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What plug should i run?

4K views 6 replies 4 participants last post by  Pyroguy794 
#1 ·
I was wondering what plug i should run in my sled. The sled calls for a br9es plug but i have heard that the br8es is a good plug to run because it is hotter so it will foil less plugs. I know that the xlt calls for a br8es plug. my sled is a 1996 polaris ultra sp 680.
 
#2 ·
If you're having trouble with oil-fouling, then going to a hotter plug might help.

I would suggest going with a BR9EYA first or even a BR9ECS. Basically the same plug as the BR9ES except a few minor differences to help keep them from fouling.

Going with a hotter plug may plug-foul, that is, burn the plug. Basically melts the copper electrode.

Spark plugs are a fine balance between running to hot and to cold. To hot, it causes plug issue, to cold it causes oil/residue build up.

That said, 9 to 8 isn't much of a difference and probably wouldn't matter.

BR9EYA has a V grooved electrode design to lessen the fouling. This is what Arctic Cat has ran for years on their carb'ed machines.
BR9ECS has a shorter ground electrode and is at a sharper angle. This is what most modern carb'ed machines are running.
 
#3 ·
I would run what the manufacturer says to run. Bear is right, going from a 9 to an 8 may not cause problems, but it may. Why risk it?

If you are oil fouling with the 9's, something else is wrong. Too much oil, too rich a condition are likely candidates, as is bad spark due to poor contact between the wire and the plug cap. The engine should run perfect with the 9's.
 
#4 ·
Also, going to a hotter plug will only mask the issue [carbs are set too rich at some part].
The most common reason for a Poo running rich is that the chokes [enricher] are not functioning properly or are out of adjustment and remaining open when shut off.
Next would be being jetted too rich for the elevation it is being run at.
 
#5 ·
Could the chokes being stuck open be the reason why it is idling so high? im not sure if you saw my other post about it idling high. when its idling high at 4 grand or so when i put it on half choke it drops to like 1,000 to 1,500. my brother (motorcycle mechanic) also said to check out the chokes too.
 
#6 ·
A high idle that goes away with the application of the choke is most commonly a lean condition at idle. Check the carb boots and PTO crank seal for leaks by spraying carb cleaner or engine starter around the seal with the engine running. Any leak will cause a change in idle.

If there is no change, try cleaning the carbs, paying particular attention to the pilot jets. You may have varnish build up that is making the effective size of the jet smaller. Sometimes it's pretty difficult to get off, and putting in new jets will be needed. You can also try turning the air screws IN 1/8 of a turn, then re-try. Start with 1 turn out on all three carbs, and go from there. Keep going until the idle goes down, or the screws bottom. If they bottom, that really points to a problem in the pilot jet circuit; either the air/fuel passages to the pilot jet or the pilot jets.
 
#7 ·
Took out all the chokes and cleaned them up made sure they were opening and closing. After i got them back in i tried starting it and it started up so i shut it down to put it on the stand and after that it wouldnt restart and it just kept backfiring.
 
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