Fuel Leaking From Air Filter

In this video, I explain the MAIN reasons for why fuel might be leaking from your carburetor. I go into a detailed explanation of how the carb works using easy to understand concepts.
The content in this video might not be applicable to your exact piece of equipment. Any damage or loss to persons or property that may result from use of information contained in this video is the sole responsibility of the user and not Brant Small Engine Repair.
Brant Small Engine Repair encourages the use of safe practices and safety equipment while working on your machines and therefore assumes no responsibility for personal injuries. The information contained in this video shall be used for informational purposes and used at viewers discretion.
On my channel. you will find repairs to many different makes and models of lawnmowers, trimmers, generators, rototillers, snow blowers, chainsaws, lawn tractors, pressure washers. If you're looking for repairs on Honda, MTD, Ariens, Husqvarna, Murray, Weedeater, Toro, Troy-bilt, Echo, Stihl, Craftsman, Mastercraft, Bolens, Brute, Firman, Generac, John Deere, Poulan Pro, Homelite, Canadiana, Noma, Remington, Powermore, Tecumseh, Briggs and Stratton, Kohler, Yardworks, Yardman, Yard Machines, etc, this is the channel for you.
Tools used in this video:
Mityvac Pressure Tester: amzn.to/3paYRYs
Fuel Line Clamp Set: amzn.to/35UOge9
Tecumseh Carb Tool: amzn.to/3SUNuSe
DISCLAIMER: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission. There is no additional charge to you!
Music: www.bensound.com

[@TingTingalingy]

You do the old 1,2,3... Type teaching. A dear friend, an older guy, he had a similar method of teaching and I learned so much from him due to this. Cheers

[@brantsmallenginerepairs]

Thanks for watching and taking the time to leave a comment. Cheers

[@stevemlejnek7073]

I found this problem with a mower. I replaced the carb with a complete new carb and the same problem occurred. It started fine with the brand new carb, then a few minutes after running, I saw gas dripping out the air filter again. Is there any other potential cause of this problem? Hard to believe a brand new carb would have the same float/seat problem.

[@brantsmallenginerepairs]

For this type of carburetor, the needle and seat is going to be your culprit. Sometimes the float gets "hung up" within the bowl and the fuel can not provide enough upwards pressure to unstick your float and/or needle. Try pushing the handle down to raise the front of the mower and then let the front drop to the ground. Do this a bunch of times. This will sometimes helps to "unstick" the float and cause it to work again. Hope this helps. Cheers

[@ragtoprita]

You are a fantastic teacher. I wish I had found you years ago when I didn't know what in the world I was doing, when things worked together only after many hours just by chance. Keep up the great work. Will send folks your way.

[@brantsmallenginerepairs]

Thanks for the kind words. Cheers

[@frankschannel2642]

Super video! I'm struggling with a leaking carb off a Yamaha 4hp outboard motor. I'm CERTAIN this will help! Thank You!!

[@brantsmallenginerepairs]

Glad it helped. Thanks for watching and taking the time to leave a comment. Cheers

[@SaxJockey]

This is by far the best explanation of carb leaks that I have seen 👍. My mower has a carb (Huayi) like the one on the left of the video (metal fuel bowl). However, the foam filter is located above the carb. I recently changed the blade, in preparation I removed the plug lead, bagged the tank cap, and tilted the deck to the right (exhaust low/tank, carb, air filter high). Fuel leaked from somewhere on the carb. As a result, I drained the tank and carb bowl to continue. The carb does not leak normally. When the machine is tipped to the side, is the float/needle valve compromised (no proper seal due to the abnormal orientation)? I assume fuel flowed from the bowl/tank through the brass inlet into the carb. It did not appear to leak onto the filter (uppermost), so assume it leaked out of the gasket between the carb and the engine. Otherwise it would have gone into the cylinder inlet valve (fortunately the piston might have been at TDC thereby closing the cylinder valves). Anyone readers had an experience such as this?

[@brantsmallenginerepairs]

You will sometimes get a bit of a fuel leak, even if you've tipped it the proper way. This is not really a big concern but if you want, you can turn off the fuel shutoff or pinch off the fuel line. This might help.

