Carb leaking fuel? Here's how to diagnose the problem...
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- Опубликовано: 8 фев 2017
- Carburetors may now be considered 'old school' but they have been doing their job for a very, very long time. Meaning that despite them been replaced by fuel injection on pretty much all cars and most motorcycles now, there are still millions of them still out there providing our engines just the right amount of petrol and air to make us smile every time we open the throttle...
'Carbs' as they are known do have their problems and dribbling out petrol from their overflow pipe is a common issue, especially if the engine hasn't been started for a while & the carb is a few years old.
So...after many requests, mainly from my students, here's a video covering how to diagnose why your carb is leaking fuel & no, I very much doubt it's the float height that's wrong so leave that alone...please!!
If you have any questions then please add them to the comments section below & I'll get back to you just as soon as I can.
Andy Mechanic 
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You are the first ive found with a legit solution instead of saying just get a new carb.
i dont even have an atv but this video is the one that i need. thank you so much.
Well done Andy. Shows you can learn every day. I am 75 years old! Thanks mate. Peely
Lifting the float by hand to check if the valve is leaking is such a brilliant move
Or you could simply blow down the pipe... If air can escape so can fuel
Thank you so much, as an old retired Army instructor you’re spot on. A life goal is to rebuild my 1993 KLX 650, you’ve got me headed in the right direction. Cheers!
Thanks Jason, appreciate your feedback. Good luck with the rebuild.
Cheers Andy
honestly this is the best video I've seen, thank you!!
Thank you for making this video. Prior to watching this, I had searched and searched to find what was causing my leaky carb. I followed the directions of all the other videos out there and only replaced the needle valve... still leaked! I knew nothing of this o-ring problem until your video. Fixed the problem and saved so much frustration. Just for context, I have used youtube to teach me many many DIY things over the years, yet this is the first time I have ever left a comment... hopefully that demonstrates my level of gratitude... thank you for taking the time to teach the rest of us.
Outstanding video. This gentleman has superb knowledge of his trade and has the ability to explain problems with carburators and how to repair them with precise and concise explanations. Thank you for your time sir.
Same here
This video is awesome, and you're a great teacher!
This helped me resolve why my generator had a leaking carb!
Thank you for the video, and mechanical education!
Your video was by far the most helpful, Thanks for taking the time to explain in detail how you solved the problem.
Best simple carburetor diagnostic video I have seen. Thanks for the knowledge. Fixed my Kawasaki 500 with this.
Fantastic tutorial; thank you. Helped me on several different levels. Thanks again,
2003 Yamaha 660 Grizzly
Great Video !!! Very thorough and Andy knows what he is talking about. I like his calm and pleasant way of explaining whats wrong. Cheers !!!!
Andy thanks for your diagnosis trouble shoot carb issues, very helpful glad you enjoy what you do.
Thanks Mr! Was having this exact problem with my 98 Yamaha Grizzly 600 carb. You're a good teacher & mechanic for sure! Cheers
I just rebuilt my 2006 Honda CRF250R carburator and there was 1 extra O-ring that none of the other youtube videos mentioned in their walk throughs. Now the carb is leaking gas out of the vent. Looks like I now know where that O-ring was supposed to go. Now to tear that bike apart again. I wish it wasn't such a PITA to get to the carb in this bike. This will be the 3rd go around with this bike. Thankyou for the thorough video. Smart man!
Fixed my carburetor 5 minutes after watching this. You are amazind dude, thank you soooo much
Hey I just wanted to say thank you very very much for taking the time to make these videos! You are very good at teaching and very talented mechanic! You helped my son and I fix his bike! I’m very great full for this video!
I think it is halarious that your bench mat says ( get organized) 😂😂😂
Right after you mention the positive effect of being organized.
Love how you even film the issues.
You are always my first choice in learning anything for my 4 wheelers/ side by sides.
THANKS
Haha! That wasn't planned! Funny though!
No problem at all, it's great to know the videos are helpful to so many people around the World - that's exactly why I do it :-)
Appreciate your feedback, lots more videos to come. Cheers Andy
very analytical! thank you Andy! 5 years after the first release of this video and its a masterclass!
My dr 125 sat outside for 4 years and thanks to this video i knew how to diagnose my carb that has been leaking for a week now. This video is the.l best vid i found
Thanks Liam :-) appreciate your feedback & great job fixing that leaking carb. Cheers Andy
Great video. Very helpfull on my hardtail custom with a 100ci revtech. It's got a mikuni hsr42 carb and this fixed the issue with the o-ring on the float needle brass housing. Thanks.
