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LawnMachines 300e Mower won't start-- Choke?
#1
R
ryantriestofixstuff
R
ryantriestofixstuff
Hey y'all, recently picked up a new lawn mower from a friend that did not start. It is a Lawn Machines 300E Briggs and Stratton mower. I thought it would be an easy fix, but I am stumped. I checked the spark plug and it seems fine. Not sure what to try next. I thought it might be the choke being stuck open but that ended up not being the case.
If you have an ideas let me know.
If you have an ideas let me know.
#2
Scrubcadet10
Scrubcadet10
That's not the choke, that is the throttle shaft, governor link and governor arm, which is connected to the governor inside the engine. and when the engine is off it sits at wide open.. it maintains the engine speed and applies throttle when the engine is in heavy grass and needs more fuel.
You should have a primer bulb on the air filter cover you took off. a big red one.
You should have a primer bulb on the air filter cover you took off. a big red one.
#3
R
ryantriestofixstuff
R
ryantriestofixstuff
Well now everyone knows that I know next to nothing about these things. What other things should I try to figure out what is wrong with my mower?That's not the choke, that is the throttle shaft, governor link and governor arm, which is connected to the governor inside the engine. and when the engine is off it sits at wide open.. it maintains the engine speed and applies throttle when the engine is in heavy grass and needs more fuel.
You should have a primer bulb on the air filter cover you took off. a big red one.
#4
Scrubcadet10
Scrubcadet10
well first lets see if it has spark.
If you have an carburetor cleaner (that is NOT non-flammable) and/ or starting fluid, or even a bit of gasoline, sprayed right into the carb for about a 2 second burst should be enough for it fire up, so spray a starting fluid into the carb, try to start, if it runs then dies, fuel delivery issue, either the carb still needs cleaned or the gas is bad/ water contaminated.
however this one is a choke version, not primer type.
now if it doesn't start at all, i would be looking for spark...remove the top engine cover (3 10mm screws) you'll see the ignition coil, and a small black wire going to the back of the engine, unplug that wire, it is the Kill wire.
try to start with that wire unplugged, repeat the earlier steps, and if it starts with the wire unplugged, there is an issue with the kill/brake assembly at the back of the engine or the wire insulation is rubbed off and shorting to ground (mower)
if it still doesn't start with the wire unplugged, bad coil.
** however i wouldn't mess with over sizing that jet
If you have an carburetor cleaner (that is NOT non-flammable) and/ or starting fluid, or even a bit of gasoline, sprayed right into the carb for about a 2 second burst should be enough for it fire up, so spray a starting fluid into the carb, try to start, if it runs then dies, fuel delivery issue, either the carb still needs cleaned or the gas is bad/ water contaminated.
however this one is a choke version, not primer type.
now if it doesn't start at all, i would be looking for spark...remove the top engine cover (3 10mm screws) you'll see the ignition coil, and a small black wire going to the back of the engine, unplug that wire, it is the Kill wire.
try to start with that wire unplugged, repeat the earlier steps, and if it starts with the wire unplugged, there is an issue with the kill/brake assembly at the back of the engine or the wire insulation is rubbed off and shorting to ground (mower)
if it still doesn't start with the wire unplugged, bad coil.
** however i wouldn't mess with over sizing that jet
#5
R
ryantriestofixstuff
R
ryantriestofixstuff
Alright Ill give it a shot. Thank youwell first lets see if it has spark.
If you have an carburetor cleaner (that is NOT non-flammable) and/ or starting fluid, or even a bit of gasoline, sprayed right into the carb for about a 2 second burst should be enough for it fire up, so spray a starting fluid into the carb, try to start, if it runs then dies, fuel delivery issue, either the carb still needs cleaned or the gas is bad/ water contaminated.
however this one is a choke version, not primer type.
now if it doesn't start at all, i would be looking for spark...remove the top engine cover (3 10mm screws) you'll see the ignition coil, and a small black wire going to the back of the engine, unplug that wire, it is the Kill wire.
try to start with that wire unplugged, repeat the earlier steps, and if it starts with the wire unplugged, there is an issue with the kill/brake assembly at the back of the engine or the wire insulation is rubbed off and shorting to ground (mower)
if it still doesn't start with the wire unplugged, bad coil.