[@roadstar499]

Also debris,sitting long time and even a new carb may have metal shavings etc left in carb during manufacturing process that can cause float needle issues...floats can just stick...taking appart and inspecting and cleaning fixes issues a lot of times...you can even adjust floats to close valve sooner or later very easy,then put together and test simply by blowing air and manually moving float up and down you can note the floats postion when its open and closed...or it may not work and you can blow air through even when needle is seated all the way...

[@brantsmallenginerepairs]

Thanks for the suggestions. Cheers

[@hardcoretrout]

Thanks for sharing. I have cleaned several small engine carbs but did not understand exactly how the float functions as the inlet valve.

[@brantsmallenginerepairs]

Glad I could help. Thanks for watching and taking the time to leave a comment. Cheers

[@fernandoacosta6669]

I have that problem with my lawn mower, the carburetor was pouring gasoline through the outlet where the air filter is, I bought another carburetor but the problem continues, it is still pouring gasoline through the outlet where the filter is. I don't know what the reason would be since it's new.

[@brantsmallenginerepairs]

Sometimes aftermarket carbs can be hit or miss. If the fuel is leaking, the needle and seat are not making a good seal. Or maybe the float is stuck, not allowing the needle vale to shut off the fuel. Hope this helps. Thanks for watching and taking the time to leave a comment. Cheers

[@pastorkevinfletcher]

Thank you so much for the grear explanation. I had a pretty good idea how crave worked but your detailed explanation really helped me understand then better

[@brantsmallenginerepairs]

Glad it was helpful. Thanks for watching and taking the time to leave a comment. Cheers

[@hankleberry]

What a fantastic video. I know a fair amount about repairing vehicles, took vo-tech in high school and then worked as a service advisor for years. But never had any experience with small engines, and not a whole lot about carbs either. This was such a simple explanation and has really eased my stress. I still think I'll replace my carb in my Kohler SV600S riding mower because it's getting long in years. But this will help me justify that once I pull the carb.

[@brantsmallenginerepairs]

Glad you enjoyed the video and it helped. Thanks for watching and taking the time to leave a comment. Cheers

[@a3sully]

Where can I get parts for that carb? Every online place says parts unavailable. I don't want to buy a new carb every time it needs to be taken apart or has a bad float or needle.

[@brantsmallenginerepairs]

See my response from your question on my other video. Cheers

[@robertjohn4539]

My lawnmower carb was leaking . I had not used this mower for 3 years. The motor control symbols were gone . I naturally assumed The GO was Full Forward And the Stop Was Back Toward Me , I pulled the engine cord heaps of time sand I saw the fuel leaking. I took the carb off and apart and it looked fine . I put it back together , and my wife said try the motor control half way in case the ON is toward me . I did and it started . I said to myself well DASH. ONE MUST HAVE A SENSE OF Humour!!!!

[@brantsmallenginerepairs]

Glad you got your machine back running. Koodos to the wifey for the suggestion. Thanks for sharing your story. Cheers

[@derbychipandwe2899]

Excellent way of teaching, thanks a million for sharing your knowledge.

[@brantsmallenginerepairs]

Appreciate the comments. Thanks for watching. Cheers

[@Joel-McConnell]

Most replacement carbs are so cheap these days I don't even bother with any sort of diagnoses and repair to them as it is often more work than just replacing it anyway. Just replace the old carb with a new one and you are good to go for years to come solving any current and future issues that may arise with the old components inside the old carb in one go.....

[@brantsmallenginerepairs]

This is true but I like to fix oem and not just replace with cheap aftermarket. Sometimes it's not possible but I like trying to fix stuff first. Thanks for watching and taking the time to leave a comment. Cheers

[@acesmoka]

Me too why replace if you can fix it!​@@brantsmallenginerepairs

[@acesmoka]

I have a question what about the gas in the oil how is that issue solved?

[@TingTingalingy]

​@@acesmokathat's usually the rings are bad.

