#2 exaust temp. guage running hotter than 1 and 3 cyl.

[TreeTop]

First things first,,,,, im a 1st time sled rider and purchased a 1996 Polaris Ultra 680 triple and a 1999 Ski-Doo Formula Z 500. I've been crusing the Polaris around for a couple of days on some trails and this sled has a temp guage for each of the 3 exaust pipes, and the #2 pipe is running way hotter then the #1 and #3 pipes, any reason for this or any idea on where to start. I was hoping it was just the guage being a bit off, but like I said I'm a rookie to this and would like to find out why this pipe temp so hot. Any help would be very appreciated.

 

[danduvall]

is the spark plug on the #2 cyl whiter (leaner) than the other 2? what are your actual exhaust temps? how do all 3 plugs look? (cardboard brown is ideal). it sounds to me like you have a lean condition on your center cyl, could be caused by a leaky carb boot, mal-adjusted carb, etc

 

[brushfit]

I have read somewhere on here that the center cyl needs to be jetted richer because it does run warmer...I just picked up a pol triple for a parts sled but haven't really looked at it much...starts right up.

 

[X2Freeride]

Need to run 2 sizes larger jets on the middle cylinder. It runs hotter than the other two.

 

[danduvall]

you should check your plugs often and jet accordingly. no matter wich cyl is running rich or lean. you should jet each cyl so they all burn the same no matter what! and once you have your jetting set (considering you dont make any intake exh or temp changes) ... and one or more cyl continues to falls out of tune. then you have other problems!!

 

[TreeTop]

is the spark plug on the #2 cyl whiter (leaner) than the other 2? what are your actual exhaust temps? how do all 3 plugs look? (cardboard brown is ideal). it sounds to me like you have a lean condition on your center cyl, could be caused by a leaky carb boot, mal-adjusted carb, etc

Temps on #1 and #3 are around 600-700 cruzing around about 30 mph (not sure of the rpm, i'll check next time i go out), but the #2 is at 900-1000.

Checked all the plugs, PTO side is cardboard as the #3 side is also, the #2 cylinder is a little darker than #'s 1 and 3. cleaned the carbs 2 days ago, noticed the #1 jet is 390, #2 is 370, #3 is 380, why is this, should I change the #2 jet to 390 or 380? or is there a reason for these all being different? please let me know. Thanks.

 

[X2Freeride]

The middle jet definately shouldnt be the lean jet in the mix.

 

[DanB]

Temps on #1 and #3 are around 600-700 cruzing around about 30 mph (not sure of the rpm, i'll check next time i go out), but the #2 is at 900-1000.

Checked all the plugs, PTO side is cardboard as the #3 side is also, the #2 cylinder is a little darker than #'s 1 and 3. cleaned the carbs 2 days ago, noticed the #1 jet is 390, #2 is 370, #3 is 380, why is this, should I change the #2 jet to 390 or 380? or is there a reason for these all being different? please let me know. Thanks.

Several things:

1) You said you are cruising around 30 MPH, so you aren't running on the main but rather you are running on the needle. Look at the needle clip position on all three carbs. Some would run their Ultra's with staggered needle clip positions. Regardless, since you are not taking these temp readings at WFO (and thus running on the main) then changing the main is not worthwhile at this point.

2) The center plug is darker which would indicate a rich condition and not a leaner one, so this makes the temp reading suspect. See #3 below.

3) It sounds like you have the Westach gauges (or the Westach triple gauge). In order to eliminate the gauge or the probe, swap the probes between the center cylinder pipe and one of the other pipes and see if the increased temp remains on the center cylinder or if it follows the probe.

Let us know what you find.

 

[TreeTop]

The exhaust temp guages are SLP, i'm getting out tomorrow, so i'll switch the probes and see what happens. and i'll get a rpm reading while riding also.