Fuel Pumps
General Information Fuel Pump Description/Operation Testing Troubleshooting Fuel Pump Fuel Pump Components Fuel Pump Removal/Installation Fuel Pump Cleaning, Inspection, Disassembly and Reassembly Fuel Pump – Cleaning/Inspection Check Valve Reassembly Carburetion Fuel System Troubleshooting Checking for Restricted Fuel Flow Caused by Anti-Siphon Valves Fuel System (Carburetor) Fuel System (Linkage) Carburetor Adjustments Initial Starting Adjustment Low Speed Mixture Adjustment Carburetor Float Adjustment Specification Sheet - WME Carburetors Carburetor Fastener Torques Settings Fuel Pump Specifications Fuel Pump Pressure Sealants Idle Speed Adjustment Main (High Speed) Jet Adjustment Rejetting Carburetors For High Altitude Operation Jet Orifice Size/Part Number Chart Carburetor Removal and Disassembly Carburetor Disassembly Cleaning and Inspection Carburetor Reassembly Idle Air Screw Enrichener System Enrichener Valve Hose Installation Enrichener Valve Test Acceleration Pump Fuel Flow Circuit Fuel Tank Fuel Tank Components Fuel Line and Primer Bulb Assembly Fuel Line Clamp Removal and Installation
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Johnson - Evinrude Service Manual Application: Outboard & Sea Drive (Sea Drives) For 48 50 55 60 65 70 75 85 88 90 100 110 115 120 135 140 150 175 185 200 225 & 235 HP (Horsepower - Horse Power) Outboard & Sea Drive Marine Engine Johnson/Evinrude 2Stroke 2-Stroke Two Stroke & 4Stroke 4-Stroke Four Stroke models. The Evinrude Johnson Outboard Shop Manual: 2-40 Hp 1973-1990 is very helpful for anyone taking apart to repair an engine. It has sections of the manual dedicated to the electrical system, the fuel system, and too many sections to mention.
Fuel Pumps
General Information FUEL PUMP DESCRIPTION/OPERATION The fuel pump is a crankcase-pressure-operated, diaphragm- type pump. Crankcase pulsating pressure (created by the up-and-down movement of piston) is transferred to fuel pump by way of a passage (hole) between crankcase and fuel pump. When piston is in an upward motion, a vacuum is created in the crankcase, thus pulling in a fuel/air mixture (from carburetor) into crankcase. This vacuum also pulls in on the fuel pump diaphragm, thus the inlet check valve (in fuel pump) is opened and fuel (from fuel tank) is drawn into fuel pump. Downward motion of the piston forces the fuel/air mixture out of the crankcase into the cylinder. This motion also forces out on the fuel pump diaphragm, which, in turn, closes the inlet check valve (to keep fuel from returning to fuel tank) and opens the outlet check valve, thus forcing fuel to the carburetors. CHECKING FOR RESTRICTED FUEL FLOW CAUSED BY ANTI-SIPHON VALVES While anti-siphon valves may be helpful from a safety stand-point, they clog with debris, they may be too small, or they may have too heavy a spring. Summarizing, the pressure drop across these valves can, and often does, create operational problems and/or powerhead damage by restricting fuel to the fuel pump and carburetor(s). Some symptoms of restricted (lean) fuel flow, which could be caused by use of an anti-siphon valve, are: 0001 Loss of fuel pump pressure 0001 Loss of power 0001 High speed surging 0001 Preignition/detonation (piston dome erosion) 0001 Outboard cuts out or hesitates upon acceleration 0001 Outboard runs rough 0001 Outboard quits and cannot be restarted 0001 Outboard will not start 0001 Vapor lock Since any type of anti-siphon device must be located between the outboard fuel inlet and fuel tank outlet, a simple method of checking [if such a device (or bad fuel) is a problem source] is to operate the outboard with a separate fuel supply which is known to be good, such as a remote fuel tank. If, after using a separate fuel supply, it is found that the anti-siphon valve is the cause of the problem, there are 2 solutions to the