Literally every nut bolt and screw will have to be removed to replace tank
Tank is part of the crankcase so unless you want to have the crankshaft in your hand, leave it alone.
Try fixing chip with JB WELD or a similar product.
Most folks would patch it and call it good, but that's asking for leaks and fires. Truth is, if you can't fix it right, you probably shouldn't be running that saw
