You have to get ALL the fuel out first, "PERIOD"
Two of us used a outboard engine hoist to lift and wiggle it out. Try a come-a-long hooked to the tanks mounting brackets. The bottom was crusted in places with small pin hole leaks. The floor had rotted out under as water reached it from the original battery boxes below. At the time of removal, I did have the large engine splashwell. I added a new tank floor before inserting the new tank.
BTW: I don't think anyone on this forum has removed their tank without using choice words of wisdom coupled with the consumption of some sort of alcoholic beverage
