Black Spark Plugs

[thicket]

I have a 2005 115 Mercury 4 stroke EFI. I bought it this June and it ran great all season. I just winterized it. I pulled out the #1 spark plug and noticed it is really black, crusty and not normal. I noticed oil around the spark plug hole. I pulled #2 and the plug was a little better but black and not normal. #3 plug was better and #4 looked perfect. I noticed there is oil around all 4 plug holes, is this normal to have oil around plug holes on a 4 stroke? I checked the oil level all season long and it is full. I do have one other question. Every time I took the tri toon out, I would get a critical alarm and it would reduce the power. Bring back to neutral, alarm goes away and doesn't do it again until the next time I take it out. It never got hot, oil level good, etc. etc. Everything checks ok but it does this EVERY time I take it out, only once each time. Sometimes within the first 10 minutes, sometimes an hour after I take it out. Thanks.

 

[Chris1956]

Well, oil on the spark plugs is not normal on a 4 cycle motor. However, when you winterized it, did fogging oil get introduced into the motor? It is a usual thing, and that can cause what you are seeing.

 

[thicket]

No, I had not fogged it yet. But like I said, the oil level was fine. Engine doesn't smoke. Runs great.

 

[Texasmark]

You aren't getting any answers because it is a baffling question after the 1st answer. Good luck.

 

[flyingscott]

Do you do a lot of trolling with your engine.Also do you have any idea how old the plug is may just need new ones. You need to have that alarm checked out not something you want to let go

 

[WIMUSKY]

I would put in new plugs and see if you still get oil on them. Have you done a compression check? I know it runs great, but still.... I'm trying to remember if you could have good compression and still have bad oil rings...... Think of your motor as a car engine. The plugs should be a nice caramel color...

As far as the alarm, it could be a bad sensor. I would figure that out since it wants to shut your motor down. There could be an issue that could damage your motor.... When you turn the key to the on position, does each light on your dash come on one at a time, oil, temp etc?

 

[thicket]

Well, this is not my first boat, just my first with an outboard. I build engines etc. so I'm not stupid when it comes to engines. I've just heard how temperamental these outboards can be. Anyway, the bottom plug is the nice caramel color and they get worse as you go up to #1. Just thought I'd ask and see if anyone has seen this. I am going to do a compression check, spark check and test the injectors. The injectors are brand new so I doubt thats an issue. The boat only had 25 hours on it when I bought it in June. It's an 05 Landau Elite tri-toon. I agree WIMUSKY about the alarm. I believe it's probably a sensor and will get that checked next week. As far as the lights, I don't have any individual lights. Just a center guage that monitors everything. No codes are "thrown". I don't know if the plugs are original or not. Willing to bet they are. Still puzzles me how #1 is so bad and get better as you go to #4. Thanks for your time.

 

[Texasmark]

#1 is on top. Heat is on top. Heat doesn't translate to oily and wet. Heat would translate to caramel color. None of this makes sense. Everything is upside down!

 

[flyingscott]

How did you find out that motor only had 25 hrs on it and why does a 25 hr motor have new injectors.

 

[thicket]

I know it doesn't make sense. There is an hour meter in the dash. He had to put new injectors in it because someone put water in the gas tank and he ran it without knowing. Only thing I can think of thus far is the oil? Around plug holes may be residual left from when he fogged it last year, and probably didn't change the plugs either. Not sure yet, I'll get to tear into itmore next week. You can tell this boat matches the hour meter. The thing looks brand new, motor and boat. I put 42 hours on it since June. Ran great all season. I was shocked when I pulled the plugs.

 

[ondarvr]

The wrong prop can lead to carbon build up and overheating.

 

[bassman284]

You sure the PO fogged it? Generally nobody fogs a 4 stroke.

 

[flyingscott]

Wait a minute you don't need to change injectors because water in the gas and if the motor ran water you need to do a compression test. The injectors don't care what they send through. something seems fishy. JMO

 

[Silvertip]

This is not a sensor issue and it is not an injector issue. If it were a sensor issue, all of the plugs would be fouled -- not just one or two. Bad injectors do not make a plug look "oil" fouled. Oil is getting into the combustion chamber and that can only happen through the intake, via bad valve guides and/or seals, or worn or broken rings (due to an overheat). An incorrect prop is likely to result in "making oil" which is really the inability to burn all the fuel and hence it dilutes the engine oil.

 

[ondarvr]

He said the plugs were black and crusty, not wet and oil fouled, there was a small amount of oil on the outside around the plug. Lugging can create this exact scenario, doesn't mean that's what it is, only one possibility.

 

[thicket]

Sorry guys, been working a lot. The correct prop is on the boat, first thing I checked. However, there are two other props in the boat that are not correct. So, I'm willing to bet he ran these at one time. Not sure if he fogged it or not. I don't see any fogging service preformed on any of the service invoices I have dating back to 2009. Some people say to fog it, others say don't. I do not but I know many that do. Sorry I was vague on the injector issue. It was more than just water. The boat sat for 2 years with the same gas in it and was bad. He thought he'd dump a bunch of fresh gas in it and didn't know the gas can was full of water, from his kid. So, it was mainly the bad varnished gas. He had the whole fuel tank cleaned and the system cleaned out. Only one injector was bad, looking at service invoice, but per the customer, replace all four with new injectors . This was done in 2009. . The sensor issue is a whole other issue. Nothing to do with injectors or oil fouled plugs. The engine is not "making oil" either. When I changed the oil, no gas smell, it wasn't diluted and oil level was fine. The engine is definately not lugging either. I really don't think the rings are bad either. It doesn't smoke or use a drop of oil. I'm really leaning to these plugs being original or haven't been changed for a long time because the last invoice I see for plugs was in 09. I have all the service documentation for this boat. I don't see anything major other than the injector issue. I have the boat put away for the winter now. As soon as spring hit's, the first thing i'm doing is a compression check to rule that out. This engine really does run great, idles great, full throttle great. I'm really hoping i'm making something out of nothing. Just got nervous looking at the 2 plugs. Thanks guys for your help. I do appreciate it. I'll let you know what I find. Thanks.

 

[ondarvr]

You said that it's the correct prop, and that it's not lugging. What RPM's is reaching at WOT?

 

[thicket]

When I first got the boat, it would only get to 5200 RPM. I knew this wasn't right. Pulled the prop off and put the correct one on. I get right up to 6000 RPM but I run it at 5800 tops. So, I'm sure the previous owner was lugging it.

 

[ondarvr]

looks like you have it dialed in.