How to fix a string trimmer that won't prime (purge bulb doesn't work / won't fill)
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- Опубликовано: 18 мар 2021
- Hey everyone!
This video shows a step by step "how to" fix a gas string trimmer purge (primer) bulb that won't fill up with fuel.
This fix will work on your weed whacker, gas trimmer, whipper snipper, string line trimmer... whatever you want to call it!!! (provided the carb kit is in good shape).
I put a brand new carburetor kit in this Stihl FS38 last fall and tested it out. Everything worked as it should before I put it away. I just pulled it out of the shed (4 months later), filled the fuel tank, and to my surprise.... the primer purge bulb didn't fill like it was supposed to. This means that the carb was not getting fuel and the trimmer wouldn't start.
Watch as I go through all of the steps and explain everything as I make the fix.
It works great now!
Cheers,
Dave
Thank you for showing us how to fix our line trimmer. Half an hour and she is running perfectly. Thank you from New Zealand the home of Do it yourself
You’re so welcome Judith! Glad I could help!!!
Cheers from new Zealand also.
Remember to always soak your gaskets in petrol to swell them for a more firm seal it's not precisely necessary but it prolongs the life of the gasket
Very helpful video. Good camera work, no wind or extraneous background noise, no annoying music, good and succinct info, everything i needed to understand why the minitiller wasn't priming. Not mine just helping out a friend. we both thank you so much!
RUclipsrs always spray the carburetor with solvent miraculously solves the problem. It never works that way for me.
I know you posted this over 2 years ago, but your video just helped me fix both my line trimmer and tree pole trimmer. Took about 45 minutes combined! Thank you so much for taking the time to explain in simple terms how to take care of this issue.
Hey Bob! This is why I make the videos - it means a lot to hear your kind words.
Thank you for the viideo...really enjoyed it. but just to decrease worry of a pressurized tank. The primer bulb doesnt require pressure in tank. For fun, just try and prime your carb with the gas tank off. You will never have pressure in gas tank unless gas gets hot. Bear with me...here is a long winded explanation of the way the prime mechanism works. . The bulb is a pump. just like a well pump taking water out of a well. Pushing the bulb drives air or gas out the bulb into the longer outlet tube back to top of gas tank.... (not through the fuel filter). It purges at the level of the small black plastic connector at end of long outlet tube. There is a one way check valve in the plastic base under the bulb that prevents air from travelling from outlet tube back into the bulb (bubble). This allows a vacuum in the bubble. This opens up another one way check valve on bubble base to draw air from the top of the carburetor ( carb sits just under the bubble base). This subsequently draws fuel up the fuel filter tube into the side of carbutator. With every push of the bulb, the vacuum is restored and the cycle continues to draw more and more gas throughout the carburetor while pushing more air from the carburator into the bulb. This cycle continues onward until certain chambers of the carburetor become full and then gas stays in the bubble. This all depends on yet another one way valve on the gas inlet tube that doesn't allow gas to flow back into the fuel filter. Just like a water check valve doesn't allow water to flow from a house waterline back into a well. In this system, it keeps the gas inlet tube and subsequently the whole carburetor full of gas. If you have a bulb that doesnt move gas when you press it, then there is a leak or a blockage somewhere that prevents the vacumn from forming. So any leak in any tube or channel or sticking valve or faulty one way check valve or blocked channel will stop the whole process. And the issue could occur at any point from fuel filter, all the way through the carburetor, to the check valve on the air outlet tube. If you have this issue, it's best to soak the carburetor and bulb base (bulb removed) in mixed gas for a day if the carburetor has been sitting empty for a long time. Pray that it's just a leak in the bulb which is the easiest fix. If not, you have a real pain in the A$$ to work through.
Never surrender! A simple bit of junk in one of the passages can make one wish they new tried to fix their carb, but a video like this encourages us to keep trying. Success is a wonderful thing!
It feels so good!
Best video by far!! Thank you for not telling us 30 minutes of unnecessary info.. down to the problem!! Great job
your mentor is happy with your progress Dave! keep up the good work!
Thanks buddy!
I dont mean to be so offtopic but does someone know a tool to get back into an Instagram account..?
I stupidly lost the password. I love any tips you can give me.
@Luka Elliot thanks so much for your reply. I found the site thru google and I'm in the hacking process atm.
Takes a while so I will get back to you later with my results.
@Luka Elliot it worked and I now got access to my account again. I am so happy:D
Thank you so much you saved my account!
