How to remove 1/4" valve/mower height knobs?

[Skyco]

Long story- a few months back the top off a jug of PowerService magically jumped 2 feet out of my hand and went in the fuel tank opening of my BX24
So months later the tractor shut off on me like out of fuel. I immediately though of that dang jug cap, must have blocked the outlet. I shook it violently via the ROPS and got it back up the driveway. When it shut down again, I pulled the fuel line where it hooks to the filter..nothing. Quick air burst into the fuel line back to the tank, blowing off whatever was blocking the exit, and fuel was again pouring out, confirming a fuel stoppage.
So after 2 hours of labor and after almost turning the BX over I got the cap into the corner of the fuel tank under the filler hole where I managed to pick it out. Problem solved- I thought.
Well today it did it again..a quick violent shake of the tractor again and I'm off and running. An inspection of the recovered Power Service cap revealed the paper gasket is missing, obviously still in the tank and that is probably what is blocking the outlet at times.

So....I was gonna remove the fuel tank and clean it out really well and look for that dang paper disk.

But- I can't get the darn 1/4" valve and mower height knobs off! They must be removed to get the plastic rear fender set off to get the fuel tank out. All this is detailed in the workshop manual except how those knobs come off! I've pulled on them so hard I was afraid I'd break something and cannot get them to budge.

Anyone know how to get them off?:licking:

 

[Skyco]

Update-
Never did get the knobs off- so instead I dug out my 12V diesel pump setup, pumped out all the fuel, took the nozzle off the output and made a restrictor so I could pressure wash the inside of the tank with diesel with a smaller hose I could wave around in there. The input line to the pump is about 3/4".
Eventually by squirting the diesel back in with the output hose waved all around in the tank and at one point just letting the suction hose sit in the tank while I squirted around in there I think I got and shredded the disk as it went through the pump. I also disconnected the fuel line and ran the garden hose in the tank for 20 minutes or so to hopefully flush out any more paper pulp.
Final pass of all the diesel through the Mr Funnel trapped a significant amount of paper "pulp" and some water from my rinsing. Hope I got it all:thumbsup:
Today I plan to check the first fuel filter for any additional water or paper pulp after using the tractor some.


Side note- should have took a pic- I had the front of the tractor elevated with the FEL on a log and the left BH stabilizer lifting the left side, so the entire tractor was on a pretty good tilt to the right and rear making the accessable corner of the fuel tank the lowest point, just under the filler neck.