gq fuel gauge

[healy]

got a gq 3ltr carb fuel gauge not working properly. What could be the problem? It goes up 3 1/4 after 50 ks or so it drops to a quarter dont know how many k's it should roughly get any suggestions

[Airstrike]

Is it an aftermarket tank? If so has it been plumbed and set correctly

[healy]

Is it an aftermarket tank? If so has it been plumbed and set correctly

nah its all original