Adding a Fuel Bowl Riser
For many years I have had a problem with moisture in the fuel on my AC Model B tractor. It was caused by condensation in the fuel tank. In the springtime and throughout the summer when I normally use the tractor, it would cough and die after a while and I would notice water in the fuel bowl. I was continually having to clean the fuel bowl of such water droplets to keep the tractor going. AC never installed a low point drain in the tank and the gasoline pick-up for the fuel bowl is at the bottom of the tank. Any gunk or moisture that settles to the bottom of the tank gets directed to the fuel bowl assembly. The screen in the fuel bowl generally handles the gunk and rust particles but small water droplets can get through and are ultimately fed to the engine, killing it. The situation can get so bad that the engine dies, can be restarted OK and runs for a while but dies again until the bowl is cleaned. That lasts for a while but the entire process repeats itself.
My Oliver 77 diesel fuel tank has a special low point drain and the inlet to the fuel bowl is raised up off the bottom of the tank. Before I painted my AC-B fuel tank, I decided to apply the same principle and modify the installation to suit.
I had a couple of weep holes due to rusting at the bottom of the tank so I was going to braze them up anyway prior to painting. I would add a dedicated low point drain to the tank at the same time. Here is what the new drain looks like:
I brazed in a 1/4" brass pipe coupling and attached a radiator drain petcock. The fuel bowl attaches to the threaded-hole boss on the left. CAUTION: If you are going to braze on a fuel storage tank, make sure you take the necessary safety precautions. It can be a very hazardous procedure otherwise. After brazing I also coated the interior of the tank with a two part epoxy sealer from Caswell
I added a riser to the fuel bowl assembly in order to get the inlet above the bottom of the tank. This provides a low pocket area for sediment and moisture to collect without getting into the fuel bowl. This area can be drained periodically using the new drain petcock. I used a short piece of 1/4" OD brake line that adds about an inch in height. It presses into the existing fuel bowl adapter coupling nicely. Here's what it looks like:
And here's the final installation on the tractor:
This was done three years ago and has solved my moisture-in-the-gas problems forever more. I use the new petcock once per year in the springtime to drain off any collected moisture. I wish I had done this years ago.