SEAL-O-RING 4K4879 - Caterpillar

All Caterpillar Diesel Engines Features/Benefits
* Obtain a more accurate reading of fuel flow rates* Slowly closing the needle valve until air bubbles are no longer visible in the fuel flowmeter sightglass will result in a more accurate reading Measuring Fuel Flow Accurately
When using the Caterpillar Fuel Flow Monitor System, 1U-5430, 1U-5540, and 1U-5450, it may be difficult to accurately measure the return fuel flow because of air bubbles in the fuel. This will cause the turbine flowmeter to read higher fuel flow rates than actual.
It is recommended that a needle valve (B) be installed at the outlet of the flowmeter (A) reading return fuel flow. See the illustration.
Start with the needle valve fully open. By slowly closing the valve until air bubbles are not visible in the fuel flowmeter sightglasses, a more accurate reading of the return fuel flow can be obtained.
Parts needed for 4C-9759 Return Flowmeter Group (small)
* Needle Valve - (Parker Hannifin Part No. N800S)* No. 8 JIC female fitting - (Weatherhead Part No. 9100X8X8)* No. 8 JIC male fitting - (Caterpillar Part No. 3R-5387) Parts needed for 4C-9761 Return Flowmeter Group (large)#
* Needle Valve - (Parker Hannifin Part No. N1600)* No. 16 JIC female fitting - (Weatherhead Part No. 9100X16X16)* No. 16 JIC male fitting - (Caterpillar Part No. 094440)
Components in a typical fuel system(A) Caterpillar Return Fuel Flowmeter Group(B) Needle Valve(C) Primary Fuel Filter(D) Caterpillar Supply Fuel Flowmeter Group(E) Fuel Transfer Pump(F) Fuel Filter(G) Fuel Supply Line(H) Fuel Injection Pump(J) Fuel Return Line(K) Diesel Fuel TankFor further information call the Caterpillar Service Technology Group Hotline: 1-800-541-6665 inside Illinois; 1-800-542-8665 outside Illinois; Canada 1-800-523-8665; World 309-675-6277.
Reference
SEHS8874-01; Tool Operating Manual, Using the Caterpillar Fuel Flow Monitor System