BASIC TROUBLESHOOTING
OF GRASSHOPPER LAWN MOWERS
AND ENGINES ON GRASSHOPPER LAWNMOWERS

SPECIAL NOTE TO THE READER:


While the following is somewhat basic, the writer has intentionally left out various things which one would expect the reader to know about before attempting to apply what is written. Basic understanding of electricity is a must and safety concerns must be considered before attempting to troubleshoot any mechanical or electrical system. If you do not feel you have this knowledge or training you should consult a properly trained service technician.

ENGINE WILL NOT START-

First you must determine if the basic elements for starting your engine exist. You must have air flow through the engine, fuel getting to the top of the cyliner, and ignition spark at the spark plugs. If any one of these three elements do not exist or are restricted in some fashion then you will not have the required conditions for engine starting.

The following is not necessarily in a set order, read all the possible causes before attempting to determine what the problem is. It is up to you to determine what will be the "easiest" to check for first.

ENGINE STARTS
BUT THEN DIES WHEN KEY SWITCH IS RELEASED TO RUN POSITION-

A COUPLE OF THINGS CAN CAUSE THIS.

LIGHT FUSE BLOWN?
If the light fuse is blown, this symptom will show up.

DIODE BAD ON CIRCUIT BOARD.
Diode between upsidedown "L" and second pad from top on left side of board.
DIODE PART NUMBER 202100

NO SPARK BASICS-


Are the ignition coils producing spark?
Look for cracks in the spark plug "ceramic insulators".
A very fine crack can allow for the spark to jump through the crack to ground.
Is the air gap for the spark plug properly set AND CLEAN?
Is the connection between the spark plug wire and the spark plug a good connection?
Is the ignition coil producing a good spark?
Be careful with testing an ignition coil for spark, you could feel the power of the ignition coil if you are not careful! Also be careful of any fuel spills that may become ignited when working with the spark plug wires and testing for spark.

IGNITION COIL AIR GAP-

Is the ignition coil air gap properly set?
Some engines work better on the high side of the air gap specification.

Is the small wire going to the ignition coils being pinched and grounding the spark?

Are the spark plug electrodes wet with fuel or water?
Either will prevent a spark. Remove the spark plugs and check, turn the engine over to ventalate the cylinders before putting the spark plugs back in place. Be cautious of loose spark plug wires producing stray sparks and fuel pumping out of the cylinders. A fire could be caused by not paying attention to these elements.

SAFETY SWITCHES NOT FUNCTIONING PROPERLY-

Is the spark being produced grounded? A switch or safety device may be bad. A bad switch could be causing the spark to be grounded to the machine frame when it should not be. Are the mechanical parts pushing on the safety switches when they are supposed to. Case in point-
We found once on a Silver Eagle, the hinges on the seat base plate to be "bent". This caused the base plate to be twisted in its relative position to how it hits the switch found under the base plate. This base plate had holes in the plate near where the switch was "pushed on" and because the base plate hinges were bent, the holes in the base plate permitted the push pin on the switch to fall into one of the holes causing the switch keep the engine from starting. Not all Silver Eagles have these holes in the base plate.

NO SPARK DUE TO SLOW ROTATION-

Is the engine being turned to proper "minimum" RPM to generate a spark?
A weak battery causing the starter motor to turn slower than necessary could be your cause. Don't be fooled by an engine that rotates, but does not produce spark. This slow rotation could be slow enough to not produce enough Flywheel magnet induction when it passes the ignition coil (armature). Some engine specifications requie 250 RPM for proper "minimum" rotation to produce a spark. Ask, do I have Bad or weak Battery, does the battery need to be charged, is the starter weak?

An electric starter that is turning, even though it is turning the engine over, it can be a weak starter turning the engine slower than required. It only takes about 30 to 40 minutes and a new starter to find out. Don't test the old starter, put on a new one and be done with it. The time it takes to put on a new starter is less than testing one and your bench test might not be able to reveal "Torque" that the starter produces. The true test is to install a new starter.
Try a new fully charged battery first. It is cheaper than trying a new starter. If you can't start it the next day, did your battery go dead, causing the engine to rotate slower than it should?
Keep in mind also,
High compression can cause an engine to be "tight"
and not turn fast enough to produce spark. Normally this is only on new engines that the valves have not "grown". If your engine has 600 hours on it then your valves are probably not the problem, but still could be contributing.

