I have a 14′ with muzzy exhaust/ intake… my sons been driving it for the past two months with zero issues.

Yestersay mid driving it started to get a real bad sputter, only happening at full throttle, today I removed the carb and thoroughly cleaned it, replaced the plug ( which looked to be fouled ).

I replaced the plug and put everything back together, she is still sputtering at full throttle, I can hold it about 3/4 throttle and it’s fine.. the last 1/4 is where the issue is.

During the carb clean I was going to move the needle clip up one to lean it out but found it was already at the top adjustment. The jetting is 135/40 and the carb is a Keihin. I didn’t think these came stock with keihin carbs but it looks identical to the factory carbs I found online.

I also checked the small white fuel filter which was clear of debris.

Could it be a bad pump? Jetting change? But it was running fine with current jetting.. we are at sea level.

Any thoughts???

Thanks in advance

Utah RZR Rentals