Yamaha, T50TLRA, 2002

by Steve Swaisland
(Bradford, Ontario, Canada)

The engine is new to me and ran well the first dozen times out. Now the engine runs rough. I believe it is cylinder 3-as I changed the plugs and this plug color is different. Previous was able to achieve 5000rpm now Max is 4500. I ran a high concentrate of sea foam through the engine and a large amount of black came out shortly after reving the engine in my driveway. Took back to lake and still have same issue. The engine will run but just rough. The plug wires appear good but not sure how old.

My feeling is that the carb is having issues, think not coil or wires since the coil runs cylinder 2-& 3 and only cylinder 3 plug looks bad.
I am handy but never pulled apart a set of 4 carbs, I have disassembled and cleaned many single carbs but nothing like this.

Any thoughts of things I can try before I take to the shop.

The plug on the left is from cylinder 3 the other from 2.

Any help is appreciated.

Thanks Steve

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