** however i wouldn't mess with over sizing that jet
#6
S
slomo
S
slomo
How about some engine numbers?
Easy spark check. Stick you finger into the spark plug boot. Pull the rope. Report back here if you have spark. Just kidding.
What exactly did you check on the plug and how did you do it? Did you Ohm it out with a meter? If so should be 4-6K Ohms from boot to center conductor. Assuming you have a resistor plug that is.
Is the carb getting fuel TO the inlet pipe from tank? Fuel tank full of grass slash dirt slash grit and grime?
Like Scrubcadet10 said, spray something flammable into the carb. Pull the rope. See if it fires off for a few seconds. Report back here with your findings.
slomo
Easy spark check. Stick you finger into the spark plug boot. Pull the rope. Report back here if you have spark. Just kidding.
What exactly did you check on the plug and how did you do it? Did you Ohm it out with a meter? If so should be 4-6K Ohms from boot to center conductor. Assuming you have a resistor plug that is.
Is the carb getting fuel TO the inlet pipe from tank? Fuel tank full of grass slash dirt slash grit and grime?
Like Scrubcadet10 said, spray something flammable into the carb. Pull the rope. See if it fires off for a few seconds. Report back here with your findings.
slomo
#7
B
Born2Mow
B
Born2Mow
- The place to start with any engine you don't know the full history and age is all new fuel.
- Then the traditional: fuel, fire, and compression.
#8
R
ryantriestofixstuff
the engine is a 08P5020055F1
serial: 17 0427 54 29274
Ill spray something into the carb.
R
ryantriestofixstuff
I just checked the spark plug. It is not a resistor plug, its an E3.20. It had a resistance of over 100k ohms which is not right hah. Ill blow some air through the gas tank to see if that's the issue. I don't have the equipment to test the spark plug so I pulled it out and checked to see if it was corroded or anything. It looks pretty new so unless its an internal thing, it seems okay.How about some engine numbers?
Easy spark check. Stick you finger into the spark plug boot. Pull the rope. Report back here if you have spark. Just kidding.
What exactly did you check on the plug and how did you do it? Did you Ohm it out with a meter? If so should be 4-6K Ohms from boot to center conductor. Assuming you have a resistor plug that is.
Is the carb getting fuel TO the inlet pipe from tank? Fuel tank full of grass slash dirt slash grit and grime?
Like Scrubcadet10 said, spray something flammable into the carb. Pull the rope. See if it fires off for a few seconds. Report back here with your findings.
slomo
the engine is a 08P5020055F1
serial: 17 0427 54 29274
Ill spray something into the carb.
#9
S
slomo
S
slomo
On the plug, 100K Ohms is bad. Unless you are touching carbon with the probes giving you that high reading. Get an NGK or Champion plug for your engine. Waiting on the flammable spray test.
slomo
slomo
#10
R
ryantriestofixstuff
R
ryantriestofixstuff
The spark plug was pretty clean so it must just be a bad spark plug. I'm going to re-assemble it now and do the spray test.On the plug, 100K Ohms is bad. Unless you are touching carbon with the probes giving you that high reading. Get an NGK or Champion plug for your engine. Waiting on the flammable spray test.
slomo
#11
R
ryantriestofixstuff
R
ryantriestofixstuff
I got it to start and run for a little bit, I already looked at the carburetor and it looked clean ( no blocks in the jets) the spark plug seems fine if its firing like that. What should i do next?On the plug, 100K Ohms is bad. Unless you are touching carbon with the probes giving you that high reading. Get an NGK or Champion plug for your engine. Waiting on the flammable spray test.
slomo
#12
Scrubcadet10
Scrubcadet10
Carbs can look clean and still be dirty.
How did it run when it was running? did start up after you turned it off or did it die?
How did it run when it was running? did start up after you turned it off or did it die?
#13
R
ryantriestofixstuff
R
ryantriestofixstuff
I did the video that you sent me to try clean it. I don't have anything to clean it well. I assume I cant use water to clean it, but I don't have anything else that has the power.Carbs can look clean and still be dirty.
