Sounds like you may have some wood which has absorbed some fuel. There is a product (garment spot remover) called K2R which will probably pull most/enough of the fuel residue out of the wood to allow a decent repair.

Gunsmiths use a more effective product (It is called "whiting" ) to remove oil from gunstocks, available from Brownells;
www.brownells.com, item # 083-032-100, phone 800-741-0015.

In extreme cases, I have had to remove oil soaked wood and replace with new wood.

With any finish, all cut-outs for switches, fuel fittings, pushrods, access holes or whatever, should be done before the finish is applied to avoid allowing fuel any access to unfinished, unprotected wood.

Hope this helps.