Small Engines Won't Start and Guides Don't Help
Users are experiencing common issues with small engines, including starting problems, fuel leaks, and mechanical noises. Many are seeking advice on troubleshooting and repair techniques.
SOURCES (60)
“I have had the same mower for 8 years and have never taken the carb off or cleaned it in that entire time. Change the air filter and oil once per season, same spark plug. Starts on first pull every spring like there is nothing.…”
“Got this toro lawnmower that only runs good when warm. Auto choke hates cold starts (ignore the wind chimes in the video I know they're annoying) submitted by /u/idontknow2729 [link] [comments]”
“Can anyone tell me what causes a mower to not turn over/crank if the battery is new? Headlights come on, but there is no crank when I turn the key. submitted by /u/ItsTheEndOfDays [link] [comments]”
“It only starts with the choke fully out and the moment i press the throttle thats when it dies, also sounds kind of rough. Ive just gone through the carb and replaced all the diaphrams and gaskets, i also checked the needle and went through the jets and all seems well. Is this just a simple idle or mix adjustment? submitted by /u/Kitchen-Quantity6961 [link] [comments]”
“Not sure if this is the right sub or not. Hopefully so. Probably going to cross post just in case. John Deere LA145 mower with Briggs and Stratton engine. Backstory: So last week my 12 (almost 13) year old filled this John Deere riding mower with my weedeater gas (can’t remember if it was 50:1 or 40:1), and proceeding to cut the front and back yard. 1/2 acre lot with a house on it. Kid is new to cutting grass and not quite efficient at cutting in one go, so may have taken a little longer than th”
“I’ve been messing with this thing all morning and can’t seem to get it started. The fuel lines have fuel The vacuum line is pulling, and the fuel filter isn’t clogged even when I have it full throttle and the choke on it isn’t starting the video that you see is the last time it started and the only thing that I did was take off the fuel line and put it back on the carburetor to see if there was fuel coming out of the line submitted by /u/Mrstoneybaloni [link] [comments]”
“25cc craftsman weed whacker didn’t run at all, installed new Amazon carb. Now it starts and runs strong for 20 minutes or so, then slowly sputters and dies like in the video. Both times it happened shortly after stopping to put gas in the tank, not sure if that’s related or just a timing thing. It will restart and run for shorter and shorter times until it won’t start at all. Then it will start right up the next day and do it all over again. Not sure where to start. Thoughts? submitted by”
“Any idea based on the sound of the sputtering why my Cub Cadet 139cc push lawnmower no longer runs? My dad had replaced the spark plug, cleaned the carb bowl, checked fuel lines, and added new fuel. Now we're thinking it's possibly the last piece, the ignition coil? submitted by /u/nov_very_own [link] [comments]”
“When I start my mower, it always starts and runs for like 5 seconds. It feels like it's sputtering a little and then coming up to "true speed". However that's the moment it starts dying down, too. It also ststts dying too fast for me to pull the choke out. This is actually the second start of the day(Between the first start and this one abiut 5 hiurs passed). Afaik you should be able to restart a flooded engine after like 10-15 minutes, when it died from running too rich. You c”
“I've got this DR brush mower with a briggs and stratton 16.5 hp engine that I got running after cleaning the Carb but after doing so it refused to change gear and now won't start after messing with the shift lever I assume because it now thinks it's in gear. The lever moves a bit but doesn't seam to change the gear nomatter how much force I but into it and I know the cables aren't snapped. With some I research I read there's supposed to be something on the shift in the th”
“I’m going to clean out the carb, could it be anything else? 1978 Honda CB400 hondamatic submitted by /u/Woe_Mitcher [link] [comments]”
“I have a Walbro W-8 carburetor that seems to have a tendency to flood. If I pull the starter 2–3 times without the engine firing, it usually won’t start until I remove and dry the spark plug. Yesterday, I squeezed the fuel primer bulb and noticed fuel leaking out of the carburetor. I had to squeeze fairly hard, but not extremely hard. Could this be a sign that the pop-off pressure is too low, or that there is a problem with the metering needle/diaphragm system? Or is it normal for fuel to come t”
