How The Auto Choke Works On A Briggs And Stratton Lawnmower Engine

I was working on this old Toro lawnmower today and a youtube video opportunity presented itself:
How the Briggs auto choke works
Watch this video if you want to know how the auto choke on the Briggs and Stratton lawnmower engine works. Back in the day some machines had a choke lever, but nowadays it's a primer bubble or the autochoke system. Honda and Kohler have a similar apparatus, I'll do a video on those in the future.
Sometimes if your auto choke mower won't start when it's hot or cold, this could likely be the problem.. This could also be the cause of the dreaded lawnmower starts then dies scenerio.
Craftsman push mower replacing the vane spring
Craftsman mower won’t start
Replace broken or missing vane spring explained

[@johns.5193]

You wouldn't believe how long I searched for a video to describe this apparatus! Fantastic and thank you!

[@machinesnmetal]

I'm really sorry the algorithm difficult to find

[@sesarbela7071]

thank you blessings

[@geyzey]

Fantastic!! Thank you kind sir for sharing!!! I was going mad looking for this answer and lesson. Big time thanks!!

[@thejonfedor]

SO interesting! I just replaced the carburetor in my Briggs with the same engine and did a bunch of searches looking for this exact information. Thanks tons for the compact, detail-oriented explanation - I learned a ton!

[@seymourbutts2010]

2 years later and this video is still Helping ppl. Thank you

[@machinesnmetal]

thanks for the kind words friend.

[@radiofhi]

Thanks for a clear and accurate description of the carb spring/auto choke operation on this engine. It helped me troubleshoot and repair my B&S engine. I'm grateful and once again mowing grass!

[@EJK931]

Goodness! You solved a week long headache for me. My dumbass threaded the control arm THRU the therm arm.... watched your video and within 10 min had it all working right again. God Bless youtube mechanics!

[@igotdeelz]

I pickup a mower like this for free and clearly someone messed with it because the control arm was also passed through the therm arm.

[@ThomasMiller-hy8kl]

It may have been three years ago you put this out but my goodness you have helped me out with my lawnmower today July 27, 2024 excellent tutoring about the lawnmower thank you very much. God bless.

[@machinesnmetal]

Yeah these engines with these auto chokes are really starting to give problems lately now that they are 5 years old.

[@victorbertolina6545]

Had the problem where mower would not start without a bit of gas squirted into the carb. The carb was cleaned and appeared to be working properly but I noticed the choke plate was not closed when the motor was cold. I removed the flywheel cover and found a tiny twig had jammed the auto choke lever in the open position. Upon removal of the twig and reassembly, the engine started normally. Thanks for the video!

[@machinesnmetal]

Same thing happened to this one the other day kzbin.info/www/bejne/gouolWWdjLNneaM

[@davemellon29]

thanks a lot. I just ran into a issue just like this. I just replaced the carb. and still was starting then stopping. while I had cover off I started mower and pulled the choke lever a little and it stayed running. after a few stops and starts it runs no problem. if happens again ill know what the issue is thanks to you. that thermometer lever might be sticking.

[@LawnMowersThingsThatMakeNoise]

One of the best explanations of the auto choke !!!! Thankyou 🙂

[@will_cal91]

I have been searching for something to explain what the heck was wrong with my mower for ever! I went a full season without a dang vane spring! This video just saved me so much money!!!

[@machinesnmetal]

Super!

[@adrisanc]

I found one of these with the bagger 3 houses down, it was ready to be picked up by the garbage man, but I ran over to get it. Took it apart as it looked like they had attempted a repair on it. Went through it and followed this video on how the auto choke worked and found it was not put back correctly. Thank you so much for this informative video!

[@FreemanEdeh]

Excatly the explanation I needed. Also, explaining the 3 different choke systems was helpful, too.

[@machinesnmetal]

thanks friend

[@philang.3859]

Thanks…..my craftsman was very hard to start, thought it was the carb, but the thermostat arm wasn’t moving smoothly, blew it out with air and lubed it with dry graphite spray. Works great now, almost junked it!

[@francescobarioli4978]

Really well done. Understanding how things are supposed to work is the best approach to fix them.

[@cheaphacks2033]

I have been searching high and low for this video! I have this exact model that I purchased used from a young guy who was tinkering with it. It would run but only have 10 pulls starts then it would die. Then 10 more pulls starts and it would run but at a rough idle. After watching this video I can now see the mower is missing the top spring. 🤦🏻‍♂️ thanks for making this video!