[@TingTingalingy]

​@@brantsmallenginerepairs I was looking up carburator OEM parts and noticed it was not cheap to buy them due to shipping. Repair shops in my area are pretty far gone or far enough away that I'm finding just the trip to them to place an order is no longer worth it. What are your thoughts on things like this? I know you like tinkering though. Do you have a place close by that has these parts in stock?

[@olivermutukudzi7914]

i think i have same problem in my mini

[@brantsmallenginerepairs]

Hopefully the video helps you out. Thanks for watching and taking the time to leave a comment. Cheers

[@billballoo7881]

Those engines are total crap

[@brantsmallenginerepairs]

I agree. My least favorite small engine brand. Thanks for watching and taking the time to leave a comment. Cheers.

[@mariobrissette]

This video was very usefull for me. I have a Ariens lawn mower with a honda GCV160 motor. Its carburator is leaking and the air filter was full of gaz which make it unable to let the air pass through so the motor stall. A simple fix which isn't so simple when you don't know how to fix it. Thanks a lot!

[@brantsmallenginerepairs]

Glad it helped and thanks for taking the time to leave a comment. Cheers

[@robertclifford1423]

I have a mower with the Briggs & Stratton carburetor on the far right in the video. The fuel started pouring out the air filter like you mentioned. Also, I had just replaced that carburetor a couple months ago with an identical new one, as the original the gaskets had worn out. I don't know how, but possibly mowing sideways on a steep incline sideways knocked either that float hinge pin or the needle valve out. It had about a 3/4 a tank of gas when that happened and it just poured out the filter. When I took the bowl off, both the pin for the float and the needle valve fell right out. I put them back in, reinstalled the carburetor and filter, and the mower works perfect again. I guess I just have to be careful mowing sideways like that, it's a very steep incline.

[@brantsmallenginerepairs]

Glad you figured it out and thanks for taking the time to tell everyone about your story. Cheers

[@acer3]

What if fuel leaks out only when the mower is running? I have done everything you have stated. No fuel leaks out when not in use. I took filter off and can see with a flash light the fuel ever so slightly running out when mower is running. On a level surface.

[@brantsmallenginerepairs]

With the mower running, when looking into the throat of the carburetor, you will see the pulses of fuel coming up from the float bowl. This is normal. Are you saying that some of that fuel is leaking out of the carb towards the air filter instead of getting sucked into the engine?

[@acer3]

@brantsmallenginerepairs Yes. Fuel pulses up and down landing on the tube. Some runs down back to the air filter. Almost like there isnt enough suction or to much fuel is comeing out of tube. Do you know what would cause this?

[@brantsmallenginerepairs]

@@acer3 it's not uncommon for some fuel to splash back towards the air filter. Does the fuel drip or run out from the air filter housing when running? Is the mower running fine otherwise?

[@acer3]

@brantsmallenginerepairs mower seems to run fine. Starts fine. It is just a slow run toward the air filter. Only reason I would know is that the air filter is wet and smells like gas after mowing only. Thank you so much for taking time to reply.

[@brantsmallenginerepairs]

@@acer3 like I said, a little splash over towards the filter is most likely normal. If it starts and runs fine I wouldn't worry about it but keep an eye on it. Happy to help. Take care.

[@TomLax]

Is it similar to leaf blower engine?

[@brantsmallenginerepairs]

Not likely. Most leaf blowers are 2 stroke instead of 4 stroke. Cheers

[@johnwride4911]

Great video thanks, easy to understand, I have the issue with a Poulon Pro with the gas coming out via the air filter..and making nasty spots on my lawn. Before I check further I need to rush out and get some parts before shop closes. Would it normally be the float gasket if the float test is fine, or something else. I am not really mechanically inclined, but since retiring I try😀 to save the cost of shop work and it gives me something to do..

[@brantsmallenginerepairs]

If it's coming from the air filter housing, it would have to be the float or even more likely the needle and seat not sealing properly to shut off the fuel. If the bowl gasket was leaking, it would be wet just on the outside of the bowl and not be coming out of the air filter housing. Just make sure also check your oil level and check for a gas odor in the oil. If the level is too high and smells like gas, then change the needle and seat.