Just found your channel
You have given me the confidence to have a go at my wife's XT225 which is a pig to start
Love your calm way of working
Thanks
Appreciate the information!! I'm so happy that I've found you and will certainly need and use your knowledge base in the future. Keep em' running Andy!! Thank You. :D
Qq
Wow! This video was awesome. I was looking for information on why my 2hp outboard was leaking fuel when I opened the valve and came across your video. Now I think I have enough information to tackle this on my own instead of taking to my local repair shop. Fingers crossed!
Wow! Brilliant video !! Found it really helpful... I have a leaking carb of my eurorider 50cc v-sport scooter...I'm gonna definitely have a crack at it!! Awesome Andy...
how have more people not watched this. this literally is so helpful. well done mate good one
Awesome tips I've not seen elsewhere. Solved my Honda mc quad carb problem while on the bench, not after re-installng on the bike and finding the problem not fixed. Thanks!
Thought I would have had to skip a bunch to get to useful information. Was pleasantly surprised to find great troubleshooting ideas and a much broader understanding of carb fuel intake.
What steikes me is that you take the time to do intermediate small tests, to progress, in small but certain eliminating steps....that is great info! You are a good mechanic, great teacher, i subscribed, thanks Andy! Everyone should understand carburettors, they are everywhere🤩🚣♀️🇧🇪Belgium greets you!
I have a little honda rebel 250 leaking so much fuel. Now i feel confident in diagnosing the problem on the inside. Thank you so much!
Rather clever way to troubleshoot. Thank you for sharing your knowledge.
This video was awesome I have a 2005 Polaris predator 500 and my fuel is leaking in that exact location I tried rebuilding my carburetor completely and still leaked never would have known that there is a rubber seal there or adjusting the level of the overflow tube 5 ⭐ sir
Excellent video, I’ve been working on carbs for years and always come to RUclips from time to time and just came across this. Great job on explaining, demonstrating and entertaining!!!!
And I forgot to add the most important part lol. Spot on what the problem was with a carb I’ve been having problems with..Thanks a Million
Just like all the other comments you saved me with this video. Nothing else like it out there. I greatly appreciate it. And you gave me some carb tips for a lifetime.
hi v. Hhu
Just want to say thanks! This video taught me a heck of a lot. Hope you realize how many people you're teaching.
+thelippy Hey, many thanks for the feedback. It's great to know my videos help people all around the World. Lots more videos to come too :-)
Looked all over the web and didn't find the answers I was looking for. The verification methods you used to determine if it was working before re-installing were spot on. That was what I was missing. Had this carb on and off the quad a dozen times and not once was it any better until I saw your approach. Previously... every time I re-installed the carb the fuel ran right through the overflow tube time and time again. I will take these lessons learned and apply to all my carb issues in the future with complete confidence!!!
Thanks Sid, pleased to be of help. All the best. Andy
Wow, this is exactly the issue I just had after rebuilding the carburetor on a Yamaha TTR230. I didn't replace the float seat because it was too tight with the new o-ring. Your little trick of putting a bit of grease on the o-ring worked great! Put it all back together with the new one and there are no leaks and the bike runs great! Thanks so much for the lessons! ATB!
Hello.. Thanx for making this video.. My dad's tw carb drips a puddle on the garage floor overnoght.. Sure enough got a perished o ring around the seat...only after watching your video I realise this.. That gosh dang seat drops in super loose.. Thanx for your good lesson in this video I now know the proper way to diagnose a leaky carb step by step.
Good video mate. I have literally stripped and cleaned the whole carb/filter changed spark plug/fuel. Nothing come across this video and knew straight away that was the problem.
Sum1 should give you an Oscar award for this video. It was exactly what my issue was. Thank you
Thank you so much brother. I really appreciate your time, and knowledge. It is truly a blessing...
This is the perfect video I needed, my cbr600 f2 is dumping gas from the carburetor... I'm going to run this checks on it for sure 🙏
Thank you for posting this video, I thought I knew a lot about carbs but didn't know about that o ring prob, I have been trying everything to stop the leak taking carb on and off half a dozen times and now it is sorted thanks to you, wish I had seen your video sooner, you are added to bookmarks.
Thanks Anthony, great to know it's all fixed now :-) Cheers Andy
Been a CAT tech for 20 years. Your videos are very watchable. Facts short understandable easy.
