Welcome to the forum Derek
Remove tank and clean !
Do a Google search for "How to clean old fuel tanks".
Many ways to do it, just pick which works best for you.
Might want to check carbs also, might be same crap in float bowls.
Would guess after ya get it running some or most of your fuel line will be leaking ...
Two cycle motors DO NOT like bad fuel, plugged carbs, water and crap in fuel !
Fuel tanks under your splash well are fine, but YES .. Make sure your battery is in a plastic box, so there no chance of spark from something contacting terminals.
Trace where wires are going from " round mechanism " ...
Interior light dimmer ?