Watch now to learn about safely using your equipment. Note: These videos are intended as a general guide for maintenance tasks. Specific procedures may vary depending on model. Always consult your operator's manual for detailed directions and safety information before attempting to perform any maintenance on your machine. This is a current model and under manufacturer's OEM warranty.
Please see warranty statement and contact your dealer before repairing. Skip to main content. Rental Sales. View All Equipment. View Used Equipment. Owner Information. Warranties Extended Service Plans. No: Check for worn, stuck, or broken piston rings, or worn cylinder bore.
No: Go to next step Engine Runs Erratically 1. Is fuel delivery correct? Does engine rpm drop or engine stall at a certain point when throttle is gradually opened by hand? Yes: Check for obstruction or plugged passage in carburetor.
Yes: Clean, adjust or replace relief valve. Is oil pump operating correctly? No: Replace oil pump. Is there fuel in the oil? Check that all starting conditions are met? No: Make sure all starting conditions are met. Is oil pump screen clogged or pick up tube cracked? Yes: Clean screen and repair or replace pick up tube. Yes: Check for broken or seized piston rings or worn cylinder. Check for worn or seized exhaust valve.
Is there water in the crankcase? Yes: Check to make sure that crankcase breather is working correctly. Are battery cables loose or dirty? Yes: Clean and Tighten. If starting motor does not stop rotating by turning ignition switch to Off position, disconnect negative - lead from battery as soon as possible. No: Charge battery. Is there a click sound from the starter solenoid? No: Repair starter motor. Is engine seized? Yes: See Engine Repair section. No: Go to next step 5. Check to see if the problem is governor or carburetor: Hold the throttle plate closed to force engine to idle.
Does the engine continues to run? If the engine stalls - suspect idle circuit. No: If engine stalls, check idle circuit. Clean carburetor with attention to idle circuit passages. Check float bowl for dirt or corrosion. Check for dirt between needle valve and seat.
Is dirt or debris present? Is the needle valve stuck closed? Yes: Check for old or gummy fuel. Clean carburetor. Check valve tip. Check air passage and pilot jet for debris or varnish. Is there debris in the idle air bleed or pilot jet? No: Adjust choke cable. See choke cable and throttle cable adjustment. Check passages in carburetor. Are passages open and free of debris or varnish? No: Clean carburetor. The majority of fuel system problems are related to stale or improper fuel or dirt.
This section is to help you diagnose fuel system problems. Initial Checklist. No: Check fuel cap if vented cap is used. Check vent lines to carburetor for kinks, or collapsed or weak areas. Verify the quality of the engines mechanical and electrical systems. Attempt to manually control the throttle at low and high idle to determine which system is causing the surge. If the engine speed can be held constant check the governor system.
If the engine surge cannot be controlled manually, check the fuel system. Properly cleaning the carburetor will likely fix the problem. Short-Tripping A common misdiagnosis comes from short-tripping machines engines that are started for short periods of time. Short-tripping causes the engine to develop black, sooty spark plugs and contamination in the oil.
Over time, short-tripping can lead to glazed cylinder walls. To prevent this, every time the engine is started, allow the engine to reach operating temperature and load the machine. Air Filters Note: Late model carburetors are internally vented to meet emissions standards. Engines with externally vented carburetors with a dirty air filter will exhibit rich running conditions.
When a dirty air filter restricts air flow to the carburetor, the low pressure in the venturi drops even further, resulting in a higher pressure differential between the fuel bowl and the venturi. Note: Verify the ignition system. A rich running condition can have the same symptoms as an improperly operating ignition system.
Engines with internally vented carburetors will not exhibit rich running conditions with a dirty air filter. When a dirty air filter restricts air flow to the throat of the carburetor, an equal reduction will be applied to the bowl vent.
With an externally vented carburetor, a rich or lean run condition could also be caused by the location of the float bowl vent tube. The purpose of the vent tube is to allow atmospheric pressure into and out of the float bowl. Air from the cooling fan at the vent tube opening can cause a pressure increase or decrease on the fuel in the float bowl and cause the engine to run rich or lean.
Check for bulletins and relocate the float bowl vent tube to a location away from any source of turbulence. Float Valve with Worn Tip Shown Fuel level in the float bowl is regulated by the float and the float valve. A worn float valve tip provides too much fuel and will cause a rich condition. Improper or Stale Fuel Poor fuel quality can cause an engine to appear to be running rich. Extreme corrosion may involve salt water. Sometimes the exterior of the carburetor will also be corroded.
The location of the machine such as coastal regions will provide additional clues to the cause of corrosion. Red or brown corrosion is usually caused by an iron or steel part that has corroded.
Look at steel fuel inlet fittings, steel parts in fuel filters. It could also indicate some other contaminant in the fuel. Some microbial contaminations can be reddish. Brown varnish and gum deposits are generally from old degraded fuel. Look for it in areas that would be adversely affected, such as fuel and air passages, needles and seats.
White corrosion or green corrosion is usually caused by water. Water can combine with other chemicals and create acids and salts which accelerate corrosion.
Water can be absorbed by ethanol, so the more ethanol, the worse the problem. Damage from excessive ethanol, methanol, MTBE, ethers, will usually be seen as damage to rubber parts.
Look for cracks, swelling, shrinking, loss of elasticity, takes a permanent set or becomes hard or brittle. Look for plastic damaged parts. Debris stuck in small orifices and other critical areas. Look in jets, fuel and air passages, fuel inlet needle and seat, idle mixture adjustment needles and seats, idle progression holes, fuel shutoff solenoid plunger, etc.
Look for the following: a. Cellulose and other organic fibers are usually grass debris that was ingested by the engine air intake or fuel system, they could also be fibers from the fuel filter element.