Thanks for good videos in the right tempo. Ready again for a second atempt with carb on my GN 250 after 7 years hidden in the garage. Aarhus, Denmark.
Hi Andy, thanx 4 your video it help me a lot. my Motomia Spitzer has been parked 4 over a year and today i decided to fix the starter to ride it again and as my luck is, the feul was streaming out of the carb. So thanx to your video I am able to fix that myself.
Man you're the most Rogers of mechanics!
I'ma a proud sub, keep up the good work!
Thank you for this video. I was pulling my hair out on this leak and didn't even think to check the o-ring.
Great video. Easy to follow and replicate to diagnose the fault. Thank you
just what i needed to see tonight to fix my carby, thanks mate was extremely informative!
Great video, super informative and great job explaining everything in a way a non mechanic can understand.
Great video! I fixed my Honda’s leaky carb, though it wasn’t the same carb you got me to take mine apart and do the repair. Thank you.
Thank you Sir for making this video. You saved me from buying a new carburetor out of frustration
Exactly what was wrong with my carb. Needle valve seat o ring bad. I diagnosed it from your vid. Thank you!
O-ring was cracked and shrunk on my CR250… fround a perfect fit off of a wacky ring for fishing, great video thanks!! would of never been able to fix it without this video
Thanks for the information Andy
You are my hero! With your video I think I found the issue with mine.
Thank you for a great concise video Andy! We have a bike with a leaking carb. 1 of 4 carbs on it will not stop leaking and this rubber seal is the only thing we have not checked. Absolutely brilliant. Keep up the good work. All the best from Haggis Motorcycle Tours over in Bonnie Scotland
No problem....Good Luck sorting the leak. Great to know the videos are helpful. Ride safe. Andy
Andy, you're a legend. This was the exact problem with my Jinke PZ22 carby on a Lifan 125cc engine Quad Bike. It had horribly contaminated fuel when I got it from an auction, but oddly, not leaking. Carefully dismantled the bowl to remove contamination (the top "half" of the decanted fuel was deep brown!), cleaned and reassembled, only to find it started leaking from the overflow. Pulled it apart again, checked my work, no mistakes, all good, and it still leaked from the overflow! Aha! Armed with your information went back to the carby, pulled it apart and sure enough, the o-ring was blown. Thanks for the info!
So how come it wasn’t leaking to begin with?
Mate, you have been a life saver for me, I rebuild my Mikuni carb as I have done 1000 times but this time I could not understand why the carb kept overflowing. Checked the float 10 times and it was set perfect. Turns out to be the plate that holds the barrel that holds the needle was not tighten enough to set the barrel's o-ring and seal properly. It was not until I seen your vid that it hit me, something so simple can cause a migraine headache. When you lifted the float with the fuel on it was an awakening moment for me. Again, thanks for your vid, thumbs up.
Hey, no problem at all, I'm pleased you found the video helpful & got the problem sorted.
Thanks for the feedback & keep safe. Cheers Andy
@@AndyMechanic Another question I need to ask you, does the pilot jet needs to be screwed in all the way until it seats or does it need to be turned back a few turns? I cant seem to find the settings for this carb. The pilot jet is the only one I did not note the amount of turns from factory, I removed the old one and replaced it with a new one but failed to note the amount of turns, your input will be appreciated. Thanks.
Hi, no problem. The pilot or idle circuit jet it screwed in all the way until it seats. The pilot screw however is specific in its position as it adjusts the mixture at idle. If it's the idle screw you are referring to then usually it's position is between 1 & 2 turns out from after seated, however this is specific to vehicle - service manual will have this info.
Hope this is of help
Cheers Andy
Thank you for making this video very informative my scooter is constantly leaking from the overflow bowl I will check it when the weather is nice here in D.C.
Great video with awesome insight, I’m working on a mower carb and it gucked up and I have great knowledge on how to fix it
Great video! After taking my bike and carb apart 4 different times to change the main jet, each time I reassembled it leaked out the overflow
Hose a lot !!! couldn’t suss it out and was getting frustrated... you helped all the way from New Zealand!!!! the culprit was my valve seat o ring,, thanks for this! Easy to understand and a solid way to troubleshoot and find the reason a carburetor is leaking.... Huge thanks !!!! Cheers,,, from Maryland!! Braaaaaaapppppppp!!!!!!!
No problem Jaque, ride safe! Cheers Andy
Kazuma Rage 110cc now runs fine! Thanks Andy for this video.