[@Phillip-i5q]

I barley started messing with engines and i had lost the spring and couldnt figure out how it was supose to go other than screwing into the carb, thanks for this info video

[@AustinandBuddy]

THANK YOU FOR THIS VIDEO! Got a mower for free and had no idea what this was and cannot find part number anywhere so this really helped!

[@edmundmaher2045]

Excellent vid ...thought this was a governer system up to now . Thanks for correcting me on this.

[@johondarr2530]

Here we are, one year from the date of this video and your still helping people! Thank you so much, saved me hours of research and solved my issue with my mower.

[@tiz444]

Thanks. Just the information I needed for the auto choke device on my mower. Now I can see how it all works together.

[@CA-UA]

Very helpful video. In my case, I took everything apart and found a densely packed mouse nest with the occupant jammed into the far end of the lever by the thermostatic thing. It would move toward full throttle but then back off and sputter when it hit Mr. Mouse.

[@blove43]

I had a hard time restarting once it was hot- I replaced the coil --this video was huge bc I had the arm inside the thermostat….yer video showed me it’s on the outside……hours later . 2 min fix!!! Thanks!!!

[@DS-bi3fz]

this is just enough detail and quick too - I went searching to understand autochoke, found this, have my answer

[@DaveCurtis-b3u]

Thank you so much for posting this video. It was very helpful.

[@WhitBoss]

Absolutely brilliant video! 1000 thanks. I forgot to re-hook that spring with the new carb install.

[@shadovanish7435]

This is an example of what I dislike about modern small engine carburetor control designs; complex & unreliable system that wasn't designed for the "real world", & designed by someone who apparently has no concept of "real world" conditions. The older manual choke operating system seems much more robust & reliable, & easier to fix (usually with only minor cleaning). This "removed from reality" design mentality seems to apply to many modern machines.

[@landshark218]

yes and no, its probably the best mower I’ve ever owned. and it uses a spring, tell me whats so complex about that

[@DKSE123]

These choke systems work just fine , and are easy to repair if they don't

[@PerroSucio]

Having said that, these new machines are made for people who don’t know how to work a choke……oh well…….

[@breakdown2878]

@@PerroSucio seems like a waste of an education system if it can't teach you real world lessons

[@philliphall5198]

Got to sale more high dallor parts

[@donwilliams6076]

Thanks for the info l have a 2009 personal pace,automatic chock I’m going to lube the arm bolt from now on after l clean it because l just had that problem in the beginning of this year Thanks again awesome video

[@rhecb]

Thanks, you saved me. The spring had come off and I had to fish it out of the engine with a retractor. Now I know how to put it back together 🙌🏻

[@paulhellebusch9759]

Thanks a million for the tip on the weighted spring! You made a project that would have been a pain into a 15-minute tweak on a stretched spring.

[@machinesnmetal]

👊

[@waylangoddard7178]

Been working on an MTD mower with auto-choke. After seeing this video, I know what the issue is with my mower and why it won't stay running. The smaller spring that runs front left-to-right is in the wrong location on the arm. Currently has very little tension on it. Thanks! I figured it was something simple.

[@machinesnmetal]

Excellent 👌

[@danieltaylor9761]

Awesome Vid. Bought mower w/ broken intake (ran when I bought it). When I got home, the duct tape fell off & surging started. New intake took a month to get. I started to put the mower together &...What is this black arm (part of the autochoke) and were does it go.....LOL! You saved me. A million thanks for making this video & also explaining the temp control.

[@user-rj3xn3eb5f]

Great ... I have this exact engine and am experiencing starting problems ... this sure helps explain what is going on ... Just bought a replacement carb from Amazon ... guess what ... it doesn't have the auto choke butterfly valve ... too late to return ... only has the throttle valve Will try to clean and replace ... but this video is well done and helps a lot Thanks

[@803mastiff9]

Mechanical solutions are far more interesting and enduring than electronic solutions. The Bell Telephone Step By Step Telephone Switching System is a great example.

[@ArturKSMR]

Thank you! I took my lawnmower apart and could not figure out where it goes until now.

[@davidkrozy3283]

outstanding presentation!!! My sincere thanks!!!!! Full of troubleshooting GOLD. BLESS YOUR SOUL!!!

[@maximanino]

man you've saved my life , i thought i had lost a piece putting the carburetor on lol

[@blisterphish490]

Thank ou so much. I sorted out the fan part myself but could not piece together what the thermostat was. This video cleared up some lingering questions and will hopefully lead to a better running mower. Many thanks.

