There is a lot of confusion about this because the regs can come from both WDFW and the local authorities (usually the sheriff).

If it's a county rule, then you might be able to have your gas engine on the boat, but if it's a state reg, then no, you may not. In Kitsap County, it's my understanding that gas engines are prohibited, period, on lakes so posted by the county.

I didn't find this out the hard way, but after launching my gas-powered outboard on Buck Lake (didn't use it, of course, but I wanted the platform with the bow-mount electric) I did some checking afterward.

Keith