“Our Troy-Bilt Pony rear tine tiller is maybe getting up there in years. starts fine once its warm but every week the first pull takes a little more effort. choke helps but before this started it fired right up. No smoke, runs ok once going. just this slow creep of harder cold starts. Is that just age or worth chasing down a specific cause before it gets worse? submitted by /u/Loose_Performance745 [link] [comments]”
“Engine fired up first pull ran for about 1 minute then acted like it ran out of gas or the kill switch was pushed. Pulled and pulled nothing. Sprayed in some starting fluid nothing. Hit the kill swith a few times then it fired on the starting fluid but wouldn't start. Repeated this several times. I think the kill switch may be the issue. Can I remove the wires from the switch and twist them together to test if the switch is bad? submitted by /u/1chefj [link] [comments]”
“I just bought this mower in the summer of 2025- so now that I’m having issues with it is BLOWING my mind especially since it was about 2k new. I started noticing issues w the battery. I would have to jump it to crank the mower. I figured since they left them outside maybe something was wrong w it and decided I’d replace it when I couldn’t jump it anymore. So all last summer ran great besides that. This summer. Whoa. She’s put me thru hell and back. First- the belt keeps coming off the blade enga”
“Anyone able to diagnose the issue with my weed wacker not starting ? It was running at half power, then I replaced the filter, spark plug and sprayed down the carb, but now it won’t start. submitted by /u/RenoKabino [link] [comments]”
“I'm going to assume that you have a 2 stroke trimmer. Often they have issues starting as they get older because the crankshaft seal wears, so you're losing compression. Get it serviced, that'll help the starting. They might say it's not worth the cost of tearing it down and fixing in which case you can justify an upgrade. The 4 stroke Honda is absolute magic. Contractor quality. Get a speed feed head, that'll fix your loading issues.”
“Did you remove the exhaust filter screen thing? How long has it been since you replaced the spark plug? Air filter? How old is the trimmer? Also, if its a 2 stroke, its designed to be ran at full throttle while its running. Something to keep in mind”
“Your valves are out of adjustment. Get a set of feeler gauges and adjust them. Takes like 5-10 minutes. Running full throttle is killing the string.”
“75 % of the problems I see are fuel related. Try buying a new head for the trimmer”
“The fucker takes 20 minutes to prime and start after yanking on it around 50 times. Finally when I get it running I have to pretty much run it at full throttle to keep the engine running. Meanwhile the line lasts about 10 feet before it breaks, tangles or the feeder simply stops working. Forcing me to shut the engine off, spend ANOTHER GODDAMN 20 MINUTES restringing the thing. Only for me to yank on it another 20 times to get it running again. Meanwhile I must not have strung it to a micron of i”
“The motor will run on ether but I can't get it to even pop a little otherwise. I've run it through the sonic cleaner but I'm hesitant to pull it apart due to wrecking gaskets and not being able to find replacements. submitted by /u/PhantomTurk [link] [comments]”
“I picked up this blower recently and was told it wouldn’t stay running. I put some fuel in it and tried starting it and sure enough it would run but only shortly before dying. I took the carb off and gave it a good cleaning with carb spray and I put the thing back on. when I went to start the blower it still would start but not stay running. I pulled the carb and double checked before reassembling again but to no avail. Any suggestions? submitted by /u/SorryBed7466 [link] [comm”
“Are you mulching? Bagging? Blades sharp? I bet the Toro that came with the house is several years overdue on an oil change, at least. What height are you cutting to? You want a used ride behind zero turn. Most cost effective option that still delivers professional results, and reliably. But bump that budget dude. I’d hope after your third run of using $400 mowers, you’d realize that one $1200 used mower could’ve lasted you the rest of your life”
“I am helping a friend fix his 27 ton champion log splitter. He called me to take a look at it last week. I checked everything and there is pressure. I then checked to make sure it was level, oil and hydraulic oil levels were topped off. Wouldn't start, so I examine ignition coil and nothing was happening. I checked coil and it had been chewed by mice. Ordered new one, got it installed, gapped it right to fly wheel. Put everything back together and tried and nothing. It's close to startin”
