Toro LX426 Issue

ego_id

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I have a 5 year old Toro LX426 that has been a great mower until recently. On Saturday I was mowing the yard and it started to make loud popping sounds (almost like firecrackers) and then I started to lose compression. I changed the spark plug, oil, oil filter, fuel filter, and air filter, but it didn't help. The engine is cranking and I am getting sparks, but it isn't turning over. Any ideas before I have to take it to a service center and spend money I really don't have?
 

Rivets

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Let me repeat a post from another thread that might just get you the help you need. Please follow it.


Since this is a help forum, it is only fair that the people trying to answer questions have some information to work with, so they can give an accurate answer. This helps them if they need to research parts or service information on your engine or equipment. In the first part of your post please include your engine numbers from the ID tag or stamping and the equipment type and model numbers that are on it. Failure to do this may result in you not receiving any accurate help with your problem.

Many of the tech's that hang out here work in or have there own shops and the first thing they do when they make up a work order on a unit is include the engine and equipment numbers on the work order. Since this technical forum is offered free to the public, it's the least we can ask you to do, so please help all of us out. *So please post the numbers in the new topic you start to ask your question. It should be the first thing you write before beginning your question. :D

Got some ideas as to the problem, but until I. Know what engine you have I don't want to guess.
 
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I have a 5 year old Toro LX426 that has been a great mower until recently. On Saturday I was mowing the yard and it started to make loud popping sounds (almost like firecrackers) and then I started to lose compression. I changed the spark plug, oil, oil filter, fuel filter, and air filter, but it didn't help. The engine is cranking and I am getting sparks, but it isn't turning over. Any ideas before I have to take it to a service center and spend money I really don't have?

:welcome: to LMF, I hope you find a solution to your problem soon! :smile:
 

EngineMan

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Check Carburetion
Before making a carburetion check, be sure the fuel tank has an ample supply of fresh, clean gasoline.
Be sure the shutoff valve, if equipped, is open and fuel flows freely through the fuel line. If fuel
fails to flow or is slow, check for plugged fuel cap vent, fuel line restriction or plugged fuel filter.
Be sure throttle and choke controls are properly adjusted.
If engine cranks but will not start, remove and inspect the spark plug.
If plug is wet, look for:
Over choking
Excessively rich fuel mixture
Water in fuel
Float needle valve stuck open
Plugged air cleaner
Fouled spark plug
If plug is dry, look for:
Leaking carburetor or intake manifold gaskets
Gummy or dirty carburetor, fuel filter, fuel lines or fuel tank
Float needle valve stuck closed
Inoperative fuel pump (if equipped)
Inoperative fuel shut off solenoid (if equipped)
A simple check to determine if the fuel is getting
to the combustion chamber through the carburetor is to remove the spark plug and pour
a small quantity of gasoline through the spark plug hole. Replace the plug. If the engine fires a
few times and then stops, look for the same conditions as for a dry plug.

Testing Fuel Shut Off Solenoid
The fuel shut off solenoid is controlled by the equipment ignition switch. With the switch OFF,
the solenoid plunger closes, stopping the fuel flow at the fixed main jet. With the switch in the
ON and START positions, the solenoid plunger opens, allowing normal fuel flow. If operating
properly, the solenoid will click when the switch is turned ON and OFF.

Check Compression..!

Possible Causes for Poor Compression:
• Loose cylinder head bolts
• Blown head gasket
• Burned valves, valve seats and/or loose
valve seats
• Insufficient tappet clearance
• Warped cylinder head
• Warped valve stems
• Worn bore and/or rings
• Broken connecting rod
 

chance123

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Loud popping noise? Is the sound coming from the exhaust or the carb (air filter)
 

ego_id

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And friend of mine and I took the casing of the engine off to see if there was anything else going on and we spotted the piston looks bent. Any idea about what it would cost to replace? It is a Briggs and Stratton 20hp 12volt.
 

chance123

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And friend of mine and I took the casing of the engine off to see if there was anything else going on and we spotted the piston looks bent. Any idea about what it would cost to replace? It is a Briggs and Stratton 20hp 12volt.

Huh?? Can you post a photo?
 

Rivets

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I you post the engine model numbers it would help us give you an estimate. Pictures would also help, as many of us would like to see what you mean by a bent piston. I for one cannot remember seeing one.
 

flv819

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Loud popping noise? Is the sound coming from the exhaust or the carb (air filter)

I'm no expert but, what he describes reminds me of when the timing was off on another mower I had, and, in the past, had cars with similar problems :smile:
 
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