[@heatherwilhelm9343]

fantastic...after messing with it all day im had to walk away, lol. thx to you i will be at it in the morning :)

[@gdesveaux]

Thanks for this video. My spring fell off of the arm, and I needed to see where it connected.

[@machinesnmetal]

Your welcome 🤗

[@hereiam7701]

Exactly what I needed to see! You saved me from taking out for repair. Thanks so much!!

[@williamsmythe9291]

thank you for your time in teaching us. it really helped out in the issue i had in my mower

[@TruthShouldMatter]

Exactly what I was looking for!

[@wolfgreen162]

Straight and to the point.

[@taffydavenport1965]

You just imparted me with SO MUCH USEFUL INFORMATION. Thank You so very, very much !

[@rickbales1880]

Thanks for this video.Found out where I was going wrong. Won't say, feel stupid enough.

[@MarshallBros]

This is pretty helpful looks exactly the same to the mower I’m tearing apart trying to get the choke to disengage now I just need to get the covers off all around it to get to that lever 😂

[@Mr1forthefun]

Helped me! My spring fell off, now I know what to do thanks!

[@mobmob5944]

Perfect explanation. I came for the spring question but got more knowledge

[@spring1941]

Thank you for solving my auto choke issue.

[@machinesnmetal]

You are the mechanic now!

[@boblombardi9397]

Well done ...So interesting....Thank you

[@robertreese8044]

Thank God u did this I’ve been looking for a video explaining this..thank u sir!!!

[@jeffgagne5482]

Great video! I would only add one thing. You may need to stretch a new spring to get the correct tension, so it closes and opens correctly.

[@clarencemorrissey8035]

Thanks just fixed. My mower, Thanks to you!!!

[@bijanghahramani7887]

Excellent knowledge to learn Auto Choke

[@machinesnmetal]

Thanks!

[@keithr5638]

Great video and explanation. It's frustrating that the manufacturers decide to take away the manual choke and replace it with something much more complex, which introduces many more things that can fail and increases the difficulty in troubleshooting (all in the name of convenience of not having to manually push a choke lever). A case of "don't fix/change it if it's not broke."

[@machinesnmetal]

The manufacturers have no choice, the government's force emissions compliance on them and manual chokes pollute too much. It's the main reason Honda dropped out of the lawnmower game this season.

[@keithr5638]

@@machinesnmetal Thanks for the info. Why am I not surprised.

[@MrMaurytoYou]

Excellent video sir. Showed me exactly what I needed to know to fix my mower.

[@lzh3131]

This is a very good video. Replaced the vane, lost it. I found your video, Crafts push mower replacing vane spring. Maybe, Craftsman mower won’t start: replace broken or missing vane spring explained. I wish you had shown behind the exhaust, the part you mentioned. Overall very informative. Learned something today! 😊

[@machinesnmetal]

You are the mechanic now!

[@lzh3131]

@@machinesnmetalI’ve rebuilt several carbs on different push mowers, & my dad’s riding mower. This is “new” problem! I really like the tutorial & thanks again. I’m checking out your channel.👍

[@fred5149]

Great information and informative..thank you sir

[@machinesnmetal]

My pleasure

[@brianbower7303]

Extremely helpful video. My exact problem at the moment. Thumbs up and subscribed!

[@machinesnmetal]

Glad it helped, you are the mechanic now!

[@paulpelosi7808]

Excellent information!! Thanks so much

[@machinesnmetal]

Glad it was helpful!

[@dartman040]

Thanks for the tip 👍 👍

[@Bada_Bing13]

Thanks for that video. I Picked up an pressure washer with a 14yr old briggs w/auto choke and it didnt look right. I see owner f'ed with it and replaced all the springs in all the wrong spots lol It still had the same briggs plug in it they put in when it was built 😂 and carb was old coagulated gas & Vaseline.

[@randycordes464]

Thank you for the video explaining it

[@machinesnmetal]

Glad it was helpful!

[@mwjii]

Awesome job thank you!

[@kuchb01]

Oh Man! Thank you - my thermostat arm that you talk about was bent. I actually have no idea what I'm doing, I got it apart, but now I'm trying to put it all back together. (fingers-crossed). Cheers... 73 parts left to figure out 😅

[@machinesnmetal]

You are the mechanic now!

