I don't know man, I've done tried my luck at that rebuild stuff and speaking from that experience it seems to me it's usually cheaper to replace the carburetor itself... Most of the time I can find them so cheap it's almost cheaper than the kits and by the time I'm figuring one hour's labor it's past over...
Careful, I did some research and I am ASSUMING I have the right carburetor here...
You'll need to double-check my work before you order to make sure:
http://www.ebay.com/itm/New-Carbure...707-799866-790845-799871-794304-/172412262068
I have no affiliation with that listing, you can order it from anywhere once you have the right numbers but watch the price + shipping.
Also that should be a US-based seller, make sure to check your estimated delivery dates.
I mean for ten dollars replace it whole, gasket(s) and o-ring(s) and all.
Can't go but so wrong there, if it doesn't work your problem's either elsewhere or you can return it for a refund.
Question 1, the seat is non replaceable, just replace the viton tipped needle.
Question 2, no gaskets, the O-rings provide the seal.
Question 3, I just use Teflon tape on all oil types of oil drain connections.
Yeah...
I don't even fool with them stupid kits anymore.