2000 Yamaha bear tracker 250

[Lbs]

Ok customer brought me a 2000 Yamaha 250 idles great and will run wide open but when you take off from a idle it tries to die and sometimes will die said took it to a mechanic he put a different carburetor on same thing took to another mechanic swapped carburetor again same thing so he brought it to me i went through all 3 carburetors cleaning, adjusting same problem i checked compression only had 90psi so i put new rings, piston, and jug on now have 155psi with same problem any ideas?z

[Ajmboy]

So it bogs down when you hit the throttle off idle, correct? Is the choke working properly? Typically I would guess there is not enough fuel flow or fuel in the carb bowl so when you hit the throttle it goes dry but maybe you have a spark delivery issue. 

[Lbs]

The plug was replaced before I replaced the rings but i pulled it out this morning and it is pretty black so i gonna replace it and see what happens but i also forgot to mention he said previous mechanic replaced everything to do with spark also before i got it was out of time but i did time it back correctly when i tore it down

[alexwv1863]

I've had a similar issue with a 2006 Arctic Cat 400. I had a mechanic tell me it'll happen when there's a loose magnet on the flywheel. Im still working on it, but it's something you could check into and see.