Re: Searay 180 Instruments
mark, I ran the engine to operating temperature and noted the sender resistance was 107 and the temp gauge read 190. Then I removed the sender, attached an ohm meter and dipped it in a pot of water. The water temp was raised and every 3 degrees, the ohms were recorded. At 107 ohms, the water was 160F. With the sender disconnected, and a trimmer resister connected, 125 ohms equalled 160 on the gauge. So the difference is 18 ohms. I have permanently mounted an 18 ohm resister between the sender and the gauge. All is well with the temp, but the fuel gauge bugs me. The tank holds 80L of fuel. With 20L of fuel in the tank, the sender reads 195 ohms and the guage reads E should be 1/4). At 40L, 135ohms and 1/4 full( should be 1/2), at 60L, 80ohms and 5/8 full(should be 3/4). With the sender disconnected and a trimmer resister installed, E =236 ohms, 1/4full=150ohms, 1/2=100 ohms, 3/4=60ohms. My point is, the sender is not calibrated to the tank. The tank has an irregular shape, but my searay dealer won't replace it. As an ex Searay shop forman, would you expect the sender to be replaced??.