Is the tank empty and dry? May go boom with electric.

Huh? Maybe if you have an electric drill that shoots sparks out the motor.

OK, do whatever you want. If the motor has brushes it will spark even if you cant see it. Old 110v drills were really bad. Drill away.

i have three cordless drills and they all spark inside by the brushes.my cordless impact tools also make sparks.imo it would be dangerous to drill on or near a fuel tank containing gasoline with any electric drill.

I understand what you guys are saying completely. The potential is there. But how do the Sparks get into the gas tank? It's pretty much sealed up and the only thing that is going to be exposed to the tank is the drill bit.

On a side note I just looked at my cordless stuff and they all have spark arrestors. Not sure if they are USGC approved or not.

Well, fumes could be present. You could hook up an old bilge blower to your fuel fill to evacuate fumes. I have heard of too many gas tank repairs gone wrong...just one thing overlooked and you may not like the results.

BB, I think the big concern is not sparks falling into the tank, but the gas vapors that may possibly be ignited. I have tried to limit that by stuffing paper towels into the bung holes (Beavis says "HaHa, he said bunghole!" :D ). Nonetheless, I have an air drill that I will probably use IF I need to drill this thing out oversize. I would like to do what Hadley did with his, and just run a hand tap in the existing 3/8 NPT threads and keep it that size. I think eliminating the restriction from that 90* fitting and the little bitty barb fitting will go a long way towards giving me some volume.

Thanks for all the replies, guys. Some useful info on this thread for future OSOers!

JR, I agree - I am extra paranoid about gas fumes. I don't heal up as fast as I used to!

I tell you what, when I use my Makita corded drill in the mist, I get shocked like you would read about.

My Craftsman, you can see the sparks flying around it, inside the vents.

Lastly, it's the vapor you have to worry about.

Wanna know how many GM trucks from the eighties and 90's has burn to the crisp wiring in the fuel sender/pump harness inside the tank and never blew up ? Has to be because was not in fuel vapor/oxygen combo.

You guys really crack me up.