“Everytime I try to start the mower it cranks but it won’t turn over. I’ve replaced the battery, starter, the ignition coil, spark plug, fresh fuel, new fuel filter, and oil change. It has compression. No bent or broken rods. I’ve cleaned the carb. What am I missing? submitted by /u/Original_Property_89 [link] [comments]”
“No fuel getting to carburetor. Fuel shut off is powering up and moving. New fuel pump. Ran out of fuel, won’t stay running now. Fuel filter has fuel in it submitted by /u/Johndeere1040 [link] [comments]”
“Hey guys this is my first post here. I'm at my wits end right now and would love some knowledge. I have a husqvarna 330lk weedeater I bought new a year and a half ago, it worked fine up until I feel I ran it a bit too hard. The week after I ran it hard it would not start I put fresh gas in it and it still didn't start. A week later tried to start it and to my surprise it started, but it wouldn't stay idle but for a few seconds unless i pressed the gas. Fast forward to a few weeks lat”
“Newer Exmark laser Z mower with starting issues. I have replaced the battery twice, so I know it can’t be the battery. Any ideas? submitted by /u/Life_Yak_8420 [link] [comments]”
Fixable? submitted by /u/TallTelevision4121 [link] [comments]
“I got this power head for free and it makes a weird noise when running. I replaced the carb, spark plug, spark arrestor and cleaned ignition coil. Sounds like a rev limiter submitted by /u/Far-Cookie7335 [link] [comments]”
“Just took carb off, cleaned it, new primer bulb but when I start, it idles very slow. If I take my finger and go back and forth with the circled part it gets up to speed but when I let off it goes back to the very slow idle. submitted by /u/Caliguy232 [link] [comments]”
“Hold the bar down on cement. The cord on the right is yanked. Sometimes you’ll have to prime the gasoline (usually a rubber button on the engine). Sometimes you also have to push the mower forward while yanking the cord back.”
“Same but with RYOBI 40v trimmer, blower and also my zero turn mower. I hope the next generation of battery lawn equipment corrects some of the current flaws, but overall I’m happy to dump gas and diesel powered stuff.”
“Hello I am having issues with this 500vt carburetor I noticed that the second carb has the idle jet sitting like it should and this other one has it sitting to the side because of this brass bit that I have no idea how to adjust I just need to know how to turn it or adjust it to have it sit right in the carb I'm pointing at it with a needle tool. The carb is for a 1984 honda ascott vt500ft submitted by /u/Jonathan127378 [link] [comments]”
“Lawn mower has annilihated my cast iron clean out riser and cap…can I DIY repair this? Tips for repair? submitted by /u/RickyReditt___ [link] [comments]”
“Help please, new to carburetors. Ran it out of gas this winter on accident, wouldn’t start after. Removed and cleaned the carb by spraying carb cleaner on all the holes. Started right up after I put it back together, ran for a few minutes, rpm starts bouncing and it dies and won’t restart. Then half an hour later leaks fuel out of a hole behind the intake screen. I just replaced the needle and seat, the old seat was falling apart. Thought this would fix the issue. Started right up, ran for a mom”
“Hello, I’m having issues with my weed eater. Seems like the next step is getting the compression tested, or trying a new spark plug even though the one I have seems to work fine. Everything I visually checked seemed fine, but I’m not experienced so take that as you will. Here’s the list of troubleshooting I’ve done so far. Thank you for any insight. Confirmed the spark plug is producing spark by grounding it against the engine while pulling the starter. Replaced the old fuel in the trimmer with”
“I took this from my dad's garage after he said he couldn't get it to crank. It's been about 10 years since he's last used it. Put some fuel directly in the cylinder and it fired up. Put gas in the tank and tried to start it and nothing. I disconnected the fuel line and turned on the valve and gas flowed through the line. I took off the carburetor and cleaned it best I could, I reattached the fuel line, opened the valve and nothing flowed into the carburetor. Did my best to blast”
“I got an old troy build mower with a briggs and stratton 725 exi engine. The issue I am having is that after it get hot, it will not start again until it cools down. If I stop mowing to take a break, I then have to wait like 10 mins to be able to start it again. Initially I thought auto choke was an issue. However, when I removed plastic covering, it looks like auto choke stays in the open position which I believe is correct. The little thermostatic "arm" thing appears to move freely.”