[@kuchb01]

@@machinesnmetal Lawnmower Repair kzbin.info/www/bejne/g3epeIekZcp-ptkfeature=shared

[@kuchb01]

@@machinesnmetal thanks again! I had my 8 year old daughter running my camera 😃

[@timmcallister5763]

Just the video I’ve been looking for. Thanks

[@finnharreidsson5862]

That spring was very loose and cause my brand new B&S 450 148cc to sputter all over the place. I tightened it so it was a perfect fit, no tension other than keeping the governor in place properly. Been running like a clock for over 10 years after that. Was not aware it adjusts the choke as well, kinda clever IMO.

[@Mythendor]

Love the Pro-Tips man thanks a bunch!!

[@machinesnmetal]

👊

[@Saurous3098]

Just what I was looking for. ..thanks

[@machinesnmetal]

🙏

[@TankHower]

Thank you somutch for this video it was very helpful

[@Colt3854]

Use to love the old on/off choke switch. This is the new so called improved version. A lot more complicated with more problems. Why i ask.

[@machinesnmetal]

Emissions requirements. California dosent want people running their machines on choke.

[@70ixlr86]

Thank You so much for the great explanation.

[@machinesnmetal]

You are welcome!

[@mickbrown815]

Excellent breakdown and video!! 🙌👏🏻👏🏻👏🏻👍

[@machinesnmetal]

👊

[@mickbrown815]

@@machinesnmetal well I installed the new thermostat and still doesn’t want to get start or stay on? Damn. 😩 any suggestions?

[@dennisrphymurphy7929]

Amazing info. Thank you

[@machinesnmetal]

Glad you enjoyed it!

[@paulpatt5481]

Thanks for the great video . The pivot screw and the air vane are frozed on my mower. Not sure about the thermostat and will need to check it with heat gun. Depending what I find after getting the shround off, I may just change carb and air filter housing to a primer bulb system .

[@machinesnmetal]

It's common for the vane to get tight on its pivot screw. Take apart and buff it put a drop of tri-flow and good for another 5years

[@dalejrfan820002000]

Thanks for the information. 🎉🎉🎉

[@marknagy4779]

Thanks for the video.

[@machinesnmetal]

You bet

[@rebeccaestelle288]

my boys are learning from ya!! Excellent!!

[@aussieas3073]

Thanks mate helped me big time

[@IBEW44]

That's great advice 😊😊

[@machinesnmetal]

Glad it was helpful!

[@egg_ox]

This was exactly what I was looking for

[@daniellang6112]

Neat! I'm buying one with this feature, will clean throughly an lightly lube.

[@machinesnmetal]

It works great when it all works properly!

[@daniellang6112]

I hope so!

[@FOXTERRA888]

Very helpful..thank you 🤌🏼❤️‍🔥

[@Jake-st5mm]

Really good explanation.

[@craigrupar3367]

awesome video saved me a whole lot of trouble. Thanks

[@Dougy_Fresh]

Thank you!

[@danielsteele7544]

Thankyou for this great little video'now I understand.

[@LuisReyes-eh1ex]

Thanks for sharing...outstanding educational, detailed and brief and to the point all at the same time:)

[@machinesnmetal]

Glad you enjoyed it!

[@debwalker4379]

Absolutely Brilliant!!! I did it!!! THANK YOU :)

[@Deb0naire14]

Bro you just saved me!! Thanks for the video

[@Z32orDIe]

Best video ive found. Appreciated.

[@machinesnmetal]

Awesome, thank you!

[@warrensteel9954]

Many thanks for this explanation!

[@michaeleisenbise4278]

Great video. Learned a lot.

[@jgarcia4502]

Nice really helpful, was looking for info about the same part today... 👍

[@paulcoonce2493]

Interesting; thank you

[@machinesnmetal]

Thanks for watching!

[@brucehampton1545]

Nice informative video. Thank you. I'm trying to get a toro started now so hope this helps. I think the auto chokes are junk personally.

[@machinesnmetal]

Auto choke is fantastic when it functions properly. My customers all love theirs.

[@tinkerbear3458]

Thanks for the info brother 🤝

[@SuperMulletguy]

thank you for this. I have same engine on troy bilt pressure washer and now realize I'm missing the autochoke spring and am sitting here wondering why I can adequately choke this thing and start it.

[@toddfreed]

THANK YOU

[@johnhouli3450]

Thank you.

[@machinesnmetal]

You're welcome!