I got the ATV working properly by having the blocked primary jet cleaned by a local dealer - they have a special set of super-fine file tools to clean the jet.
The poor start and poor idle are now gone.
I have fitted a bike fuel filter (it's tiny) in the fuel line and will put additive in the fuel before wintering the bike in the garage.
Cheers again Andy & keep up the good work !
+Alex Lintern Cheers Alex, good job :-)
70i>67
Brilliant! Thanks mate! Watching you from the Philippines.
This was exactly my problem and I fixed it. Thank you!
Thanks for this video I feel confident to DIY my self keep up the good content
Brilliant video, and everything explained to a T, ill be taking the carb off my quad tomorrow because it has sat for a year, and fuel is leaking out the overflow pipe. Great thanks
My quad still won’t start, still no spark, though if I put the spark plug in my bike it sparks ok, I’ve replaced the cdi, the coil, and a few other bits, but nothing, the flywheel won’t spin either when starter button pressed, starter is spinning though, any ideas????
Engine siezed or starter Sprag clutch has failed
thank you for your testing tips! Ill be using them today on a yamaha 350 big bear. great video!
Always good to amass a collection of O-Rings! If you wanna go properly bonkers, start collecting them in various materials (Nitrile, EPDM, etc...) to save the day in any application. :D
I love carburetors. Such amazingly simple little things that're so capable for what they are. I recently took a job with a company that does repairs of lawn, garden and construction equipment. A bit of a shift from the automotive world that I'm used to, but so much of the knowledge carries over. I think there's a lot of real-world value in teaching the operation and troubleshooting of carburetors in trade schools. :)
Great video and knowledge. Thank you very much I have learned a lot from your video. Now will try to fix my carb :)
Good Luck, hoping you find the problem :-)
Cheers Andy
Great video Andy thanks - that o-ring is almost certainly the problem causing the same symptoms on my '03 Yamaha TT600R. Bits sourced!
+Philip Smith Cheers Philip, let me know how you get on. Cheers for the feedback. Andy
This video saves me from going to die!i fit new gasket and it leaks ! When i see this video i fix it !ttr 250 keep it up !!!
Very informative on the workings and repair of a carburetor++++++
Awesome man, thank you very much for your video 👊. It explained everything perfectly.
Great video - thanks. I have a leaking carb on my YZ125 and I am going to try these steps to cure it.
Excellent job. Thanks for the video. Brilliant!
Excellent information and great video
Thank you for sharing
Very good video with great explanation! Thank you 👍
im glad i watched until the end, where you covered the issue of spline alignment
Excellent video Andy. At the end you mentioned the crank case full of petrol. That’s the problem I have. But it’s on my pressure washer. I presume it’s the same process. A long video that some will not like, me I enjoy that. Learned a lot from this. Thank You 🙏
P.S. SUBBED.
Thanks for your teaching videos!
Brilliant! Thanks for this video! I'm a fan.
You make great videos. Good explanations and good visual demonstration.
Thanks Daniel :-)
Good video and spot on because I have already done this. Had trouble getting the "o" seal in but a bit of vaseline does did the trick.
I had this issue with my dads old 80s Suzuki dr 250 helped me out a lot thanks 🙏
Having problems with fuel in air box replaced fuel pump still happening.think it's draining from tank throu carbon tank to air box
U are the man, very informative video. Thanks
Very detailed! Thank you Sir!
Ok, so I know this video is old but so is my bike! I have a 1986 Yamaha SRX600. You should appreciate this since you're a Yamaha mechanic. This is kick start only. My problem occurred about a month ago. I wasn't paying attention and overfilled the tank. It took a few kicks to start but she started up and I rode 3 miles home. Of course, it was getting rid of fuel out the tank overflow during the ride. I figured, oh well, no harm.
Next day I go to kick start it and it was not even trying. I felt like the kick was just turning over the cylinder. As you know, if a kick start bike didn't start in a few kicks you can wear yourself out quickly.
I tried and tried and tried over the last few weeks. Even open the gas cap, etc... I had about given up and all of a sudden she kicked over so easy it freaked me out. I let it run for a minute or so. It idled perfectly, never needing choke to keep it alive or anything which also freaked me out because it started and idled perfectly at 1,200rpm right from the get go. Usually I have to twist the throttle to start it up and then apply choke and ease off the throttle.
