Oil on sparkplug

[Yamaha242lsdallas]

Getting ready to change the spark plugs on my boat today, and I pulled out the plugs on the engine that was put in new by the dealer last year due to a warranty issue. All four of the plugs on that starboard engine had oil all over the threads of the plug. First three had more than the last one. The Portside engine plugs were all dry. Oil levels on both engines are fine, going to be changing them as well. The starboard engine has had it's oil change twice last season. Once for the 10-hour break in and then the 50 hour I think it is, or whatever the normal next service times called for it. Both by me (you would think I'd know the interval )

2 questions, what would cause of this, and should I be concerned about it?

 

[Yamaha242lsdallas]

Also, the oil does look quite dirty even though in the dipstick it doesn't look that dirty.

 

[Cobra Jet Steering LLC]

Was it on just the threads or on the plug body also? I have had sea doo engines that had bad valve cover gaskets allow oil to get in the plug recesses so I wonder if your gaskets are leaking and letting oil in to the plug recesses this part number
Gasket, Head Cover 1

6BH-11193-00-00

 

[Bruce]

Do you think the dealer might have lubed the plugs before installing? Did the dealer only replace the plugs on one engine?

 

[Yamaha242lsdallas]

I picked up the plugs from the dealer and did the service myself, the oil is on the threads only and not on the electrode on the spark plug. I'm thinking it's just a little bit of leakage from the valve gasket. Interesting that it did not show up for my 10 hour break in oil change, but then again I did not push the motor that hard at all at that time in order to break it in per yamaha's instruction.

 

[Yamaha242lsdallas]

I wonder if just checking the torque on the valve cover bolts would help? I have no idea what the torque settings on those bolts are

 

[Yamaha242lsdallas]

Was it on just the threads or on the plug body also? I have had sea doo engines that had bad valve cover gaskets allow oil to get in the plug recesses so I wonder if your gaskets are leaking and letting oil in to the plug recesses this part number
Gasket, Head Cover 1

6BH-11193-00-00

Thanks for the part number, I'm assuming it's not that hard of a project to replace.

 

[Cobra Jet Steering LLC]

if oil is leaking there you should see it if you pull a coil and inspect the plug boot and area around the plug. Or you can just use the boat for a while enjoy it and check on it in a month or so since it isn't any big problem, I bet they just did not use a sealer when they assembled the engine, my 4 tec sea doo would fill the damn sparkplug recesses with oil and it still did not cause any trouble accept when I removed the plug and the oil ran in the cylinders

 

[Yamaha242lsdallas]

It's not showing on the boot itself, just on the spark plug threads. You can kind of see that on the spark plug picture I posted, the oil seems to stop just at the top of the threads.

And thanks for all the input by the way!

I put in a call to the dealer and they are going to see if there is still a warranty on that particular engine since it was newly installed, they're still going to see also if they can just take a look at it at least without cost to me.

Will update, but feel free to add your thoughts.

Thanks.

 

[Cobra Jet Steering LLC]

New engine , rings needed to seat, I do not see any fouling on the plug itself so I would probably run it a while and check on it.

 

[Cobra Jet Steering LLC]

When you removed these plugs were they tight or loose? just wondering how on earth oil would be ONLY on the threads and it's dirty, it looks to me like a small amount was sitting in the plug recess and when you removed the plugs the oil dripped down the threads leading me back to the valve cover gasket slight leak.

 

[Yamaha242lsdallas]

Plugs were snug, not overly tight though. And yes, I'm thinking the same. .i'd replace them right now and see if i get more oil but I only was able to get the Desno 3381. Was told it was an exact replacement for LFR6A but I'm not sure if that's the case, comparison chart shows it is but also lists the LFR6A-11 too.

 

[Cobra Jet Steering LLC]

Well I have no doubt that is all it is , just snug the bolts of carefully and see if it solves the problem .

 

[Yamaha242lsdallas]

I don't want to over tighten the valve cover bolts, anyone know what the torque setting should be on those?

Also when it comes to changing the spark plug does anyone see any issues with using the NGK nickel plugs? They're gapped the same at .036.

 

[bumpy]

I'll look in the service manual tonight or tomorrow and post the torque values. Sorry in advance for the delay; previous obligations!

 

[ruztew]

I pulled this from my 2015 Sx190 service manual.... It's the 1.8l engine, so I'd imagine it's the same torque for all 1.8l engines

 

[Yamaha242lsdallas]

Thanks to you both. I knew the sparkplug torque but was referring to the valve cover bolt torque.

 

[bumpy]

It looks like 5.9 ft-lb. The gasket has a section that wraps each spark plug opening, so this is probably the issue. Good luck!

 

[BlacklimitedS]

A couple more questions:
1 Did you put anything on the threads of the plugs when you installed them like anti-seize?
2 Did you fog the engine and if so did you spray it down the spark plug hole?

I feel if you had a leaking valve cover gasket it would be on the spark plug above the threads as well. Try pushing a rag down the plug hole with a screw driver and see how much oil is on it when you pull it out.

 

[Yamaha242lsdallas]

A couple more questions:
1 Did you put anything on the threads of the plugs when you installed them like anti-seize?
2 Did you fog the engine and if so did you spray it down the spark plug hole?

I feel if you had a leaking valve cover gasket it would be on the spark plug above the threads as well. Try pushing a rag down the plug hole with a screw driver and see how much oil is on it when you pull it out.

No anti-seize, and did not fog. I would have thought the same thing, the oil just on the threads is strange but perhaps because of the "lip" on the gasket it's keeping it off the rest of the plug?

I'll clean out the hole and then with my new plugs and oil change (and making sure valve cover is torqued correctly) I'll keep an eye on it after 10 hours or so.