#14
R
ryantriestofixstuff
R
ryantriestofixstuff
I pulled the gas out and it looks like there's quite a bit of dirt in it.I did the video that you sent me to try clean it. I don't have anything to clean it well. I assume I cant use water to clean it, but I don't have anything else that has the power.
#15
R
ryantriestofixstuff
R
ryantriestofixstuff
It died almost immediately, but this happened because I didn't have the fuel tank attached.Carbs can look clean and still be dirty.
How did it run when it was running? did start up after you turned it off or did it die?
#16
Scrubcadet10
Scrubcadet10
you can clean out the tank with water, just put a little bit in, swirl out around dump it, repeat, until clean, then a put a small amount of gasoline in it, swirl it around an dump it out, and allow it to dry in the sun for a little while.I pulled the gas out and it looks like there's quite a bit of dirt in it.
#17
S
slomo
S
slomo
You can use all the water you want. Your wife's dishwasher is a great parts washer. Dump out on final and spray with WD-40 or fresh fuel as Scrub said.
slomo
slomo
#18
R
ryantriestofixstuff
R
ryantriestofixstuff
you can clean out the tank with water, just put a little bit in, swirl out around dump it, repeat, until clean, then a put a small amount of gasoline in it, swirl it around an dump it out, and allow it to dry in the sun for a little while.
Alright, I just washed out the tank, seems like it is flowing a bit better. Should I let dry, re-assemble, and try start the mower? Or should i really clean the carb. (stick it in the dishwasher hah)You can use all the water you want. Your wife's dishwasher is a great parts washer. Dump out on final and spray with WD-40 or fresh fuel as Scrub said.
slomo
#19
S
slomo
I hope you are not laughing at the dishwasher tip. Disassemble the carb. Float, needle and seat, gaskets and jets. Put the dishwasher on hot potscrubber mode. It will come out like new. Blow out with compressed air.
slomo
S
slomo
Remove all the soap and water. WD-40 is a water displacer. Spray it in the tank and shake around. Make sure you have good flow out of the tank. Clean the carb best you can.Alright, I just washed out the tank, seems like it is flowing a bit better. Should I let dry, re-assemble, and try start the mower? Or should i really clean the carb. (stick it in the dishwasher hah)
I hope you are not laughing at the dishwasher tip. Disassemble the carb. Float, needle and seat, gaskets and jets. Put the dishwasher on hot potscrubber mode. It will come out like new. Blow out with compressed air.
slomo
#20
B
bertsmobile1
B
bertsmobile1
Spark plugs no longer have a glazed insulator on the inner electrode.
So once the spark tracks down the insulator the plug is trash
Modern fuel ( which is not petrol ) is conductive at compression pressures
So once the spark tracks down the insulator the plug is trash
Modern fuel ( which is not petrol ) is conductive at compression pressures
#21
S
Smokeeater
S
Smokeeater
It’s either spark which you’ve checked, air filter clogged or fuel not getting through. Odds are it’s a fuel issue. Clean out the carbHey y'all, recently picked up a new lawn mower from a friend that did not start. It is a Lawn Machines 300E Briggs and Stratton mower. I thought it would be an easy fix, but I am stumped. I checked the spark plug and it seems fine. Not sure what to try next. I thought it might be the choke being stuck open but that ended up not being the case.
If you have an ideas let me know.
#22
J
Joed756
J
Joed756
I'm not sure what this means, but you should consider a new plug. And yes, they do fail internally. I have seen plugs (usually Champion) that look just fine and spark just fine until compression is applied in the cylinder, then things expand and contract and you end up with a spark going around the insulator to ground. I've seen this with brand new champions in automotive tests. Simply try to start your engine in the dark, you'll see if there is an errant spark.The spark plug was pretty clean so it must just be a bad spark plug. I'm going to re-assemble it now and do the spray test.
#23
gamma_ray
gamma_ray
I really like Steve's videos and have watched many of them before. He's down to earth and explains things clearly, both rudimentary fixes and quirks he's discovered, such as this B&S carb main jet fix.well first lets see if it has spark.