Well, I turned the bike off thinking WTF it's fixed itself! I turned the bike off to lock the gas cap on and proceeded to kick start the bike and bluh... . Bluh.... Bluh... Once again she doesn't even attempt to start. Now, I know I'm getting fuel, I know I'm getting spark (even installed a new plug... Old one was not wet), I know the coil is good and the CDI is good or it won't run. I mean, it has to be a fueling issue. I'm about to pull the tank and replace all the fuel lines but somehow I think it's carb related.... It's not leaking fuel.
Your thoughts?
Thanks Andy last guy spoke different language...so no idea..
But love your explanation...
Thought mine could be o
Ring as well Suzuki 1200 SS
4 carbs ,1 leaks horribly
Cheers Mal
Best video I have seen on this type of problem. I believe you may have fixed my Yamaha quad. I have subscribed. Cheers from Canada.
First video of yours, I have watch just amazing how much detail you go into. Obviously subscribed right away👍
great explaining and visuals! thanks
this is the vid ive been looking for.
thanks mate
You sir are a saint! Thank you for the video
6:30 a.m. a year later. Still fascinating. Just a comment on that grease you were using when trying to squish that oversize o-ring on, just in case s.o. doesn't know -- it's red rubber grease which is safe for grease.
What I thought was a dilemma: for garden machinery, which is not used over winter, we're told to turn off the fuel, run the motor 'til it runs out of fuel, emptying the carb so there is no build-up of crud. Here, the problem was that the rubber went dry because of lack of fuel so presumably the carb on these engines should never be empty.... But if you're not riding over winter and having a regular flow-through of fresh fuel, you'll have to put in an additive.
I'll come back and watch this again in a year's time.
Excellent! Who'd have thought that a lesson on O-ring dimensions would be interesting?? But it was, and my interest in O-ring dimensions has grown to the size of a T-shirt.
I'm here for what you did at 40min. Although the needle passed a pressure test, I wanted to see something more convincing: if I could put the bowl back on, and let petrol in, if the needle was seating properly, there would be no leak. But I wanted another opinion. And you have it! Thanks a lot. It's nice to do the pressure test -- which itself is better than just blowing into the fuel spigot (?) when the carb is inverted -- but the most convincing is having no leak from the float bowl!!
Eureka!!! Finally found the fault with my carb, thanks to you!!
Great job :-)
Thanks for the video brother. BIG help!
I really enjoy your video today my name is Raymond from Ghana I am riding on Kawasaki El 252 I am facing an overflow problem I'm going to try your teaching the results I will come back to you
Great video and excellent detailed explanations ... loved the bit about the O ring measurements and how you overcame it. My newly acquired 98' Husky is draining fuel from it's vent and I was looking for float height stuff on YT. The last owner said he had recently rebuilt the carby and he had since had issues ... with the information you've shared I'll be better prepared when I go looking for the problem - Thank you Andy.
Cheers Mal, pleased you found the video helpful. It's rare it's float height so only adjust if you are really sure it's out of spec
Cheers Andy
@@AndyMechanic Thanks Andy, I just had a look a look at your channel to see if you had a video about float height .... but kinda got stuck with the tool girls instead ahem. Did you ever make one on float height? I understand that if it's too high [fuel] it can make your bike run lean and too low rich or vice versa due to mixture. Be interesting to see your take on it as the way you deliver information is brilliant, and NO I wont be adjusting the float height on my bike unless its the absolute last resort and the bike is a TE610 so I have no need to mess with the carby to go faster just last longer :-)
Cheers. I'm preparing a video on float hight adjustment. However, the method of measurement varies greatly between manufacturers so it's not that straight forward unfortunately.
Cheers Andy
@@AndyMechanic Well it turned out to be the float height, or specifically the brass rocking lever that controls the floats. The Dellorto PHM on my bike has independent floats. If you lay your hand flat on the table and raise one finger that's what the rocking lever looked like [approx 3mm difference]. I straightened out the lever and measured both were equally parallell to the body [per spec'] and all good. Needless to add the air mixture was way out and backfiring flames on decel', idle would increase then slow down and then die, hard to start etc. I've got it leaned out now with the occasional backfire amd stable idle so more to do there. I live in a studio so my bike is at friends place where I can work on it but it's only 1 day per week [50km away]. Anywho please forgive the punctuation I just thought it weird that the guy I bought it off left it like that and I dont ever remember having float height issue on my bikes in the past ... then again I'm no engineering mechanical genius. Love your work Andy :-)
Cheers Mal, pleased you got it sorted & thanks for taking the time to let me know what the issue was. Ride Safe :-)