On Fri, 28 Apr 2017 16:39:54 -0700 (PDT), Garrett Fulton
wrote:

On Friday, April 28, 2017 at 11:50:29 AM UTC-4, wrote:
More 9N stuff. The gas tank has crud in it. I don't know how much but
there is enough to mostly clog the outlet. The old fuel in the tank
just dribbles out. After I get the clog removed and the tank drained
I'm thinking about using a pressure washer to clean the tank insides.
While the tank is in the tractor. I have a 90 degree fitting for my
pressure wand that would allow getting all the insides washed down.
Suggestions? Opinions?
Thanks,
Eric

Eric, I believe you're wasting your time with the pressure washer. Tried that with my '67 MF 135 and the fuel bowl/filter was plugging again in a couple months with rust. Took the tank to a radiator shop locally that soaked in a hot caustic tank, cleaned it, and sealed the inside. No worries for several years now. If the caustic treatment opens up a hole, you needed a new tank anyhow. Just my .02.

Garrett
And after cleaning in the caustic tank, any repair - whether welding,
brazing, or soldering, is very simple.
Cleaning the tank ON the tractor is a "fools errand" regardless. Pull
the tank, pour in a couple quarts of fine sharp gravel, and fill half
full of water, then shake vigorously for 15 minutes or so. drain,
empty, inspect and repeat as necessary untill the tank is clean. Then
get yourself a tank "swish" kit and coat the inside of the tank. A
Motorcycle kit will be adequate for a 9N. Just make sure whatever
product you buy is hooch resistant. Some of the old style stuff cannot
stand up long term to even E5.