@Adan Santiago You are welcome xD
Hey mate,
Best video I have ever used. So easy to follow and fix something I wouldn’t have touched. If you’re ever in Australia I will buy you a beer .
Had this issue happen while using my craftsman string trimmer on Friday. Took the carb apart and blew compress air to clear passages in carb and it fixed the concern. Thanks Dave great video!
It’s a skill that is not going to be around much longer. This video will help someone out years from now if it’s still here.
That’s my hope, Paul! Thanks for the kind words.
Thank you so much for this video! I had tried to start my stihl and had forgotten to pump it first. Then when I pumped it nothing came. So, I came to youtube to find a video like yours and when you explained about releasing pressure from the tank I went and di it and then started pumping. It worked and I was able to cut my grass and didn.t have to go and find a mechanic! Thanks so much
That’s awesome! Glad to have helped!
"Then when I pumped it nothing came"
...hate it when that happens.
We got a weed eater that had not started in 7 yrs running with the help of this video! Thank you.
Awesome! Thanks for stopping by!!!
The primer bulb does not pressurize the fuel tank. It doesn't have enough volume to create much pressure. You can debunk this by starting the trimmer with the fuel cap off and it will run fine.
When the primer bulb is pressed it sucks a small amount of fuel into the carby from the bottom line. Any excess is returned back to the tank via the top fuel line.
If the primer bulb is cracked it will leak fuel and then you have a fire hazard.And no, without fuel in the bulb the carb won't get fuel.So it won't run.
@@larrynew7258 When Kleetus said fuel cap, he was referring to the gas tank cap, not the fuel primer bulb/cap.
Actually mine does pressurize the tank instead of filling my bulb and it is driving me crazy. Its a Walbro WA-229 on a Weed Eater BV2000. It was running great one minute, ran out of gas and then after filling the tank up it wont suck any gas into the purge bulb. After priming it several times and nothing happening inside the bulb I can unscrew the gas cap and hear the pressure come out. If I pump the primer bulb several times and leave the gas cap on and pull the fuel tube off the inlet side gas squirts out because of the pressure in the tank. Tried a new carb kit too and still does same thing.... pulling my hair out!
@@notny41 The primer bulb is far too small to pressurise the fuel tank, it won't happen.
why dont i watch your videos first before i rip stuff apart ...thanks dave
Where is the fun in that?! Thanks Kid!
funny i learned everything how to fix these and lawnmowers from youtube videos i enjoy fixing them it keeps me busy and its fun to see how they work and a sense of saticsfaction or achievment when you bring an old mower to life.
This video just walked me through fixing my Poulan Pro trimmer - I feel like an expert now, thank you!!!
Awesome video! I had the same problem with my 17year old STIHL FS-46C trimmer and I initially thought it was a bad primer bulb or faulty fuel line. After replacing those, I still had very little to no prime. Before buying a replacement carburetor I decided to take the original carburetor apart and clean it out with compressed air and carb cleaner and just like that the primer bulb fills completely and the trimmer starts right up and runs great. Thanks so much!!
Hey! This is great. This is why I make the videos. So happy to help.
thank you. pulling everything apart and cleaning now fills the bulb
Thank you Dave you and donyboy73 are doing a awesome job helping people like myself tackling jobs like this 👍
Cool. I'm gonna be fixing a craftsman trimmer I subscribed I'll keep checking for info. Thanks man
Thank you Dave for the great job in cleaning the carburetor.I'll have to do the same with by my Stihl trimmer FS 311 because I believe the carburator has clogged because it hasn't been used for a year and the the gasoline is old and filthy.Thank you from Umbria in Italy.
Thank you that video was very helpful I appreciate it.there's a lot of videos out there that are too long and don't get to the point right away .you wasted no time getting to the problem thank you excellent video⭐⭐⭐⭐⭐ ,,✌🇺🇸
Thanks for the info. I wasn't aware that the primer bulb actually pressurized the fuel tank,which pushes the fuel up to the carburator,then thru the bulb & the excess returns to the tank.I know that on some 4 stroke small engines.the primer bulb pressurizes the carburator bowl,which in turn forces some fuel into the intake throat. Thank you for this Great video
I can vouch for this video. Replaced the fuel lines, filters and primer bulb on a Husqvarna trimmer but still wouldnt prime afterwards. Came in to see if there was something silly I missed and came back to a bulb full of fuel. Sat in the garage for too long I guess. Just watching the video was enough to fix it! :-)
this taught me nothing about my Milwaukee cordless trimmer but watched anyways lol. Cool videos your doing Dave!
Thanks Korey!!!
