Maybe look into R/C Model paints?
There are other brands of same technology sealant - The degreaser and zinc etching is optional - that smallest size can of sealer is the magic...
Remember modern gasoline is a cocktail of refinery left-overs: Naphthas, benzene, toluene, xylene, alcohols, ethers, butane, and pentanes, any one of which might poison an otherwise good resin. The effort to re-do the project and chance of carburetor damage would lead me back to the expensive stuff.