[@evelynmahoney3569]

Great explanation of where the excess gas goes. After fiddling with a few things (fuel line connection, adj. carb bolts, ensuring bowl not misaligned, checking bowl gasket & bolt gasket), thought it was resolved. No more fuel leaking out sir cleaner But then hard to start, hydrolocking (? When rope won't pull). Checked oil. Overfull, just like you said. Oil looked thin instead of thick too. Turkey baster'd some out & got it to run. Got a few mowings in. Went thru fuel like crazy. Hard to start everytime. Lots of carb cleaner & swapping out / cleaning the sparkplug. Many times rope wouldn't pull. PITA! But eventually would get going. Rechecked oil. Couldn't believe it was overfull again! It's gotta be the float/needle/seat. If not, it's gonna be tempting not to drop a lit match on it and end the misery. 😮. Thanks for the great vid!

[@brantsmallenginerepairs]

Definitely a needle valve stuck open or not sealing properly.

[@1up1up11]

Very good explenation, just wondering, my carb starts leaking fuel into the air filter after i fill the tank with about a cup, so im guessing the float doesnt go up all the way so the needle doesnt stop the fuel from going into the float area, should i replace the float or the needle?

[@brantsmallenginerepairs]

You can test the float by shaking it and listen to see if you hear any fluid sloshing around. Replace if yes. But I would definitely start with a new needle. Let me know how you make out. Cheers

[@daved.4740]

other than needle and seat, can the float (kohler carb) be adjusted? Mine tends to dip down about 5 % when the carb is hand held upside down

[@daved.4740]

5 degrees

[@brantsmallenginerepairs]

The older cork floats used to be adjustable because they had a metal tab where the needle valve was. These plastic ones are technically not adjustable but you could try to warm up the plastic tab that holds/pushes the head of the needle valve down. Once warm enough, try to bend it slightly. Please be careful not to do this close to anywhere near a fuel source. Hope this helps. Cheers

[@daved.4740]

@@brantsmallenginerepairs thanks, I was fixing the mower for a neighbour ended up buying a carb off Amazon received it yesterday (was even same huayi) results No leaking starts first pull, all good

[@brantsmallenginerepairs]

@@daved.4740 great to hear. Glad you got it sorted out. Cheers

[@Mike-ig2zq]

Excellent explanation. As an infrequent carb pressure tester, I will continue to blow. Thanks for the video.

[@brantsmallenginerepairs]

Thanks. The blow method works just fine. Thanks for watching. Cheers

[@eugeniujosanu279]

Got a new needle , still getting fuel.. I bought a new full carb and can tell the difference by blowing thru them . Good video ...I got another carb for pressure washer , that one releases fuel thru the exhaust.. I have the feelings may be thesame issue (waiting for your answer) . How you usually cleaning them ? Iv hear ultra sonic bath it s an excellent method

[@brantsmallenginerepairs]

Glad I was able to help. If you believe your carb is the problem, replacing it is the easiest fix. Especially since new carbs are typically so cheap these days. I do clean them as well sometimes. Yes I do have an ultrasonic cleaner but you don't need one. I have many carb cleaning videos on my channel. Hope this helps. Cheers

[@eugeniujosanu279]

@@brantsmallenginerepairs you are right with the the carburators beeing cheep ..I'd rether stick with OEM once and fix em instead going with aftermarket...the one for pressure washer I got is a new one , but aftermarket, and the fuel goign big time in the exhaust with the fuel line beeing open and sitting (no start) , after getting started (with bunch of pulling for the fuel to exit the exhaust) will stay maybe 5 min running then it fills up again ... again , new aftermarket carburator , is like playing russian roulette with aftermarket once (not my first rodeo with them). Also, what would be the best method to keep the carb clean on seasonal machines (the once sitting during winter) also talking about bugs goign in (had thos before) not just gumed up or moisture.

