I gassed up my 2004 Sundancer 240 the other day and the gas gauge stayed at 1/4 tank and then later dropped to empty. From what little research I have done so for, it appears that I may have a bad gas level sending unit. I looked in the engine compartment and it appears that the fresh water tank will need to come out to gain access to the top of the gas tank to replace the sending unit. Any helpful advise will be greatly appreciated. Should try to identify the sending unit part number , order one, and have it on-hand prior to starting the repair so I will not have to wait for the part to finish the job? Am I mistaken and the gas tank will need to be removed as well? Thank you.