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Discussion Starter · #1 ·
I've got a 78 ski-doo everest 444 L/C and it's going through spark plugs like crazy. I throw in a spark plug and I'm lucky if I can get a days use out of it before it craps out. Does not matter what brand plug I use, I've tried bosch and ngk. What happens is the plug will start to mis-fire then eventually it will crap out all together. Visually, the plug looks fine when I take it out, just wet, but when I test for spark, it won't spark at all. Put a new plug in and I'm good to go, for a while anyway. Always seems to do it on the cylinder on the clutch side of the engine. I can't figure it out. The plug on the recoil side is always fine. I've done new wires and plugs, cleaned the carb, the plug cap on the side that always dies out tests out to around 1420 ohms, the other cap tests out to around 1580 ohms. I don't really know what else to look for. I did a compression test on it once it was warmed up a lil, both cylinders checked out to 120-125psi. I just can't figure it out!? Why is the plug on the one side just not lasting? I'm going to check point gap and timing but I don't really think that's the problem cause it runs so good once I throw a new plug in.
 

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Maybe to much timing,Could try higher octane to help if its always messing up when your trying to start it.The reason its that side is the clutch makes that side run cooler ,maybe try smaller jet on that side & check plug after wide open run & shut it off while still WFO then check plugs to make shur they are not white from being to lean
 

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Check and see if your choke plunger isn't stuck in one of the carbs, and,,is the Fuel screw turned OUT too much and/or the air screw turned IN too much? Is the needle/seat on the one carb leaking? snap
 

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444,I may be wrong,but I'd bet you have water in your tank. I've had problems too because of all the rain. Water will kill plugs. Get some Drygas( isopropyl). Use a half bottle to a full tank.It can't hurt.

Mark
 

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ok check to see where your fuel pump pulse line goes if it goes to the cyl you are having trouble with the diafram is bad and leaking gas into that cyl making it way to rich just rebuild the fuel pump and it be good
 

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Discussion Starter · #7 ·
Thanks for the fuel pump tip, I'll check that out tonite. I'll also dump in the isoprophyl see if that helps. It's only a single carb, no choke so I don't think the carb is the problem since the other side runs mint. I've tried running it on 91 instead of 87 octane, made no difference but I'm going to check out the ignition timing tonight to see where it's at. Any more suggestions are very welcome, keep em comming.
 

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Discussion Starter · #9 ·
how could you not have a choke?

what style carb is on it[/b]
mikuni carb, stock primer - no choke. What's not to understand? Ski Doo sleds came like that for a long time.

Well fuel pump goes to the other cylinder, so that idea is out.
 

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Discussion Starter · #11 ·
Well I cleaned out the carb a month or two ago and haven't really ridden anywhere since, it's single carb so that makes it nice and easy. I reset the point gaps, both were way out of spec, don't know if that'll make a difference though. The side that was giving me trouble had too much gap which also results in retarded ignition timing for that cylinder. The other side had too little gap, so I dunno. I added some isoprophyl to the gas, don't know if that will do anything. Seems to be running great in the garage now but I'll have to take it out tomorrow to see what it does.
 

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I think more gap makes it more advanced,atleast thats the way my old cats are.this would explain the problem.I bet it will run just fine now,if there set right which can be touchy & take a few trys.Haveing the points set good to get the timing on makes all the differance in point ignition sleds.
 

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Discussion Starter · #14 ·
thanks for being a total prick about a legit question[/b]
how's that being a prick? You asked what kind of carb I had that didn't have a choke, and I told you, stock mikuni carb, factory primer, no choke, standard equipment for a ski-doo at the time. When you get your head out of your ass and give it a shake let me know what kind of a response you were gunning for.
 

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I started working on sleds a long time ago,here is my best guess. If the gap was wrong on the points it would bother all the time,it's been a while but 14thousands sounds right .They should be open when the piston is at top dead center in that cyl. I think you probably have a condenser breaking down when its hot. I would put all new points and condensers in and i bet your problem goes away. While you are woking on the sled I would also pull the carb and pressure test the needle and seat. It should hold 5 ibs.I really don't believe that is the problem,if it was both plugs would be wet. :beerchug:
 

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I would not put new points in as they are all made over seas now & are'nt as good as OEM.The condenser wouldn't hurt tho_One off the reasons its more sentive now is possible 10%ethenal or differant oil.
 

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Discussion Starter · #17 ·
Well after I regapped the points and added the isoprophyl to the gas my problems have disappeared. Point gaps were way out, set them back to spec(.35mm) according to my manual. Put 40 miles of ditch banging on it today and the ol sled ran perfect. :ylsuper:
 
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