While trying to start the car it loudly backfires out the left side tailpipe

Car been sitting for 5 months up here in rainy Seattle I last ran the car last summer ran fine. Today I went to start it first the engine bay was moist from condensation I took a blow dryer and dried the distributor then cap turned it over and it did not start I shot some starting fluid into the carbs and tried again it backfired loudly out the left tail pipe. I looked at the firing order that seems right 153624 took out spark plugs turned it over to clean out the cyl. Turned it over with no backfire but it did not start sprayed starting fluid into carbs backfired!. Are the floats stuck you think?