Hook up a tube to all the drains, and flush it.
Might just get the crud keeping the float open to flush through and out the drain.
If you have a friend with a garage, you probably could do it yourself, but I thought so too, and it worked ok for me, but I should have sent them to Steve anyway, since he had them a week or so later because I was having other issues.
Ill say this, for those wanting to do the overflows themselves, AFTER I did mine, I found a MUCH better solution (it seems) than the JB Weld everyone was using, and better than the stuff I used (KBS coating) which seems ok, but not sure how long it will last.
Loc-Tite 660 Press Fit repair. From their literature:
LOCTITE® 660 is designed for the bonding of cylindrical fitting
parts, particularly where bond gaps can approach 0.50 mm
(0.02 in.).
From what I found, their testing resulted in no degradation of strength from inital to 1000hrs in:
Motor Oil
Unleaded Gasoline
Brake Fluid
Water/Glycol 50/50
Ethanol
Acetone
Thats fairly impressive, and should I ever have an issue, Ill be using that to reinstall the tubes. I dont feel real comfortable long term with my solution, but it will probably be fine.
FWIW, if you use a drill press, the correct size bit, and the correct size tube, it will be a very close fit anyway, but hand drilling can make matter much worse than this stuff can fix.