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Discussion Starter #1
k my buddy has a mach z 780, punched out to a 820 i think he said. The 3rd cylinder, closest to the clutches is fouling and we cant figure out why, it has brand new plugs in it, when u check there is tons of spark, there is tons of gas cause the plugs are wet when u pull them out after pulling it over. And when u run it for awhile the pipe outta that cylinder is ice cold, but yet the other 2 pipes are steaming hot. Anyone know what could be causing this to happen?? thanks
 

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If the pipe is cold, you have no/weak spark. Most likely you have a coil problem and have weak spark. Try switching the coil around and see if the problem follows the coil. Did you do a compression test on all 3 cylinders? That is always a good place to start. If neither of those helps any, you are looking at a stator or wiring issue. Try the compression test 1st. If that is good switch the coils around. If those do not work, let us know.
 

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Discussion Starter #3
k thanx ill be over there tommorow and we will try that, i wanted to do a compression test but he didnt have a tester so im gonna take mine over
 

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COULD BE WAY MAJOR!!! has he shredded a belt? I did on a 98' MXZ and a piece of belt wrapped around the shaft and took out the Crank seal!! Not friggin cool, 700 bucks to have it dealer repaired. Anyway, check that seal.
 

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yep start it up and spray some starting fluid around that seal and see if it picks it back up (bet it does)
 

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Originally posted by powder_special_900
[br]k my buddy has a mach z 780, punched out to a 820 i think he said. The 3rd cylinder, closest to the clutches is fouling and we cant figure out why, it has brand new plugs in it, when u check there is tons of spark, there is tons of gas cause the plugs are wet when u pull them out after pulling it over. And when u run it for awhile the pipe outta that cylinder is ice cold, but yet the other 2 pipes are steaming hot. Anyone know what could be causing this to happen?? thanks
 

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check the ground wire on that coil. it should be white wire. they are only held together with a small metal tab, i have had them break off and unless u remove the coil you would think everything is ok. also check the plug caps u would be amazed how much a bad $2.79 part could end up costing you.
 

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I would think that if it's the crank seal, the sled wouldn't start or run very long as the motor wouldn't be able to pull enough vacuum to pump fuel to the carbs. He's getting gas. just not enough spark to the one cylinder. do as stated above, and check compression and spark.
 

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Discussion Starter #9
well we finally got it running for anyone who is interested. Compresion was 115-120 lbs on each cylinder, had tons of spark, plugs were getting wet. So we put all brand new plugs in, gapped them proper, and now it runs..... not sure what we did, if it was just the plug or what.
 

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sweet sounds like a fun sled glad to hear shes running again
 

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Discussion Starter #11
haha well this weekend he shredded a belt, so were gonna pull the clutch off to see if he tore at that crank seal.... good thing i posted this or else i wouldnt of know it could do that.
 
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