“Hey knowledgeable folks, I've got to replace a carb on a briggs 25hp v-twin and the new carb comes with the newer style fuel shutoff solenoid. Original was a 499809 shutoff solenoid, new will be a 499804. Pic of new style shutoff at link below. Anyone know what kind of plug this is? I'm going to have to cut off my existing plug and adapt to the new solenoid. https://m.media-amazon.com/images/I/618TG5rw5XL._AC_SY300_SX300_QL70_ML2_.jpg Thanks in advance. submitted by /u/zabcod”
“Toro timecutter mx5000 will not start properly. Turn key for about 15 seconds and it will backfire then it will finally start and runs great. But will never start until it backfires first and this can't be good on the starter. It has the Toro branded engine which I think is a 25hp Chinese lincon engine. submitted by /u/ConstructionBoth3820 [link] [comments]”
“I was trying to get my lawn mower started by clearing out some debris in the carburetor, and it did start. But it immediately started smoking heavily and shot out a lot of dirty gasoline from what I presume is the air vent, how do I resolve this? submitted by /u/Ok_Tomato_4821 [link] [comments]”
“Took my mower to the mechanic after I put old gas into it and it wouldn’t start. Mechanic said something about the metal ball in carburetor getting stuck. It has been running again since I got it back but now it runs rough. Any ideas? I will Venmo someone $5 if they can provide some insight. Thanks! 🙏🏻 submitted by /u/Esmack [link] [comments]”
“Hi all, wondering if anyone can help with this issue. Its a push button start, when I disassemble the engine it will eventually start to work and start everytime. After I leave it a day or two it's repeats the issue in the video. Any ideas as what to diagnose on it. Thanks submitted by /u/Extension_Ad1814 [link] [comments]”
“I’ve had this pressure washer for months but haven’t been able to use it because when I received it (as a gift) the springs on the carburetor were not in place. I’ve been trying to figure how they go and I’m going insane. Any help at all is greatly appreciated! submitted by /u/Happy-Demand-8804 [link] [comments]”
“hello, I put a new carb on this, cleaned the fuel tank and line and the mower fires up but immediately dies. I disconnected the auto-choke to see what it would do and it runs at full rpms. seems something is wrong with the autochoke but I can’t figure out how to fix it any help is appreciated submitted by /u/Mundane-Cucumber-922 [link] [comments]”
“So I got this free mower from a buddy when we bought the house back in April. It's pretty well mint condition, even has all the stickers still on it lol. Its been great until I ran into an issue with the plug wire. It had a small crack in it. Taped it up and it got me buy. Just installed the new ignition coil and wire with a plug that came with it. The wire didn't go all the way onto the plug and on my first test run the wire came off the plug and it backfired. So I went and got one of t”
“Unless you’re washing down the mower after each mow, there’s dust/grass clippings that’s stuck to the surface and then get into tank when you fill gas. Just have an extra carb for replacement.”
“Title is pretty self-explanatory, but I’ve been trying to get this craftsman to start for a while now it is pretty rundown, but I have change the spark plug, emptied the gas tank and refilled it. Ensure there’s oil in the lawnmower as well as just cleaning out the carburetor. One thing to know is that I didn’t use any carburetor cleaner. The carburetor looked pretty clean to me when I opened it up. I’ll provide pictures in the post but any help at all would be awesome. I know nothing about lawn”
“2006 125L. Just been the best thing. Still starts and runs fine. I broke the throttle trigger. I can’t find a replacement. I would change the throttle control housing if I could find someone who sold something that was a direct fit. Any help submitted by /u/Dry_Emotion6885 [link] [comments]”