[@brantsmallenginerepairs]

@@eugeniujosanu279 I have had pretty good luck with the aftermarket carbs to be honest, although I don't replace a lot. My first choice is always to clean the OEM carb and rebuild it if necessary with new parts. But if given the option, most customers will go the aftermarket route over OEM given the cost is typically like 1/6th. Now for your question, the best advise I give for small engines is use ethanol-free gasoline. This will eliminate 90% of your problems. Also, before you store the equipment, drain the gas from the tank and then start the machine and run the carb dry before storage. If you do this you give the machine the best chance of starting the next season. Hope this helps. Cheers

[@evelynmahoney3569]

I don't know if I missed it or? Inspect the seat for debris, clean w/Q-tip.

[@brantsmallenginerepairs]

Yep, that would be good

[@clarkkent3133]

Thank you for taking to time to explain. This was very helpful.

[@brantsmallenginerepairs]

My pleasure. Hope it helped. Cheers

[@philliphall5198]

Merry Christmas Hoping you’ll are warm and safe

[@brantsmallenginerepairs]

Thank you. Merry Christmas to you also. It's cold up here in Canada but we're used to it. Take care

[@GoD0fDeIVIo]

Such a thorough explanation is rare 💯💯

[@brantsmallenginerepairs]

Thanks for the compliment. Cheers

[@DJLABESTIA503]

This is exactly the video I was looking for thanks a lot sharing this information I have been having a headache because I thought the problem was the carb seals

[@brantsmallenginerepairs]

Glad I was able to help. Thanks for watching. Cheers

[@DJLABESTIA503]

@@brantsmallenginerepairs cheers 🍻

[@buzz9570]

Very good video straight to the point and interesting all the way threw

[@brantsmallenginerepairs]

Glad you liked it. Thanks for watching and taking the time to leave a comment. Cheers

[@paulnavara7127]

Great job on explaining how fuel can leak out the carb!

[@brantsmallenginerepairs]

Glad you liked it. Thanks for watching and taking the time to leave a comment. Cheers

[@georgeriverasr.6298]

Love you dude😊😊😊

[@brantsmallenginerepairs]

Love you too

[@rileyspears8582]

Dude is 100% canadian

[@brantsmallenginerepairs]

As Canadian as maple syrup, poutine and beaver tails eh.

[@awakenotwoke2643]

Eh??

[@philliphall5198]

Clean fuel tank vent also

[@brantsmallenginerepairs]

This is true except the tank is vented through the cap which is pretty hard to clean. But great point. Thanks

[@vincentcorabi978]

Excellent video.

[@brantsmallenginerepairs]

Glad you enjoyed it. Thanks for watching. Cheers

[@SinOne390]

What if you’ve replaced the carb with a brand new one and it’s still leaking down the back of the air filter housing. I have a GXH50 Honda engine. Cheers

[@brantsmallenginerepairs]

It sounds like your needle valve inside the carb is not seating properly or the float is stuck in the down position. Both of these would cause the fuel to not shutoff inside the carb. Both would require you to take the carb off and inspect these 2 possibilities. You did the right thing by changing the carb but sometimes these knockoff carbs come faulty right out of the box. Hope this helps. Let me know how you make out. Cheers

[@bsen9928]

This video explains the problem i'm having with a Coleman cc100x mini bike because the air filter is soaked with gasoline. One of the carburetor on your video is very similar to the coleman mini bike. Thanks for very good information!

[@brantsmallenginerepairs]

Glad it helped! Thanks for watching and taking the time to leave a comment. Cheers

[@abdulmoizbaig4851]

Awesome video

[@brantsmallenginerepairs]

Glad you enjoyed it. Thanks for taking the time to leave a comment. Cheers

[@abdulmoizbaig4851]

Do you have any similar kind of video to show the function of choke?

[@brantsmallenginerepairs]

@@abdulmoizbaig4851 the choke systems work differently for the different engine manufacturers. Here's 2 for a Briggs and Stratton engine: kzbin.info/www/bejne/hHWmkqCkq8d-mac kzbin.info/www/bejne/oZnWdH2BmrZlf68 Here is one for a Kohler: kzbin.info/www/bejne/o6G6on-lZ95rsNU Hope this helps. Cheers

[@philliphall5198]

What I don’t like is no place to put filter or even a cut off valve

[@brantsmallenginerepairs]

I feel you. Just don't make things like they used to.