovers. I'm sure others will have a better ideas though

 

[jameskeller76]

First thing to do is put the plugs back in before anything falls into the cylinders. Secondly I wouldn't concern myself with cleaning it. But it you think you really want to you could fill them up with carb cleaner, let it set and then vacuum it out. Note, you would do this with plugs in tight.

Personally I would leave it and use pressurized air to blow them out before you remove the plugs next time.

 

[ncnmra]

Yes, but there looks to be a good amount of "crud" right under the ring where the plug sits. I'm concerned that this could cause compression loss over time, and/or it could come out later.

I'm tempted to find a bolt with the same thread pattern as the plug to screw into the hole to plug it, add carb cleaner or other degreaser, and then use a long q-tip or similar to scrub it out, vacuum, let it dry and then remove the bolt again. Dumb idea?

 

[jameskeller76]

Yes, but there looks to be a good amount of "crud" right under the ring where the plug sits. I'm concerned that this could cause compression loss over time, and/or it could come out later.

I'm tempted to find a bolt with the same thread pattern as the plug to screw into the hole to plug it, add carb cleaner or other degreaser, and then use a long q-tip or similar to scrub it out, vacuum, let it dry and then remove the bolt again. Dumb idea?

I honestly don't know. Seems any bolt would still cover much of what you are trying to clean and I would be leery of threading anything except a spark plug into it. Was the boat running OK?

 

[ncnmra]

Yes, boat is running OK. I have slightly lower (~200) rpm lower port vs starboard, but I don't think it has anything to do with this. My concern was over the longer term of removing plugs, etc and something eventually falling in. The starboard side looks like it may have some dried oil, perhaps the previous owner used oil instead of anti-seize to lube the plugs: not sure.

My thought of using a bolt, was to buy one long enough that only the threads would go into the plug hole, and the head would stick out far enough to avoid covering the part I wanted to clean. Basically thread it in barely just to ensure no crap goes into the hole. Not sure about what thread the plug is though.

I thought that someone would have a better idea, or that there may be a tool for this specific job.

 

[mrmeaniemeateaterman]

We should make this thread into a Yamaha commercial:

Yamaha boats are so low maintenance, owners are concerned about the spark plug holes being dirty.

 

[ncnmra]

We should make this thread into a Yamaha commercial:

Yamaha boats are so low maintenance, owners are concerned about the spark plug holes being dirty.

Normally, I wouldn't be so anal, but in this case, I have serious concerns of this stuff falling into my engine at which point it isn't "low maintenance". Two of the spark plug holes on the starboard side look like they actually have a bit of crusty oil inside there. This was the first time I'd personally looked down there, I haven't taken the plugs out before.

 

[AZDANSX230HO]

I recently did a compression test (seems normal) and in doing so noticed that there is a lot of "gunk" in the spark plug holes. I'm not sure if this is built up anti-seize or what, but it is concerning as during the process of removing/installing spark plugs I'm concerned that some of this crap could fall into the cylinder.

Is there any way to clean this? I don't want to start scraping it with the plug out for obvious reasons. Some of it looks "crusty" and dried on. Starboard was worse than port for some reason.

View attachment 45712 View attachment 45713 View attachment 45714

With the plugs in, wrap a rag around the end of a screw driver, spray rag with some carb cleaner, then wipe around the plug and get out as much gunk as possible. Then remove the plug and as Dennis recommended vacuum out any loose debris. Then get the rag and screwdriver in there again and keep cleaning until satisfied. You will have to pull the rag out and re-position on the screwdriver numerous times so you are always working with a clean portion of the rag.

 

[Wayloncle]

I wouldn't try to thread a bolt in there, mess up those threads and you will have some much bigger issues!

I've never really checked (never needed to) but aren't spark plugs kinda like pipe threaded? Tapered a little?

 

[ncnmra]

I wouldn't try to thread a bolt in there, mess up those threads and you will have some much bigger issues!

I've never really checked (never needed to) but aren't spark plugs kinda like pipe threaded? Tapered a little?

That's why I ask. Again, I wonder how this is handled "professionally". What would be the repercussion if some of the dried oil (assuming that's what it is) actually fell into the cylinder? Wouldn't it get blown out the exhaust? I'm sort of scared to change out the plugs now based on this.

 

[Bruce]

I can't imagine that dried oil would cause any problem in the cylinders. Metal shavings or rocks would be bad but dried chunks of oil are just going to get chewed up, burned up or thrown out.

 

[Wayloncle]

That's why I ask. Again, I wonder how this is handled "professionally". What would be the repercussion if some of the dried oil (assuming that's what it is) actually fell into the cylinder? Wouldn't it get blown out the exhaust? I'm sort of scared to change out the plugs now based on this.

If I noticed stuff in there I'd put the plug in and blow the crap out with an airhose.
IMO, if the stuff actually fell on down into the cylinder, as long as it isn't a rock or piece of metal, it isn't going to do any damage. If it's just some gummed up oil or a little anti-seize it'll just get burnt up and blown out with the exhaust....again Just my opinion, I wouldn't stress over it.

Edit. Guess Bruce and I were typing the same time

 

[ncnmra]

Oye; ok from what I read, the sparkplug is a "standard" M10x1.0 (ultra fine) pitch. Of course, I would try to thread a M10x1.0 nut on the plug first, but that is going to be hard to find. My "ideal" would be to find a long nylon threaded rod with M10x1.0 threading, use that to plug the hole, and then do the trick with the carb cleaner soaking/small brush/vacuum/compressed air to get it all out. That sounds like a fine idea, but I can't find M10x1.0 nylon threaded rods anywhere. I wonder if I could tap one myself?

 

[ncnmra]

I intend to do the recommended carb cleaner trick with the plugs in first....but there looks like there is a good amount of dirt in the area under the plug ring, so that will require some more attention potentially.

 

[Chip F.]

Take a look , maybe adapt what's done to what you want to do and unscrew the spark plug until only two threads are in?

 

[veedubtek]

Once you're done with whatever method you try, crank the engine without spark plugs installed. If anything fell in there, the compression will blow it out.


<tinyfont> and don't use anti seize on your spark plugs!!! </tinyfont>

 

[Bruce]

and don't use anti seize on your spark plugs!!!

Why not use anti seize?

I use Optimoly TA. Figured if it was good for spark plugs going into aluminum Porsche heads it would be good for aluminum Yamaha heads as well?

 

[veedubtek]

It's not needed anymore to put it simply.

To expand a bit, spark plugs are nickel plated these days to prevent corrosion. It screws up your torque readings when installing. And, most importantly, completely ***** up all the heat dissipation properties a spark plugs NEEDS to have.

Is it gonna hurt you? Eh, *probably* not. Is it gonna help? 100% guaranteed NO.

 

[Bruce]

@veedubtek, if I don't use it on the boat I will never have any chance of using up that tube of Optimoly TA!

On a serious note, the #3 plug on MR-1s has a bad habit of breaking off in the cylinder. I thought a light coating and annual changes might help to avoid that catastrophe.