problem; either (1) remove the anti-siphon valve or (2) replace it with a solenoidoperated fuel shutoff valve. Testing Install clear fuel hose(s) between fuel pump and carburetor( s). Run engine, and inspect fuel passing thru hose(s) for air bubbles. If air bubbles are found, see “Air Bubbles in Fuel Line,” below. If air bubbles are NOT found, see “Lack of Fuel Pump Pressure,” continued on next page. Troubleshooting Fuel Pump PROBLEM: AIR BUBBLES IN FUEL LINE Possible Cause Corrective Action Low fuel in fuel tank. Fill tank with fuel. Loose fuel line connection. Check and tighten all connections. Fuel pump fitting loose. Tighten fitting. A hole or cut in fuel line. Check condition of all fuel lines and replace any found to be bad. Fuel pump anchor screw(s) loose. Tighten all screws evenly and securely. Fuel pump gasket(s) worn out. Rebuild fuel pump. PROBLEM: LACK OF FUEL PUMP PRESSURE Possible Cause Corrective Action An anti-siphon valve. Read “Checking for Restricted Fuel Flow, Caused by Anti-Siphon Valves” preceding. Air in fuel line. “Air Bubbles in Fuel Line”, preceding. A dirty or clogged fuel filter. Clean or replace fuel filter. The fuel pickup in fuel tank clogged or dirty. Clean or replace pickup. Worn out fuel pump diaphragm. Rebuild fuel pump. Defective (hole or crack) check valve(s) in fuel pump (unlikely). Rebuild fuel pump. Broken check valve retainer. Rebuild fuel pump. Pulse hole plugged. Remove fuel pump and clean out hole.
Troubleshooting Fuel Pump
(continued) PROBLEM: LACK OF FUEL PUMP PRESSURE Possible Cause Corrective Action Hole in pulse hose (1 pulse hose). Replace pulse hose. Loose pulse hose. Tighten connection. Boost diaphragm gasket distorted or out of place. Check seal between mating surfaces where “rib” divides pulse chamber – gasket must align with rib; check for distorted gasket. Align or replace gasket if necessary. Fuel Pump Components (Design 1) NOTE: In fuel pump reassembly, remember that respective diaphragms go against the mating surfaces of the fuel pump body, and respective gaskets are between the diaphragms and end caps. Gaskets should always be replaced on fuel pump assembly. 2002 Johnson Outboard 140 Hp V4 Service Manual Pdf
a - Fuel Pump Base
b - Fuel Pump Body c - Chamber Plate d - Gasket, Base e - Fuel Filter – Inline f - Gasket, Pulse Chamber g - Diaphragm, Fuel Pump h - Retainer, Check Valve i - Check Valve j - Check Valve Rubber Disc k - Main Compression Spring End Cap l - Main Compression Spring m- Boost Diaphragm n - Boost Chamber Gasket o - Boost Compression Spring End Cap p - Boost Compression Spring q - Retainer, Check Valve r - Check Valve s - Check Valve Rubber Disc t - Check Valve Assembly
Carburetion
Fuel System Troubleshooting Troubles, that are caused by items 1-thru-5, listed below, may give the impression that a problem exists in the fuel system: 1. Spark plugs 2. Ignition spark voltage 3. Cylinder compression 4. Reed valves 5. Ignition timing Troubleshooting Charts
The Johnson-Evinrude Workshop manual downloads for the above listed models describes the service procedures for the complete vehicle. Follow the Maintenance Schedule recommendations to ensure that the outboard is in peak operating condition. Performing the scheduled maintenance is very important. It compensates for the initial wear that occurs during the life of the outboard motor.
All chapters in the Workshop Manual apply to the whole vehicle and illustrates procedures for removal/installation of components that are in detailed step-by-step fashion. Most all Workshop manual chapters start with an assembly or system illustration, diagrams, exploded parts view, pictures, service information and troubleshooting for the section. The subsequent pages give detailed procedures.
2002 Johnson Outboard 140 Hp V4 Service Manual Download
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