If you have an carburetor cleaner (that is NOT non-flammable) and/ or starting fluid, or even a bit of gasoline, sprayed right into the carb for about a 2 second burst should be enough for it fire up, so spray a starting fluid into the carb, try to start, if it runs then dies, fuel delivery issue, either the carb still needs cleaned or the gas is bad/ water contaminated.
however this one is a choke version, not primer type.
now if it doesn't start at all, i would be looking for spark...remove the top engine cover (3 10mm screws) you'll see the ignition coil, and a small black wire going to the back of the engine, unplug that wire, it is the Kill wire.
try to start with that wire unplugged, repeat the earlier steps, and if it starts with the wire unplugged, there is an issue with the kill/brake assembly at the back of the engine or the wire insulation is rubbed off and shorting to ground (mower)
if it still doesn't start with the wire unplugged, bad coil.
** however i wouldn't mess with over sizing that jet
#24
J
Joed756
J
Joed756
I'm not sure what this means, but you should consider a new plug. And yes, they do fail internally. I have seen plugs (usually Champion) that look just fine and spark just fine until compression is applied in the cylinder, then things expand and contract and you end up with a spark going around the insulator to ground. I've seen this with brand new champions in automotive tests. Simply try to start your engine in the dark, you'll see if there is an errant sparkThe spark plug was pretty clean so it must just be a bad spark plug. I'm going to re-assemble it now and do the spray test.
Alright Ill give it a shot. Thank you
I just checked the spark plug. It is not a resistor plug, its an E3.20. It had a resistance of over 100k ohms which is not right hah. Ill blow some air through the gas tank to see if that's the issue. I don't have the equipment to test the spark plug so I pulled it out and checked to see if it was corroded or anything. It looks pretty new so unless its an internal thing, it seems okay.
the engine is a 08P5020055F1
serial: 17 0427 54 29274
Ill spray something into the carb.
#25
J
Joed756
J
Joed756
Dude, seriously, replace your plug. It costs $5, it's the likely culprit and a simple job. Forget what it looks like, that doesn't tell you much unless you are checking the electrode for engine diagnosis, you are not doing that. Pop in a new plug and watch your worries drift away.
#26
R
Ronni
R
Ronni
Here is a video that should help you.Hey y'all, recently picked up a new lawn mower from a friend that did not start. It is a Lawn Machines 300E Briggs and Stratton mower. I thought it would be an easy fix, but I am stumped. I checked the spark plug and it seems fine. Not sure what to try next. I thought it might be the choke being stuck open but that ended up not being the case.
If you have an ideas let me know.
#27
S
slomo
slomo
S
slomo
"How" did you check the spark plug?Hey y'all, recently picked up a new lawn mower from a friend that did not start. It is a Lawn Machines 300E Briggs and Stratton mower. I thought it would be an easy fix, but I am stumped. I checked the spark plug and it seems fine. Not sure what to try next. I thought it might be the choke being stuck open but that ended up not being the case.
If you have an ideas let me know.
slomo
#28
S
slomo
S
slomo
How about a valve adjustment check? Pull the head and de-carbonize the combustion chamber? Clean the block cooling fins all the way around. Get an inline spark tester. Lastly best time to check spark is in the dark or low light conditions. Blue spark is good, orange is weak slash bad.
slomo
slomo
#29
H
Hilton43
H
Hilton43
Spray some starter fluid in the carburetor and try to start it. If it runs for a short time and then dies it is not getting fuel. If it doesn’t then check the compression, remove the plug and put your thumb over the hole and see if it blows your thumb away. An engine needs fuel,air, compression and a spark to run. When you find which one is missing you will know what to repair.Hey y'all, recently picked up a new lawn mower from a friend that did not start. It is a Lawn Machines 300E Briggs and Stratton mower. I thought it would be an easy fix, but I am stumped. I checked the spark plug and it seems fine. Not sure what to try next. I thought it might be the choke being stuck open but that ended up not being the case.
If you have an ideas let me know.
