well i took her for a rip on the highway and the guage slowly ran down from normal, which is around a quarter to a half on the guage, to just above the zero mark. I checked the oil, full. Checked the wires and i got good power and everything to the sending unit. Im going to take it off and clean it and try it again. If anyone has any ideas they would be greatly appreciated.

 

Worn bearings. When the oil is cold you have more pressure. As the oil warms up it get thinner and you have less pressure.

Think of your oiling system as a controlled leak. As bearings wear, tolerances increase and the leakage increases resulting in less pressure.

You might try a mechanical oil pressure gauge - the stock version just gives you a rough idea of whats happening.

Fortunately, if a flathead has SOME oil pressure it'll probably do just fine if you take it easy.

You could also try additives - Lucas or STP - but there are always trade offs. Only real cure is new bearings.

 

ya i just contacted the guy i bought it from and he said that it would do that when it was hot outside. He just said to check the oil regularly