Thank you so much for this. I think I'll head out to my garage and see if I can get mine going now
Thats right super Dave!!, its a "purge bulb" ,so glad to hear you recognize it as so!
Yes sir!
Purging air primes the fuel system. Doesn't matter what you call it; they are both correct.
Wow. I'm very impressed and can't wait to try this when I get home! Thank you. I was having the same problem.
I just replaced my bulb and it will only fill if I turn the trimmer upside down...I guess this is the next step...thanks for the vid😊
Great video - quick and easy - especially for a dummy like me. Worked first time!!
Thank you for your time showing this repair. I found you do the videos with Donyboy 73.
Thanks Nancy!!!
Great job my STHIL trimmer started the first time THANK YOU!!
Thanks for helping me figure why my KM55 R was not priming. (Watching from Barbados)
That heled me sort mine out that has been sat for 6 months in the heat. Thank you!
Great video! I'm in the process of working this problem on a Fs 46c. So a big help!
Awesome Bruce! Keep me posted!
Great video start to finish , explaining, picture , all good , didn't try to make a t.v. show out of it and most important to show us that it don't work and the difference he made in making it work , job well done , didn't waste no time at all , VIDEO IS A GREAT EXAPLE !!!! What u-tube is suppose to be about......
Thank you!
Your video and how you explain and show it is nothing short of awesome. I had the exact problem on the same model and followed your instructions and got the same outcome ... it runs again! Thanks again, you had good video work and the explanation was perfect ... not too little, not too much info. I'm subscribed!
Gary! Thanks so much for the kind words. Much appreciated and I’m glad it worked out for you!!!
Saved my day
Many thanks for the informative demo. I had a problem with purge (primer) bulb not filling on my Stihl HS85 hedge trimmer. Slightly different components, but cleaned out the carb with WD40, and now it's working a treat again.
Hey Robert! That’s what it’s all about for me. Glad you got that beast running. 85 series is some of the best Stihl ever made.
Thanks so much for doing this video! This is exactly what I needed for my problem.
Very interesting video, thanks Dave!
Glad you liked it Raynald!
Thankyou same problem and good to see help us to give it a go
Thank you for sharing this! I have same problem with my stihl since brand new
Glad to help
Awesome. I followed your vid and it totally fixed my issue. I have the exact same trimmer. The FS38. This fix works!💪🏾🤘🏾👍🏾
Hey Pyro!!! That is great to hear!!!
Hey thanks! Bought my first 2 stroke engine ever and had no idea how they worked, had the same issue as you and your solution fixed mine as well so thanks for taking the time to upload it.
Hey Geoffrey! So glad I could help. It’s a lot of fun eh?
Thanks for the timely video Dave ! My STIHL leaf blower has the same symptoms. I'll give your advice a whirl. Your channel is really coming along nicely. Always enjoy watching !
Hey SW! Thanks so much. Give it a try and let me know. There’s a few other tricks if not!
Ey Dave, i have the same problem but that litle gasket/diaphragm is not dry. But still cant pump up the fuel.
Pump is okay , fuel hoses are healthy bit cant find the problrm
@@PchelaUbica it could be the internal check valves inside the carb have failed. I would try a replacement aftermarket carb next.
@@DavesSmallEngines i hear some wierd sounds from carb when im pummping. Carb is original walbro wt160b.
Okay i will order replacement from china. :(
Nice and informative video Dave keep on doing them.
Hey Charles! Thank you, I will!
I loved the video and learned a lot. However, my problem was much simpler in that my fuel filter was completely clogged which should’ve been the first thing to check since it doesn’t require taking anything apart. But in any case, thanks for a great video.
Hey Phil! Thanks for the kind words. You’re right - fuel filter first is a great idea!
Watched your Vid and it worked great. I had the same issue, started second pull! Thanks for sharing!
You're welcome!
awesome , detailed diagnosis. Thank you from Canada. I have a KM 55 Kombi - primer bulb will not fill, new carb kit as well. I am going to do the carb cleaner steps right now !
Nice job on the video. I’ll give that a try.
Thank you sir. This worked flawlessly
Great Job Dave! Keep up the great work and videos buddy!!
Thanks Nash!!!
Thank you so much for the video! It was very helpful!
Cheers from Aussie 👍
Nice video all step by step good job man
Thanks Chris!
Your video was very helpful thank you. You explained it very well.
Glad to hear that!
Thank you so much for this. I was able to fix mine with the help of this video.
great job diagnosing .....thumbs up
Thanks Skid! Appreciate the comments. Take care!
