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The timing is off, check your flywheel key and replace it if it is partially sheered this will throw off your spark to be little or non at all. Assuming it has electronic ignition the only three parts you need to produce correct time are cam to crank timing mark match up [for proper ignition timing ] and a solid flywheel key to line up the flywheel and crank for proper spark build up between coil and magnets on flywheel .Oil out your exhaust could be from too much oil,a plugged vent tube from crank case vent to carburetor will cause crank case pressure to push oil out of the engine through seals,exhaust valve guides up into combustion chambers too ,If the pressure gets too great it can blow a motor up .I am susspecting the valve timing is off ,The oil coming out the exhaust at the far side of what I believe to be going on without seing it in person, could be a bad ring but doubtful if it was maintained reasonably well .
How to Identify and Fix Common Gardening Problems ?
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A spark plug that is damaged, worn, or has an improperly set gap between its electrodes creates a weak spark. As a result, the fuel may not ignite in the cylinder, but it might ignite when it reaches the hot exhaust muffler. The result is a loud backfire.
@hotwheels , Leroy ,Causes of backfire on start up, bad fuel, frayed/damaged plug wires(Shorting out), valve damage, valve adj.,valve push rod damaged, ignition/wires shorting, coil shorting/faulty, restricted exhaust, flywheel key damage(allowing timing to be out), dirty/faulty/adj.
If your lawn mower begins to backfire and does not start, it is most likely due to a faulty fuel system. It`s possible that the gas is old and has gone bad, or that there is water in the tank. In either case, you`ll need to drain and replace the fuel in the gas tank.
Low fuel pressure can cause a backfire when there`s too much air and not enough fuel in the combustion chamber. This can be rectified on lawn mowers with speed settings by simply increasing the speed and thus increasing the fuel supply. Another possible cause is a failing fuel pump or even an old fuel filter.
Another possible cause of your backfire is a spark plug refusing to “spark” when the exhaust valve opens. If the air/fuel mixture has become too rich, unburned fuel is left in the exhaust system. The misfired spark plug ignites the rich air/fuel mixture, causing a loud “bang” in the tail pipe.
Assuming all of your plugs and wires are in the correct locations and you haven`t messed with the timing at all, then the most common cause of backfiring through the carb (spitting or coughing) is in the morning when a carb`s air/fuel mixture is a bit too lean. This usually goes away once the engine warms-up.
A backfire could be the first sign your car needs maintenance or repairs. Typically, a single backfire won`t damage your car`s engine, but repeated backfires could harm your exhaust system, including expensive catalytic converters.
There`s a variety of factors that can cause your car to backfire, but the most common ones are having a poor air to fuel ratio, a misfiring spark plug, or good old-fashioned bad timing.
The spark inside the chamber may not burn up all the fuel, allowing a little extra gasoline vapor to enter the exhaust, and lead to a backfire. This can be caused by a faulty mass airflow sensor or a clogged engine air filter “choking” the engine and not allowing enough oxygen to flow into it.
If too much fuel is added to the engine, it may not all burn up before the exhaust valves open — letting unburned gasoline into the red-hot exhaust headers, where it can combust and lead to a backfire. Too much fuel could be getting into your engine due to damaged and leaking fuel injectors or bad engine sensors.
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Diagnosing possible pto issue – Toro Zero Turn Rider 74366 Lawn Mower Tractor Rider Ztr
Check plug on the pto itself.located under the mower near the rear end. contacts probably have dried dirt and mud. if that don’t work, tap it with a hammer,it may be just stuck.Thats what I did and it been working ever since. Hope this helps someone.Let me know.
<!– from fixya rte –>Rj19lm plug gap for a 195cc 4cyl lawnboy – Lawn-Boy lawnboy" Mower Blade 21"
As a starting point in my shop i always use 0.30 in. For all my mowers
Gas in the oil in my craftsman 17.5 riding mower
You have a bad antibackfire valve. It is located on carburator below the fuel bowl. You can replace it, or as I advise others, install an inline shutoff valve. Turn the fuel valve on to start it, then turn it off when you shut the engine down.
How do I unstick the parking break on my Cub Cadet 50 in. Zero turn? It is stuck in the off position and will not even start unless the parking break is on. Thanks
Check your brake cables. One if not both are frozen in their housing,
Why does my mower not start?
Turn the deck PTO off .
Craftsman 22hp lawn tractor when its hot i loose half the power and backfires on cold months it run fine …brigs and stratton engine
Not a expert just trying to help,, sounds like you have heat problem with the carb or the fuel line,,make sure all the heat sheids are there,, if not repllace them,,cause it will cause the gas to try to vapor lock. hope this help you
I have trouble starting a toro walk behind mower
All, I thought my carb was shot, so I replaced it. Still, start but no run (and had to use starting fluid). THEN!!! I noticed the spring to the “rev limiter” (just below and towards rear of carb) was not “tight”. The stupid bracket that holds the end of that spring had been bent down ~1/16″ and that caused all this heartache. CHECK YOUR REV LIMITER!!!
My dls 3500 mower will not start at all, I charged the battery but the engine wont even turn. All the wiring and fuses seem to be ok
I had the same problem. I replaced the wiring harness for a short fix, corrosion in the terminals that connect to ignition switch. This worked for a while. Then replaced ignition switch this also worked for short time. Now I just open the hood to reach behind the ignition switch and wiggle wires while turning key to start until it starts keep wiggling to get good contact. If it won’t stop after it starts, wiggle wires after you turn the key to off. It will stop.