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Discussion Starter · #1 ·
07 ski doo summit 800R
800 miles on SHR rebuilt motor. Top to bottom
Nothing loose no air leaks. Runs awesome
Plug on left is pto side
Every time I've checked plugs in the past they
Have always both looked the same. Looked just like the pto
Side pictured. What's goin on here? Any help would be great
 

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Considering the picture should probably be rotated 90 degrees to the right, if both plugs normally look like the pto (bottom or left side). then the mag side is burning leaner and able to burn the carbon deposits more effectively than the pto side. Most my plugs run like your PTO from fear or running too hot, but the mag side looks better. \

The question is why do they look different? Did one of the jets get clogged during mid-season....,if we can call it that......
 

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Were those pulled out after idling? Or a wot plug chop?

If sled was idling, putting around yard, warming up in trailer etc. the plug reads are worthless....

If it was a wot plug chop I'd drop jet size and check oil pump setting
 

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Discussion Starter · #6 ·
Plugs were pulld after riding for 30 min pretty hard. Compression is dead even 140 on both sides. Have not pulled apart carbs to check for plugged jets. But it seems to run like it has all season. I have my oil pump set at 16 mm
 

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Not sure if it applies here but I remember with my old 670 the mag side would run leaner if I didn't have the jet size larger on that cylinder.
 

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The bottom one seems a little dark... but if it runs fine, its most likely from oil and not excessive fuel. What kind of oil do you run?

Drop in some new plugs and run a little sea foam in your next couple tanks of fuel.
 
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