Spark plugs half brown/white and half black

WestCoast · Apr 21, 2014

I've been having an issue with my 2012 RMK (Standard). When I first bought it, it was having an issue fouling plugs. I thought that this was because I am a new sledder and not pinning it like I should. Compression good, 120 PSI each side. I had the TPS reset at the dealer and this seemed to help some. It would still carbon/fuel foul until I cleaned my exhaust valves. Much better now. Although the other day, went out and never hit WOT due to terrible light. Poked around in the trees and came home. Started it up and wouldn't idle (it was around 1400 like previous) pulled plugs and all black. Replaced plugs, went out for a full day in deep heavy spring pow, WOT a lot. Slow on the way out due to heavy whoops for 4 miles. Came home and checked both plugs, half black on the intake side, half white/silver/brown on exhaust side. Any ideas as to the cause of this?
Also, low on coolant, about an inch from the line. It was really warm and I hit 180* on the thermostat. Is this normal to loose some coolant on a warm day like this?
Thanks for the help!
Ty

05900 · Apr 22, 2014

Have hit 180* on occasion but never lost coolant , did you or was it low to begin with?
Is it missing,running rough? Correct plugs/heat range? ........?

beamslayer · Apr 22, 2014

Plugs should be checked after a quick shut down if you let it idle you will not get a accurate plug reading .

WestCoast · Apr 22, 2014

I think that it did loose a bit of coolant. At what temp will it start puking? I had noticed that I was about 1/4" low for a time, then I ran it and it went right back to normal until this last time. It also was rolled to unstuck a few times in deep spring pow. No real cooling issues
I'm using the speck plugs for a 2012. I'm just wondering what could be causing them to foul? It seems to be at slow speeds and excessive idle. I try not to do that.
Forgive me for the silly, vague questions. I'm new to sledding and a bit paranoid. I just want to know what's normal, and what to do if it's not.
Thanks everyone for your help so far!

diamonddave · Apr 22, 2014

That's okay...that's how we all learn.

I'm a little confused. Are you fouling plugs to the point of having to change them to get the sled running again?

Or is the sled not fouling plugs anymore and they are just a black color that you are concerned with?

What is your oil usage? Have you been tracking how much oil you use per fuel used?

As for the low idle....The most common cause of this is a misadjusted throttle cable (too much slack). I like to adjust them so that there's 1/16" max slack (actaully more like 0.035" - 0.045") between the flipper and throttle housing.

WestCoast · Apr 22, 2014

It runs great until it fouls a plug and I have to change them out to get it running normal again. I have only had a no start situation twice, none since the TPS reflash. Now the problem is just real rough running and poor idle. Last time it would start but only idle around 1400 real rough with sluggish response. The sled runs great with new plugs and will be good for a few rides as long as I open it up a bit. The last time I had problems was a short trip at low speeds. Came home early due to downed trees on the road, never hitting WOT. Fired it up the next day to go back out and it would idle like caca. Pulled plugs and they were carbon fouled. Replaced plugs and runs strong. Pulled plugs after one trip on the new plugs, running WOT and noticed two tone color. Not a propper plug chop but I'm hoping for some answers.
Just concerned about the two toned color on each of the plugs after one trip. I don't know much, but I do know that I should not be fouling all if these plugs.

gman086 · Apr 22, 2014

Coolant fill line is "inaccurate". I always lost coolant if I filled to the line. Should be perfect where it's at - just make sure you're not losing any more coolant on subsequent rides! No worries.

As for the plug fouling, they changed plugs in 2012 and then changed back again recently because those plugs are horrible for fouling. Use NGK BPR-9ES that were stock on the '11's gapped slightly tighter (0.025" which is still in the acceptable range).

Have FUN!

G MAN

WestCoast · Apr 22, 2014

Right now it's idle is fine and running good. Also the coolant level has magically returned to the cold fill line!

WestCoast · Apr 22, 2014

I will give the other plugs a whirl

WestCoast · Apr 22, 2014

Well, looks like those are the plugs I'm using already...

Cooksend · Apr 23, 2014

Also remember that Piston Wash is the best way to check for a lean / rich condition. With today's fuels (additives and cleaners) it is difficult to use plug color to tune or check for lean or rich conditions!

WestCoast · Apr 23, 2014

What should I look for in piston wash? Pull plugs and look into cylinders? What's a rich condition look like? Lean?

olymon · Apr 23, 2014

Never had a polaris run quite right using ngk plugs. Always ran champions in them.

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markoo · Apr 23, 2014

Your plugs are fouled from unburnt oil. Your cylinders have to get to a certain temperature to burn all the oil. If your sled is really rich on fuel the cylinder temps will be low and oil won't burn all the way. Since its fuel injected it probably isn't too rich. So only thing it could be is way too much oil. Have you checked oil consumption? what ration are you at? Do you add extra oil to the gas? If oil and fuel are both right you just have to pin it more often.

beamslayer · Apr 23, 2014

It is really hard to see piston wash on the pros . The best way is to buy a bore scope I picked one up on Ebay for $100 . Works good for checking piston and cylinder ware and finding stuff under the engine also.

800poodragon · Apr 23, 2014

What does the outside of the plugs look like when you pull the cap off when you change them? Mine would get black from the caps going bad. I replaced them 2 different times. Would start fouling plugs pretty often and would change them..they would work ok for a bit then do the same thing till I replaced the caps....that would take care of it for awhile but then it would happen again. Keep going thru plugs till I replaced the caps. Sometimes 1 or 2 sets a day. I finally put some good MSD caps and wires on and have not had a problem. Dielectric grease helps keep it from happening as well. Just another idea to look at.

WestCoast · Apr 23, 2014

When you say outside of the plug, are you referring to the ceramic insulator that the cap plugs into, or the area with the threads? The threads and the whole bottom area are black sometimes.

OuraySledder · Apr 24, 2014

He is talking about the metal top on the plug that goes into the plug wire. They build up some carbon and either di-electric grease or regular cleaning is a good idea to have full spark.

What about reeds? Wouldn't a broken reed petal cause fouling and bad idle?

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