Stripped bolts, everything overtightened. what to do?

[Transmatic]

The previous owner over tightened everything he ever touched on this quad. I'm trying to remove the carb so I can go to a 42 pilot 155 main jet. But I can't get the 2 screws loose that hold the plastic throttle valve cover in place. Already sprayed them with some good stuff to help break loose. Also I can't use much pressure with the Phillips head because they are already pretty much stripped out. Any suggestions?

Also noticed I have a broken valve cover when I was removing everything. Where can I pick up a replacement?

[LxMxL97]

The previous owner over tightened everything he ever touched on this quad. I'm trying to remove the carb so I can go to a 42 pilot 155 main jet. But I can't get the 2 screws loose that hold the plastic throttle valve cover in place. Already sprayed them with some good stuff to help break loose. Also I can't use much pressure with the Phillips head because they are already pretty much stripped out. Any suggestions?

Also noticed I have a broken valve cover when I was removing everything. Where can I pick up a replacement?
Drill the head off of the screws then grab them with a pair of vice grips and for the valve cover I'm sure there's a bunch on eBay

[CJM]

Valve cover can be had on ebay. DO NOT OVER TORQUE THE VALVE COVER BOLTS! They are literally 6 ft-lbs I recall. I tighten them by hand by holding my hand on a 1/4 drive ratchet head and making them hand tight.

As for removing whats busted-hand impact driver. The kind you can get at sears would work well. Works by smacking it with a hammer and voila its off. If that dont work, drill or cut the screws with a pair of wire cutters (dikes) and buy new ones at home depot (they are metric screws and easy to find)

[81dasher81]

to get the cover off take a phillips screwdriver and a hammer, tap on the screwdriver, it usually helps break them loose.

[ride red 14]

put a little valve grinding compound on the screw head and then try your phillips head on it. the compound gives it something to bite with.

[Transmatic]

Thanks for the tips fellas. I'll get that ******* off tonight.