Brandon's 818R Build

[J R Jones]

The float rheostat has a full and empty position that is communicated to the gauge.
The task is to make it agree with your actual fuel levels.
The original float travel is greater than your 818 tank, so to reduce travel to match the new tank the float rod must have a shorter swing. (shorter radius)

With the rheostat at full down, bend the float rod so the float is on the bottom of the tank.
With the rheostat at full up, bend the float rod so that the float is at the top of the tank.
A compromise may be required.
jim