NO SPARK DUE TO WEAK FLYWHEEL MAGNETS-

The flywheel magnets can be weak.
The only way to really test this is to put on a new flywheel. Putting a screwdriver blade on the flywheel magnet will show you that you do have magnatisim, but how strong is it? Keep this in mind when all else fails, you may have a weak flywheel magnet. For the same reason of slow rotation, if your magnet is weak, your ignition coils will not produce enough spark to start the engine.

NO FUEL

Are you out of fuel?
Don't be fooled by a small amount of fuel in your tank.
Low fuel levels in tanks can cause an engine to not start.
Some fuel tanks have fuel pickup tubes that don't go all the way to the bottom of the tank.
PUT FUEL IN THE TANK!

WATER IN THE TANK-
What is in the bottom of your tank ?
Water is heavier than the Gasoline
and will settle to the bottom of the tank.
Your fuel pump could be pulling water from the bottom of your tank.

Is the fuel tank clogged inside at the bottom outlet ?
Plastic shavings from manufacturing the fuel tanks could collect
in the area of the fuel outlet fitting and restrict the flow of fuel.

Is fuel coming out of the fuel tank?
Is the fuel outlet on the tank clogged?
Is the fuel valve open?

Is the fuel filter clogged or full of water?
Is the fuel pump working?
If your engine has a fuel pump, is it pumping fuel?
Is your fuel pump an electrical fuel pump or Vacuum operated fuel pump?
Is fuel coming out of the fuel pump during rotation?
Is fuel coming out of the fuel pump?
Is fuel getting to the fuel pump? An external fuel filter could be blocking fuel flow. Check the filter element to see if it is saturated with trash causing the obstruction. If any doubt, replace the element.

If you do not have a good external fuel filter you may have a clog inside the fuel pump.

Is the fuel solenoid valve opening?
Look on the bottom of the carburetor, your engine might have a magnetic controlled valve that opens by magnetisim. If battery power is not available to the valve coil then the valve will not open. Electricity could be present and coil could be bad or stuck. Is the valve stuck closed?
Is the main jet on the carburetor clogged? The main jet in the carburetor can be clogged. The jet is removable from the carburetor assembly. You may just want to replace it with a new jet.
Is some sort of external fuel shutoff valve closed? A valve between the fuel tank and the engine may exist. Someone may have closed it for some reason. If you find this to be the case, you should find out why they closed it, there might be a problem.
Are you simply out of fuel? After all this, did you check to see that you have fuel in the tank? Good luck.

NO AIR FLOW THROUGH THE ENGINE COMBUSTION CHAMBER-


Are the intake valves opening?
Are the exhaust valves opening?
If air does not flow through the cylinders, fuel can not be carried to the top of the pistons for ignition. Check the valves. You might find one stuck closed because of the rocker arm coming apart or a push rod not pushing on the rocker arm to open the valve. Did the push rod fall out of place? Is it bent?

BLADES WON'T ENGAGE

Several things can cause the blades not to engage.
DID THE DECK DRIVE BELT COME OFF ?

BLADES WON'T ENGAGE MORE INFO HERE
BLADE ENGAGEMENT SWITCH IS BAD.
CLUTCH IS BAD.
FUSE IS BLOWN OR CORRODED.
ELECTRICAL CONNECTION IS LOOSE OR CORRODED.
BATTERY VOLTAGE IS LOW.

SITE MAP
CONTACT US
HOME


This web site has been made available to you for the enhancement of the services we provide to our customers. We've provided a number of resources here to help you resolve problems, find parts you need, and suggest improvements to our service.



Copyright 2009
AAAA Generator and Pressure Washer, Inc.
DBA: ARKANSAS OUTDOOR POWER EQUIPMENT
All rights reserved.
Last modified: NOVEMBER 12, 2009

All products mentioned are registered trademarks or trademarks of their respective companies.