96 XP Running on one cylinder, carb swap fixed it?

[zachu812]

Been chasing my tail all summer with my 96 XP where it has been running only on the mag cylinder, I ruled everything else out and finally swapped on the carbs from my 97 XP and now it runs on both. Now I'm trying to figure out what could be wrong with my original carbs? Everything I did is listed below, what could I be missing?

• Used genuine Mikuni gaskets, diaphragms, needles, seats, and pop off springs
• Set pop off at 40psi and verified it doesn't leak down
• Made sure diaphragm doesn't hold needle open
• Verified that fuel pump is sending fuel to PTO carb
• Cleaned all jets and passages with a wire strand and flushed with brake clean
• New fuel lines
• Synchronized throttle blades
• Set both needles to spec

I'm pretty stumped here, what else could I be missing that would cause the ski to only run on the mag carb? I know for sure it's a carb issue after swapping on the carbs from my 97 but I'm lost now.

 

[zachu812]

Finally figured it out today. Bought a good used set of carbs and as I was going through my old ones to steal parts from I noticed that metal plate in the center of the diaphragm was just a little bent. Even though it tested ok with the cover on it still wouldn’t run on the engine. Just something to look out for.

 

[etemplet]

Did you put the other carbs back on the ski to verify this was the problem? I would have checked the feed line from the MAG carb to the PTO carb. I don't see how that would cause a dead cylinder but... never know. LOL Glad your ski is running. They can be quite sneaky.

 

[zachu812]

Did you put the other carbs back on the ski to verify this was the problem? I would have checked the feed line from the MAG carb to the PTO carb. I don't see how that would cause a dead cylinder but... never know. LOL Glad your ski is running. They can be quite sneaky.

Yea I didn't install the used set after I found this, put the "problem carbs" back on with just a different diaphragm and it was firing on both. I did check the feed line from mag to pto carb previously, was pumping strong. Took both out last night and everything ran great.

 

[etemplet]

Perhaps the deformation was causing it to flood the carb with fuel. Glad you go it going.