I don't think water in the fuel could have caused the damage that resulted in a fire. but a backfire could. a weak ignition coil , a bad plug wire maybe had crossed fire with another wire and caused a backfire . what ever caused the problem should be dealt with before you attempt to start the engine back up.

you will need to rebuild the carb, or get a replacement, do not run it as it is!

you used water to put out the fire right? you can remove the distributor cap , plugs and let the engine air-out overnight , most of the water should be gone, next check to make sure the water didn't crack the distributor cap, since you said the engine was running before the fire. electricity and water don't mix to well without something getting a little damage. there is a dielectric lube in a rattle can you can get from most auto-parts stores and you can spray under the distributor cap, to make sure the heat of the fire and water don't rust anything, but only spay a very small shot of it or you will need to wipe the excess off with a rag.

its a little tricky rebuilding a holley carb if its your first time so I would suggest either get someone that knows how or get a new carb.

you had 2 fires now so I'm sure you are wide awake by know and are very cautious, go the extra mile and check all wire's, hoses, and fittings for any leeks that can cause another fire.

I have seen what could have been some nice rides sitting in the bone yards that were victims of fire. don't let your ride die that way.