#30
P
Pecosbill
P
Pecosbill
Sometimes we over analyze and make these things more complicated than they may need to be. I’ve found that in most cases where a small engine won’t start it’s not the electrical system, although those items most certainly go bad. When a mower has been sitting unused for a while and there was even a small amount of gasoline left in the tank that gasoline, especially if it contains ethanol, will evaporate in the carb and leave behind a tiny bit of residue which will clog shut the jet on the carb. If this is the case, take the carb apart just enough to see the jet and run a very thin piece of wire through the jet, removing the clog. Put it back together and try to start it, without the air cleaner.
If the air cleaner has any dirt on it, clean or replace it. It may very well have been a dirty air cleaner that caused the previous owner to have trouble starting the engine and may well be why he just let it sit for a long time. When the engine sat unused, gunk developed in the carb from evaporation. I have found that these two things are the usual culprits in most of my starting issues.
If the air cleaner has any dirt on it, clean or replace it. It may very well have been a dirty air cleaner that caused the previous owner to have trouble starting the engine and may well be why he just let it sit for a long time. When the engine sat unused, gunk developed in the carb from evaporation. I have found that these two things are the usual culprits in most of my starting issues.
#31
R
raider820
R
raider820
I have read the comments and saw that you did get it to start by spraying gas into the carb. With that, I think you have pretty much eliminated the spark and compression issues and what you are left with is a fuel issue. So you need to determine is fuel flowing from the tank, flowing through the fuel line to the carb, then flowing into the carb. So, I would check things in this order: 1. Get a small tray or cut soda drink bottle to catch fuel. 2. Disconnect the fuel line at the tank and make sure you have a good fuel flow. 2. If you have good flow from the tank, reconnect and then disconnect at the carb and make sure you have good flow through the hose. Sometimes the inner fuel line will deteriorate and the inner hose will get pushed back up into the line when the line is pushed back on the nipple at the tank or carb and block the line. 3. If you have good fuel flow going into the carb, then the issue is the carb. In my opinion, those carbs suck. The jets in it can get clogged and no matter what you do, sometimes they never clear up. But before messing with the jets, put some gas in the tank and allow it to flow to the carb. Then remove the carb and catch the gas in a bowl or pan make sure the carb bowl is full of fuel and that the float is not sticking and the valve is not blocked. 4. If the flow is all good, then you can move on to cleaning the jet. If it still will not start normally but starts when you spray gas into the carb, I would order a new carb because it is cheaper to order the whole carb than just the main jet. You can find the cheap Chinese versions on eBay for 10-12 bucks.
#32
R
ryantriestofixstuff
R
ryantriestofixstuff
Hey yall, got it running! Something stuck in the carb.
I'm not sure what this means, but you should consider a new plug. And yes, they do fail internally. I have seen plugs (usually Champion) that look just fine and spark just fine until compression is applied in the cylinder, then things expand and contract and you end up with a spark going around the insulator to ground. I've seen this with brand new champions in automotive tests. Simply try to start your engine in the dark, you'll see if there is an errant spark.
Spray some starter fluid in the carburetor and try to start it. If it runs for a short time and then dies it is not getting fuel. If it doesn’t then check the compression, remove the plug and put your thumb over the hole and see if it blows your thumb away. An engine needs fuel,air, compression and a spark to run. When you find which one is missing you will know what to repair.
Hey yall, got it running! Something stuck in the carb. It smokes a crap ton when it does start, but it runs nicely afterwards! Does anyone know why its smoking so much?How about a valve adjustment check? Pull the head and de-carbonize the combustion chamber? Clean the block cooling fins all the way around. Get an inline spark tester. Lastly best time to check spark is in the dark or low light conditions. Blue spark is good, orange is weak slash bad.
slomo
#33
Scrubcadet10
Scrubcadet10
is it blue smoke? black smoke?
#35
S
slomo
Could be a carb needle sticking open to bad piston rings and or piston.
Remove the block vent hose that runs to the carb. Start the engine and see how much smoke or oil vapor comes out.
slomo
S
slomo
White smoke normally is water burning off. Guessing yours is oil, most likely. Check oil level on flat ground. Level needs to be exactly at the full mark. Not over nor under.white smoke for like a second then none.
Could be a carb needle sticking open to bad piston rings and or piston.
Remove the block vent hose that runs to the carb. Start the engine and see how much smoke or oil vapor comes out.
slomo