Need some help with firing issue on scrambler 90!!!

Bought this bike after it had been sitting several years in storage. Put some fresh fuel in it and cleaned the carb good. Carb was in pretty rough shape. It fired up and ran good for a couple hours. My nephew got it in a mud puddle but it was still ru Ning good until the ride home it cut out. It was pretty rich on oil because I mixed the fuel in the tank also as a precaution incase the factory oiler was not working so I figured it was the plug fouled. I replaced the plug and it fired up and ran a few minutes good and did the same thing again. At this point I figure it was the carb flooding because when I pulled the plug you could see wet fuel on the plug. So I cleaned the carb again and still same thing. Problem seemed to get even worse. I replaced the carb with a new one which didn't make much difference. The bike is to the point it will fire up and idle for a few minutes but with any throttle or load it will bog and die and then won't start again.
I replaced the plug again thinking maybe it fouled again. Still same thing. I at this point bypassed the factory oiler and just using the premixed fuel in the tank. I finally pulled the new plug and cleaned it and checked fire by leaving the plug attached to the coil wire and holding it to metal on the bike and kick it over. It had a few weak looking Sparks and then nothing. So I figured the mud puddle probably killed the stator. I opened it up and the stator looked pretty dirty muddy etc. I ordered a new stator and coil and replCed both today and it still did the same thing. It fired right up but with much throttle at all it would bog and try to die and then finally dies and would not restart. I pulled the plug and checked fire again and it had none.
The only thing I can think left would be the ignition box. Is there a way to bypass the key switch and kill switch on the handle bars to eliminate those as being the issue before I spend another $100 plus on an ignition box? If the puddle killed the stator would it have killed the ignition also?

first check compression. always start there even though it ran. the Polaris kill switches are known to act up. put the quad on a stand and pull the kickstart cover and run it to see if the belt if traveling up and down on the front variator and rear pulley. while it's apart you should install a new rear torque spring. also, check your fuel mix. we ran ours at 40:1 with amsoil synthetic premix and 100 octane but just make sure you use a quality premix. you could have the mix off and it's running way too rich. if you're letting it idle and it's rich you're gonna foul plugs and give you the hard time starting.

Compression is good. The issue is with firing

hmmmm it might sound odd but it happened to us. the plug boot went bad . I bought a new ngk replacement and cut the coil wire back a little to expose new material and threaded new boot in and cured no spark problem just a suggestion also, what type of plug are you using ?? make sure the wires feeding the coil are tight and you have good grounds

Running Ngk BPR7HS plug. I also just installed a new fox coil at the same time as the stator was installed.
It doesn't have a hard time starting it will fire up first or second kick and run or idle for a few minutes and then stops firing. Whiles it's running it has weak fire can't give it much throttle or put a load on the engine or it tries to die. When you pull the plug out after it does and won't start it will have a little wet fuel on the plug and no fire. I even swapped a brand new plug on to check for fire and still nothing.

you said you cleaned the carb ?? is it a sunworld carb ? did you make sure the pilot jet was perfectly clean ? all the little holes need to be clear. I know you're chasing a spark problem but to not be able to touch the throttle like that are signs of a fat carb or pilot jet problem. how about the A/F screw. it should be 1 1/2 turns out. are you using the factory airbox ? try pulling it off and see if it runs any different. I see you tried a different carb with no results but where did the second one come from and was it clean/good ?? you got rid of the oil injection which is good and now you can go to a single pull throttle cable to make it easier to ride

clean all the ground wires that connect to the frame!...the exhaust pipe is probaly clogged as well..good luck

gotta agree with turbojoe. pull the pipe and see if anything made a nest in there. happened to my kdx200