i am using the in tank fuel pump and level sender from the s2000 donor. its mounted on top of tank and is 4 a wire arrangement.
1;feed to fuel pump
2;fuel pump ground
3;level sender feed
4;level sender ground
so how does the level sender work (tell the dash how much is in the tank) with only a feed and a ground?

Float attached to an arm. Also attached to the arm is a contact that the arm moves across a reostat (variable resistor in effect). When the tank is full float is at the top and the contact at the low resistance end. Tank empty and the opposite. Lower the resistance the more current flow (to earth) and the higher the reading at the gauge and visa-versa.

I'll let someone else do "How does a gauge work?"

thanks again. so the honda level sender will work without the standard honda clocks?

It wil work as it is a variable resistor, however, it depends on which gauge you use as if they are not compatable the gauge will be inaccurate. Barry

The gauges range is dependant on the resistance range of the sender unit so another gauge will work but might not be accurate.

you can correct the difference with some resistors, but it will be a bit hit and miss, the gauges wont read accurately over the full range.