Sand can come from ingesting dirt by the engine air intake system or fuel system or from unclean manufacturing and parts packaging. Metallic particles such as aluminum, brass, and iron chips typically come from the manufacturing process and unclean parts packaging and assembly areas. Do not use drill or hard wire to clean carburetor passage ways. Clean debris off the outside of the carburetor before disassembly. Completely disassemble the carburetor per the instructions in the Technical Manual and visually inspect.
Plastic particles usually come from manufacturing processes such as plastic molding, welding, adhesive epoxy used in fuel filters , and unclean part packaging and assembly areas. Determine if carburetor is repairable, excessive corrosion may determine this is not practical.
Rubber particles usually come from the fuel lines, fuel pump diaphragms, or internal parts, and unclean part packaging and assembly areas. Wires and metal instruments should not be used.
Light damage or deposits on the surface of the float valve seat can be removed using a cotton swab with a mild abrasive such as toothpaste or grit lapping compound. Cardboard particles and fibers usually come from parts packaging and unclean assembly areas. Hair fibers usually come from unclean parts packaging and assembly areas. Wrong parts, such as wrong size jet or left and right jets switched.
Damaged parts, such as jets having tool marks that affect the fuel flow, cracked plastic parts, etc. Defective parts such as porosity in castings, excessive flash on castings or molded parts, defective welds or adhesive joints, throttle shafts that fit too tight or too loose, throttle plates out of alignment or not matched to bores, etc.
Carburetor Assembly When the carburetor is ready for assembly, lay out all the necessary components on a clean surface. Be aware that even clean shop rags may contain dirt and metal shavings.
Assemble the carburetor in accordance with the instructions in the Technical Manual. Many times the contamination is located in an area of the carburetor that is not visible. In most cases proper cleaning can resolve these issues. Carburetors and carburetor components can be cleaned by using one of several types of commercial cleaning methods: aerosol sprays, caustic dip tanks, and ultrasonic cleaners.
Note: Some cleaning chemicals may be flammable and have toxic fumes. Always wear personal protection gear such as safety glasses. Be sure to install the insulator using the correct orientation. This will prevent debris lodging in difficult to clean areas.
Cleaning Methods Ultrasonic Cleaning Systems Ultrasonic cleaners use environmentally friendly cleaning solution and sound waves to penetrate deep into carburetor passages. Heating the solution is an option on ultrasonic cleaners that significantly increases the effectiveness of the system.
Ultrasonic cleaner systems work by creating sound wave pulses that are transmitted through a cleaning solution. Manufactures of ultrasonic cleaners claim the pulses create small bubbles that loosen and pulverizes contaminates.
Select a chemical solution that is designed specifically for carburetor cleaning. Generally, chemicals will need to be diluted with water prior to use. When choosing a chemical, consider dilution rates to help determine which chemical is the most cost effective. Consider disposal of cleaning solution before ordering chemicals.
Check with local authorities on recommended disposal methods before disposing of any cleaning solution. Ultrasonic cleaners come in many sizes. Most 1. If an Ultrasonic Cleaner is used, place carburetor in and run for 30 minutes at F in the proper solution mix. If the solution is too strong or the carburetor is left in the cleaner for too long, the aluminum body will have a residue on the surface from the aluminum oxidizing.
Caustic Dip Tanks Caustic dip tanks use aggressive chemicals to dissolve carbon based contamination. This method is effective for most carburetor cleaning needs. Rotating the parts in the tank will ensure the cleaning solution flushes out any air pockets left in the passages. Follow the recommendation on the cleaner for submersion times. Disadvantages of the caustic dip tanks are that some carburetor parts may be damaged if left in solution too long. Personal safety and chemical disposal are additional concerns.
Because the chemical is caustic, exposure may cause injury or death. Disposal of used solution can be difficult because most cleaners are considered hazardous waste. Rinse the parts in water and dry with compressed air up to 30 psi. Aerosol Cleaner Personal safety, environmental concerns and cleaning effectiveness make this method the least desirable.
This method can be used on carburetor components that may be damaged by caustic cleaners rubber seals or other. Do not use fuel or additives containing methanol as engine damage can occur. All fuel today is formulated for the automotive industry. Newer carburetors on current production machines have less. Fuel Storage Since it is difficult to know what type of fuel is in different areas; it is best to handle and maintain fuel as outlined below: 1.
This creates deposits on engine valves and in carburetor jets and passages. This is what causes most of the performance problems.
Oxygenated or blended fuels can deteriorate faster and require more specific storage and usage procedures. The translucent fuel tanks on some model tractors allow a certain amount of sunlight through the tank. This can accelerate the deterioration of the fuel. Check Procedure: 1. Park machine safely. Remove air filter cover and air filter. Do not take internally. Avoid contact with eyes. Avoid breathing the chemical vapors. Read safety instructions on stabilizer container label before using.
Fuel stabilizer contains 2,6-di-tert-butylphenol and aliphatic petroleum distillate In case of emergency, contact a physician immediately and call for material safety information. Fill tanks with fresh, stabilized fuel. Use fuel from a major name brand supplier. At the same time, add an appropriate amount of Fuel Stabilizer such as TY Do this when you add fresh fuel to your tank. Remove the two flanged shoulder bolts B and two nuts A that hold the air cleaner base to the carburetor.
If engine performance problems arise, try another brand of fuel. You may have to try several different sources. If there is doubt about how long the fuel may be stored, add stabilizer right away.
Just imagine how much you can save by doing simple repairs yourself. Many people buy this manual just to have it around for when the inevitable happens. Sooner or later, maintenance will need to be performed. Be prepared for it when it happens by simply purchasing this service manual for later use! See below for a list of items that most of our manuals cover. Some manuals actually cover more items that are not even listed!
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