OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames New member mower questions for restoration

You can get a basic outline of draw-filing here:
http://armyordnance.tpub.com/Od16218/Od162180135.htm

The subject of draw-filing Briggs fuel tank tops comes up in these threads:

https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=22526#Post22526

https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=46083#Post46083

You might also have a look at this ebay item:
http://www.ebay.com.au/itm/OEM-Brig..._Power_Equipment&hash=item3397d5be6f

Unlike some of the sellers, at least he knows there are supposed to be washers in the kit, and he states that some are actually still present in what he is selling. Again unlike some of the sellers, his postage charge seems reasonable.