Troubleshooting Propane Mowers
Contents
1. AND TROUBLESHOO PROPANE FUEI PROPANE education amp research INTRODUCTION TO PROPANE FUELED MOWERS Key Differences From a Gasoline Mower The propane fuel supply must be turned on when the mower is started and turned off when it is shut down using a manual valve on the cylinder Propane is stored as a liquid under moderate pressure 100 200 psi The propane fuel cylinder is a sealed pressure vessel that must match the type of fuel system vapor or liquid service installed on the mower Propane vapor fuel systems include an electrical lockoff a pressure regulator and a propane mixer that replaces the gasoline carburetor All components of a propane fuel system are propane specific and must be approved for use with propane Components of a Propane Vapor Fuel System Vapor Fuel Supply High Pressure Cylinder Hose Propane Mixer Carburetor Low Pressure Fuel Line Pressure Regulator Propane Conversion Disconnect the mower s electrical system Remove the gasoline tanks fuel lines air filter assembly fuel pump throttle fuel filter and carburetor Retain the gasoline tanks if they are to be used for mounting mower controls Pre assemble the propane regulator fuel line connections and mixer according to the manufacturer s instructions Install the regulator on the chassis Install the mixer and air filter assembly on the engine Mount the fuel supply cylinder securely on the chassi2. Backfiring 1 Backfiring may be caused by a mechanical problem with a valve or rocker arm Check them Backfiring may also be due to an overheated spark plug caused by an improperly adjusted air fuel mixture Check and adjust the mixture Backfiring at idle may be due to mechanical failure Backfiring under load may be caused by an overheated or worn spark plug Backfiring through the intake valve is not common It is usually caused by a failed rocker arm or push rod Backfiring during deceleration is due to an over rich fuel mixture from a clogged air filter Check the filter and service as needed BACKFIRE Propane Odor 1 If the operator smells propane there is a leak Propane smells the same as natural gas because the same odorant compound is added to both fuels Close the cylinder service valve and check for leaks Use a propane leak detector or an approved liquid leak check solution that acts like a soapy water solution If odor is present at all times check the cylinder valves and connectors for leaks If odor is present only while engine is running then the regulator diaphragm is defective Rebuild or replace the regulator If the cylinder service valve is defective have a propane supplier check the valve pump down the cylinder and replace Do not try to replace the valve due to the pressure in the cylinder typically 100 200 psi Do not try to transfer the fuel to another cylinder Your propane s
3. e regulator if possible Most air fuel mixtures are not adjustable If so equipped check the maximum gas flow control to see if it has become loose or gone out of adjustment Misfiring Misfiring is typically caused by an ignition fault Check the spark plug spark plug wire and ignition coil Check the vapor hose to the mixer carburetor for cracks If misfiring occurs at idle then check the air fuel mixture If adjustable adjust according to the manufacturer s specifications If the unit has a sealed mixture control with tamper proof screws then replace the regulator h s m rs o DAMAGED SPARK PLUG continuted on back gt
4. ect the internal valves and seats Repair or replace as necessary If the regulator is tamper proof replace the regulator assembly Loss of Power 1 Check that the engine can rev to full speed with no load Adjust throttle cable if necessary Apply a light load to see if the engine can power up to full speed If it can t check the air filter Check the maximum gas flow control on systems that are so equipped If provided adjust for proper full throttle power and emissions Engine Quits 1 2 3 An engine that quits lacks either air fuel or spark Lack of air Disassemble air filter inspect and clean Lack of fuel Check fuel lockoff The lockoff is wired in series with the chassis safety switches Check fuel filter if present Propane can pick up red rust from storage tanks that can plug a filter Lack of spark Ignition failure is typically not due to propane fuel Check the engine manufacturer s service manual Overheating 1 2 Overheating is usually not fuel related Check for lawn debris blocking cooling fins Check for damaged cooling shroud or damaged fan Use compressed air not a power wash to clean the engine approximately every 100 hours In rare cases overheating may be due to an air fuel mixture that is significantly out of adjustment Usually this condition is associated with a strong exhaust odor and poor performance Adjust the air fuel mixture and repair or replace th
5. s with the locator pin in the hole on the neck ring to ensure correct orientation Propane System Inspection Check cylinder type vapor or liquid service Vapor and liquid service cylinders are not interchangeable Inspect the cylinder for damage Check cylinder position locator pin in hole on neck ring Check cylinder mounting cylinder secured firmly in place If the straps are broken replace them Check cylinder requalification date If the month and year on the cylinder is more than 12 years earlier than the current month and year replace or requalify the cylinder DOT VAPOR SERVICE CYLINDER VAPOR WITHDRAWAL TUBE VAPOR SPACE LIQUID SPACE Pa LOCATOR PIN lf you are approved by U S DOT to re qualify cylinders follow DOT procedures and recordkeeping requirements Remove the cylinder from the mower inform the owner and record the cylinder serial number and date Inspect fuel lines for damage UV deterioration abrasion oil soaking Route lines away from sharp edges moving parts and hot surfaces Heating hoses if equipped inspect for leaks and proper routing Replace any damaged hoses or hose clamps TROUBLESHOOTING A PROPANE MOWER No Start Check for fuel in the cylinder by opening the fixed liquid level gauge Check that the fuel lockoff is energized and the ground wire is connected Check the pressure regulator for failed internal parts Remove regulator and disassemble on a bench insp
6. upplier has special equipment to evacuate a cylinder Liquid Slugging Slugging only occurs in vapor fuel systems If a mower is operated on an extreme incline liquid fuel may enter the regulator from the vapor withdrawal tube 2 Check that the fuel cylinder is a vapor service cylinder 3 Check the orientation of the fuel cylinder locator pin in neck ring locator hole 4 Ifa strong odor of propane exists the pressure regulator may be frosted This is a strong indication of liquid slugging 5 If slugging occurs shut off the mower close the cylinder service valve and allow the fuel to dissipate LIQUID SLUGGING LIQUID Vapor Service Cylinder 6 If so equipped check the hydraulic lines to the vaporizer for the correct connection 7 Ifthe fuel cylinder is the correct type and slugging persists substitute a fuel cylinder that is known to be good and re check operation For More Information Propane Safety www propanesafety com National Standards National Fire Protection Association 58 Liquefied Petroleum Gas Code 2011 ed NFPA 58 Chapters 5 and 11 cover component specifications and engine fuel applications To view or order copies visit www nfpa org State and Local Codes State and local laws may exceed or supersede NFPA standards Contact the authority having jurisdiction in your area for requirements applicable to propane or propane fueled equipment INTRODUCTION TO PROPANE FUELED MOWERS
Download Pdf Manuals
Related Search