2004 Polaris 700 Carb-Misfire

[trollingforeyes]

This happens at cold start in the winter only since new. Sounds like it is firing on one cyclinder untill mostly warmed up. I have pulled the plugs and the one on the RH side is carboned up more the the left side. I have replaced both plugs to no avail. Does someone have the specs for checking the coils with an ohm meter? Iam thinking that I may have a weak coil.

[WingDing2]

I am going to ask a really stupid question, Do you clean the carbs every year? I dont think its your coil.

[trollingforeyes]

No carb cleaning. Carb was modified after 1 yr by the Polaris dealer ( warranty for cold start). Same misfire before and after mod. Gas is mixed with seafoam when not used for any period of time. ATV has 700 miles on it. When warmed up it runs perfect, which makes me want to look at coils.

[leech~~]

troll, is it miss-firing or back-firing? If it runs good once warmed up you may have some kind of rich choke problem when cold and warming up?

[trollingforeyes]

It is misfiring. If I take off the choke it still does it till it leans out and starts to stall. Why would it show more carbon build up on 1 cylinder and not the other. This is a single carb feeding 2 cylinders.

[leech~~]

well you make some good points on the single carb, and only one side carboned up! Maybe weak coil or maybe a bad valve or rings on that side head? But just to clarify, is it stumbling (mis-fire) or Popping loudly (back-firing)

[Dave S]

leech~~ is on to something. There's few things it could be:

1) rings or scored cylinder wall

2) valves

3) coil

4) plug wire

I know some people have switched over to a Dynojet in their carb and it's improved the performance of the machine. But I have my doubts that will fix your problem.

You might want to check the compression and make sure that's good. Also check to see what shape your oil is in. Does it smell like gas?

Has the machine ever stalled while submerged in water? What type of riding do you do?

[trollingforeyes]

Machine has never been submerged, water maybe up 1/3 up the tire max. Riding is adult style. Only 700 miles on machine. Oil -good, no gas,clean. It is not poping ect. Just not firing on the one side. I have verified by feeling the exhaust pipe next to cylinder at start up cold(10 degrees and colder). One side cold other getting hot.

Originally thinking coil, looking for parameters to check with ohm meter.

[leech~~]

trolling, I would do a compression check! I can see rings or valves seating better when things warmer up, but not sure why your coil would work any different when it warms up? A lot of manuals talk about bring it back to the dealer to readjust the valves after so many miles when new. I have never done this on anything I have ever had and don't know anybody that has. But it's in a manual for a reason and maybe yours in one out a hundred that needs the valves readjusted after break in?? But what the heck, if it runs Ok after it warms up! Let it warm up and run it!

[Whoaru99]

Machine has never been submerged, water maybe up 1/3 up the tire max. Riding is adult style. Only 700 miles on machine. Oil -good, no gas,clean. It is not poping ect. Just not firing on the one side. I have verified by feeling the exhaust pipe next to cylinder at start up cold(10 degrees and colder). One side cold other getting hot.

Originally thinking coil, looking for parameters to check with ohm meter.

WIthout having the primary and secondary parameters you could at least compare the readings of the two coils.

Something else you might try is to take a plug and make the gap extra wide. Try it on both sides (just make sure to have the plugs well-grounded to the engine) and see if they have similar spark appearance.

[SSCHOPSHOP]

My 700 was that way to, I put a jet kit in it and run HIGH OCTANE FUEL. Problem gone, I think the fuel is the biggest part. I now run 91 or 92 in all of my small engines. It just don't go dead as fast as the low octane fuel does. I myself don't like Sea foam I use Stay Bull. (spelled something like that lol)

[trollingforeyes]

The dealer put the jet kit in when new. It helped the cold starting below zero. The misfire was the same before and after.