[SOLVED] What Makes My Poulan 15.5 Lawn Tractor Back Fire And Not Start For Some Time After It Back Fires.it Will Do This When I First Start It Up For T...

he first hour and then run ok after that. i just got if, but it is about 2 years old and in good condition. thank you don.
38-Inch Steel Deck 15.5 HP Briggs & Stratton I/C Engine With…

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TYhe valves need to be adjusted

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Carburetor adjustment may not be properly set for correct engine performance. Anti-afterfire solenoid may not be working properly.

Disconnected, dirty or fouled spark plugs are common causes for engines that won`t start. For small engines, spark plugs typically need to be replaced every season or after 25 hours of use. You should also check to make sure the spark plug gap is set correctly.

If your Briggs & Stratton engine has a spark but won`t run, then it is most likely a problem with the gas or air intake in the engine. The spark on the spark plug ignites the gas in the piston, but if the air filter is clogged or the gas can`t flow, then the engine won`t start.

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.

Some other typical reasons engines fail to start include:

Low or discharged battery. Corroded or loose battery cables. Starter motor relay failure. Ignition switch failure.

Bad or dead battery

The most common reason cars don`t start is a dead or faulty battery. Even though most cars run on gasoline, they all require electrical power to function. The starter that cranks your engine to start requires an electrical signal to fire.

A working pump will squirt fuel into the carburetor. However, if no fuel appears, then verify the tank has gas and check both the fuel line and fuel filter for blockages. Inspect the fuel pump visually. If fuel is dripping, the diaphragm is faulty and you need a new pump.

What causes fuel to leak into my engine oil? The fuel shut-off valve isn`t closed properly. Fuel float in the carburetor being stuck in the open position due to gumming (caused by stale fuel) or debris.

@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.

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.

Backfires

Touching back on air to fuel ratios, a vacuum leak will likely make your engine run “lean” (too much air.) This means the engine cannot efficiently ignite fuel in the combustion chamber. When fuel builds up in the cylinders and combustion occurs, it will expel a backfire.

Backfire, or more accurately “after fire” when it occurs when stopping an engine, is caused by unburned fuel/air mixture being ignited by the heat of the muffler.

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MY POULAN PRO 6.5 WONT START….nEED TO REPLACE SPARL PLUG BUT DO NOT KNOW ‘right one”..

ANSWER : Take the old plug out, any auto store should be able to match it up.

Gary

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What makes my poulan 15.5 lawn tractor back fire and not start for some time after it back fires.it will do this when I first start it up for the first hour and then run ok after that. i just got if, but it is about 2 years old and in good condition. thank you don.

ANSWER : TYhe valves need to be adjusted

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I have a Poulan push mower that after mowing in a ditch started making a loud noise and running rough. It almost sounded as if metal was hitting metal. The mower was vibrating more than normal. I checked under the mower and nothing is hitting. After a few times of stopping the mower engine because it sound as if it is going to die down the mower will not start now. The shaft does not appear bent and the blade appears ok. The mower has oil, a good spark plug and a clean air filter. It was running fine until that moment. I did not see anything that I hit but it is possible I hit something in the ditch like a pine cone or branch. What could the problem be and how would I go about fixing it?

ANSWER : If you are sure the oil level is correct then it sounds like it’s about to die, unfortunately. A pine cone shouldn’t cause any damage, but a large branch may do so. Was it smoking before you shut it down? The vibration could be caused from a bent blade. It could also be caused from a part breaking in the motor. I wish I could have given you better news!

Good Luck,

Jim

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Lawn mower will start and run for 5 seconds and shut down

ANSWER : Will it stay running with your choke on? if so then clean your carb. if not then look for a blockage from tank to carb. ie fuel shut off, deteriorated fuel line. plugged filter etc

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I have trouble starting a toro walk behind mower

ANSWER : 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!!!

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Poulan riding mower starts and runs for a few minutes then “chokes out” and stops running, why? If I let it sit for about 30 minutes I can restart it and finish the lawn. Now it runs for a few minutes chokes out and will not restart.

ANSWER : If you have already changed your fuel filter and spark plug, look at your fuel tank cap. The breathing holes may be clogged with dirt or debris preventing good fuel flow. I happened to spend $150 bucks for this $5 fix. Hope this helps.

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My poulan pro 42cc is hard to start ,,, its1 year old an i’m not sure if its worn out from alot of use or if its with the ignition

ANSWER : Throw it out and buy a new one this is a throw away scoiety we live in due to cheap *** chinese **** oh yeah go green

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I want to put a fuel cut-off valve on my poulan lawn tractor. I have a warranty and I don’t know if that will void my warranty or not. I also have insurance on the tractor. If I put anything on the tractor will that void my warranty?

ANSWER : No, not something simple as a fuel cutoff valve,but
to be sure you can always call where you bought your mower from and ask ,or call poulan service center,or a known warranty service center in your area that would honor a problem if ever needed.

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