Kinsler_Handbook_#32 April 2024

Kinsler Fuel Injection, Inc, 1834 THUNDERBIRD TROY, MICHIGAN 48084 U.S.A. www.Kinsler.com Phone (248) 362-1145 Fax (248) 362-1032 116 Tank vent too small. Fuel level low in tank, or tank too small. Tank poorly designed; return fuel blasts bubbles down into outlet. Tank in bad location (hot, too low, or too far away). Poor quality fuel or old fuel. Hot fuel temperature or high vapor pressure gasoline (winter grade). Inlet hose to pump: kinked, clogged, too small. Angled or restrictive fittings. Loose fitting or pinhole in hose; allows pump to suck air. Separating or torn inner liner; allows flap of hose material inside to pop up when fuel flows through hose, may look OK unless carefully inspected. See FUEL PUMPS on Page #101 for minimum hose size and inside diameter for the inlet hose and fittings. Restrictive or clogged fuel filter or screen. Shut-off valve not fully open, too small, or vibrating closed. Debris under top fitting (above spool) in barrel valve. Pump too small or wrong pump-to-engine drive ratio. Drive hex so worn that it slips, or slipping drive belt. Worn or damaged fuel pump; pump hex bottomed in drive. Faulty in-pump relief valve (early Hilborn pumps only). Pump shaft seal faulty causing pump to suck air. Main bypass jet too large. Damaged or No jet sealing o-ring in main bypass or any valve that uses a jet. Dirty nozzles; check screens for dirt or lint. Nozzles too small. High speed bypass set too lean (if used) or not sealing properly. Barrel valve spool indexed incorrectly or fit too loose causing secondary to bypass at wide open throttle. Tank vent too small (see reference #1 at bottom of page). Restrictive fittings (small inside diameter) in bypass hoses or in tank. Restrictive bypass lines (kinked or clogged). Main bypass return hose teed with other bypass hoses. Main bypass jet too small. Stuck poppet in main bypass jet can Main or high speed bypass installed backward in hose. Teflon poppet , restrictive outside diameter. Nozzles too large. Nozzles not matched properly or different size nozzles. Dirty nozzles; check screens for dirt or lint. Restrictive nozzle hose (plugged, kinked, or damaged). Barrel valve not adequate for fuel rate required. TROUBLE SHOOTING CHART CONSTANT FLOW SYSTEM FOR WIDE OPEN THROTTLE REFERENCE #1- Primarily on gasoline burning engines. Gasoline generates considerable vapor pressure when it is contained in a closed tank. The return fuel blasting back into the tank creates more volume of vapor than the volume of gasoline used, so the pressure in the tank increases and causes the unit to go richer. Alcohol and nitro units go lean if the vent is too small, as they can’t draw the fuel out of the tank quick enough. See FUEL TANK CONSTRUCTION and LOCATION on Page #184 for proper vent sizes. © 2020 ENGINE RUNS LEAN ENGINE RUNS RICH POOR DISTRIBUTION Fuel Tank Plumbing Fuel Pump Metering Plumbing Fuel Tank Fuel Pump Metering