Cylinder Not Firing [Archive] - Snowmobile World : Your #1 Snowmobile Forum

: Cylinder Not Firing


joeformula3
01-23-2005, 04:38 PM
I have a 1996 Ski Doo Formula III 600, when at an idle only two cylinders are working, I am holding my hand over the mufflers to tell. I changed spark plugs (all new) and still only 2 firing, when I rev it up then the 3rd one kicks in.

I rode most of the day yesterday and thought this was happening, when going slower it would seem to jump or speed up a little like the 3rd cylinder was trying to kick in, when I get on it or hold it open I believe all three are working, like when I rev it up at a stand still.

Can anyone help me out as to what might be the problem and how I can fix it?

Thanks!!!

Good2Go
01-23-2005, 07:48 PM
when its running pull each sparkplug cap off one at a time, if the motor idles down or dies when u pull that plug wire then that cylinder is working. if u pull a wire and the engine rpm dosnt change that is the bad cylinder...

joeformula3
01-24-2005, 08:47 AM
I am pretty positive it is only running on two cylinders unless I am getting on it or holding it open, are three cylinders meant to only run on two unless your getting on them? Or do I have a bad Stator or something?

01adrenaline800
01-24-2005, 08:59 AM
suposed to run on all 3 u do have a prob. i dont know anything about triples. like he said look for the bad cylinder and check for spark.?

kragar
01-24-2005, 09:17 AM
Sounds like a fuel delivery problem. At low idle the 1 cyl may not be getting fuel to ignite and once you demand more fuel(open throtle) it fires.
Try this.....switch 2 carbs around and see if the other cyl starts to act this way and if it does...then you know its carbs. Also check fuel line to that carb for a leak.

joeformula3
01-24-2005, 10:37 AM
After a ton of reading and the replies to this post I think I will try the following.

1. Switch two of the spark plug wires around (the bad cylinder and a good cylinder) and see what happens. If the current non firing cylinder starts to fire and the current good cylinder stops then maybe its the coil or a bad cap.

If not

2. Replace wires to original position, now I will check the choke cable.

3. swap two of the carbs and see what happens, maybe a gas leak or plugged line on the currently non firing cylinder.

I will update once I have tried the above.

Any other suggestions?

Thanks

01adrenaline800
01-24-2005, 12:52 PM
dont switch the wires it wont work they all fire at different times you will solve nothing by doing this
1st pull the wire and find the bad one, when you find it check to see if you are getting spark by putting a spare plug on the wire and seeing if it sparks, if it doesnt you know where to start looking if it does then start looking at your fuel delivery to see how that is.

joeformula3
01-24-2005, 01:15 PM
Originally posted by 01adrenaline800@Jan 24 2005, 01:14 PM
dont switch the wires* it wont work they all fire at different times you will solve nothing by doing this
1st pull the wire and find the bad one, when you find it check to see if you are getting spark by putting a spare plug on the wire and seeing if it sparks, if it doesnt you know where to start looking if it does then start looking at your fuel delivery to see how that is.
393122


Thought I read in one of the post that triples fire at 120 degrees, meaning is doesn't matter what wire goes to what plug? To be on the safe side and not screw myself up I will use the method you're suggesting, easy enough.


Does anyone know if a bad coil or cdi box would produce the results I have explained up top (first post). Seems like if they were bad they would not work at all? I guess the more I think about it the more I think it may be a fuel delivery problem as suggested above? Guess i need to stop worrying about it untill I get home and can take a look at it.

Thanks!!!

joeformula3
01-24-2005, 08:00 PM
Okay I have an update, I really need help now. :bash:

I checked spark on the non firing cylinder by putting a new plug in the wire and leaving the old one in while it was running, great spark. I then replaced the spark plug in the machine with the new one that was just sparking. Started the sled and still no fire on this cylinder, unless I took the sled out a ran it hard, then the cylinder kicked in, but only till back at an idle. I then pulled the wire off this plug while at idle, no difference in idle, tried the other two that where firing and witnessed a certain diff. in idle. I conlcuded the spark is there and no problems with electircal.

Second I switched carbs with on of the working cylinders (belt side cylinder is the one not firing, middle and chaincase side are working) the one I swapped it with was the middle cylinder, guess what...no change the middle cylinder still fired fine and no fire on the belt side cylinder. I am at a loss for things that could be wrong, can anyone help?? :bash:

I should also note that the when I raised the belt cover there was oily sludge on the bottom suface, inner (motor side) off the cover. Could this have anything to do with the cylider not firing? Maybe a bad crank seal or something??? There was also a light residue of gas on the floor beneath the none firing cylinder muffler outlet.

Any help or suggestions at this point would be GREATLY appreciated!!!!

Sorry for the long post just wanted to be sure I included all facts for you guys.

deucecoupen
12-20-2005, 12:22 PM
I had this same problem and everyone thought I was crazy,but it would seem to run good
but all of the sudden it would just poor on power, very frustrating, it turned out to be an internal carburator problem,you can switch carburator positions but remember that center carb is jetted different on that sled,I did this and it fallowed that cylynder,tried everything to that carb finally tried a carb a buddy had laying around and never had problem again.

MikeD
12-20-2005, 03:03 PM
I'd do a compression test next ... if you don't have a gauge, get someone to put thier thumb over the spark plug hole as you pull the sled over. I think you'll find that the pto side (belt side) is low. Shine a light down through the spark plug hole, what do you see?

01MachZ
12-20-2005, 03:14 PM
I had the same problem with the mag side on my old 95 mach Z, It was the crank seal. Compression was good and so was spark. But with the bad crank seal it will not draw enough of the fuel/air mixture into the cylinder.

summitrevman
12-20-2005, 05:17 PM
Hope you have this fixed by now, but if not I would check the coils. A friend of mine fought this same problem for an entire season when the sled was new before they finally replaced the coil and everything was great.