My Yamaha Bruin will only go about 12-15 mph at high rpm?

Question edited for clarity.
Question moved from motorcycles to ATV model category.

Turning over has nothing to do with the carburetor! Your battery is flat. It will need charging.

If the carb is leaking, it is because the float is set wrong or the float valve needle isn't seating properly.

Engines only need three things to run.

A supply of clean fresh fuel (not sitting a year)
A Spark at the right time.
Compression.

You say you cleaned the carb **in** carb cleaner, as opposed to *with* carb cleaner. Did you strip it down, check the float for holes, clean the jets and needles?

Question edited for clarity. Add maker.
Question moved to Yamaha Bruin category.

Likely to be a fault with the ignition switch Karen. There is help in the link.

https://www.google.com/search?q=2004+Bruin+350+won%27t+switch+off

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Is the new carb oem part or aftermarket? Could be running too lean.

could be the starter clutch.

there should be a screw located on the bottom of the float bowl. but on some quads it might not be easy to reach without long skinny flat head screwdriver. my suggestion is to take off the carb and give it a good cleaning. water can cause deposits and lead to clogs

speedo cable prob broke.

test: plug, spark plug cap, coil then stator pickup coil.

You will need to replace the head gasket. Tightening the head will not work once the oil has found a path to leak out.

sounds like a bad seal on the crankshaft where the pull starter attaches.

Close to the battery on thr red wire in a plastic cylindrical fuse holder.