Good fix with very good detail and closeups!! Thanks for sharing your knowledge. I’m trying to learn all I can. There are no longer any small engine classes here locally so good videos like this really helps me learn. Thank you Dave!👍
Thanks Michael!!! Stay tuned for more!
Also wonderful clear video Thank you Dave
Thanks alot. I followed your video and mines is back to normal. 👍🏽I have the fs55.
Thanks Dave - excellent video. Off to tackle my FS-91. Cheers, mb from New South Wales, Australia.
Thanks Mark!
Nice job. Thanks for sharing.
Thanks for watching!
Thanks Adna!
Great video... We'll made and everything is explained well.
Thanks, it helped me
Hey Ed! Glad I could help. Thanks for the kind words.
Spot on, good info and explanations , Thank You 😊
Thank you for your help
Thanks for the videos Dave, have a Echo srm 2100 that the primer bulb wasn't working. looks like almost the same carb, followed along with your vid. After cleaning carb, started first pull.
Hey Andrew! That’s what I like to hear!!!! Glad it worked for you, take care.
This had help me a lot was having this same problem I'm going too try it for myself Thanks
Very helpful. Thank you!
Followed your instructions and solved my problem. New subscriber.
Hey Freddie!!! Thats awesome to hear. Thanks for stopping in looking forward to your comments in the future! - Dave
Great vid Dave nice explanation
Thank you!!!!
Very good work.
Thanks.
Solved my annoying problem today cheers from australia
Hey Kerry! Glad to have helped!!! Cheers!
Many thanks, mine now starts and runs well. Liked and subscribed.
Thanks Jeff! That’s great to hear!!!
Great Video man !! Cleared up a lot of questions. Thanks. Keep them coming !
Hey Phillip! Thanks for the kind words. Appreciate it!
The pump bulb being mounted to that plastic block also had a one way valve within the block that can fail also.
Thanks mate, big help 👍
Nice vid Dave. Stihl is great and easy to get parts for.
Hey TC! I appreciate it. Thanks for watching!
awesome , need to take mine apart to clean the carb
You should! Good luck!
Exact same carb on my Stihl garden tiller. Exact same problem too. Now I think I can fix it. Thanks!
That’s awesome Chris! Cheers!
Fixed it. Cleaned out the carb but found that the obstruction was in the primer bulb housing itself. Hit it with carb cleaner, reassembled it, and it fired right up.
Great video Dave well done
Thanks Henry!
That my friend is just what the doctor ordered! 100% my problem and the fix. No messin' around followed Dave's instructions and I'm good to go!! Thanks Dave. Now you just need to post carb dissasembly / clean up for a Honda lawn mower. Stay safe!!
Hey Kmac! That’s great to hear!!! Thanks for watching and stay tuned for more!
@@DavesSmallEngines you saved me $$. So in turn, I’d like to pay you back with a rifle sling if / when you find yourself in the market. www.slytactical.com. You can youtube us as well. Let me know. 👍
@@kmac556 Wow! what an offer!
I’d love one for the new 10/22 I just picked up!
@@DavesSmallEngines check out the site and tell me what yoi want. Just need your height and whether or not your right or left handed. Send me an email
- Kmac556@pacbell.net
@@kmac556 sent!
I can’t believe i have the same stihi, same problem even ran ok last summer. I dismantled cleaned and blew it out. Wouldn’t pump fuel. Have coffee with youtube search. Yours came up 1st. Nah doubt it but I’ll try the carb cleaner.
Yes, worked like a charm first pull.
Moe!!! That’s what it’s all about for me. So glad to have helped. Take care!
Love the video you make real simple to work on this small engine congrats my friend ernie from Miami
Glad you enjoyed it
After some more research & a couple of hands-on experiences,I learned that the primer bulb does NOT pressurize the fuel tank..In fact most tanks are vented.The bulb actually sucks air,to start with ,then sucks the fuel with air,until the system is full,then it just pumps fuel & returns it back to the tank.Now the system is primed & the engine is ready to start.
Yes - I have learned that since too. My mistake.
Thank you so much.
Great video and description!
Thank you! Perfect!
Thanks Jim!
Great video. Learned a lot.
Got mine running! Much thanks!!
Great to hear!
thanks for video
Thank you, this video was all I needed.
You’re very welcome! Thanks for stopping by
When bench testing try hooking up a hose to pump fuel from a able top container so that you don’t reinstall to find that you then are removing it again and again.
Thanks. Going to try this. Wish me luck.
Let me know how it goes! Good luck!
@@DavesSmallEngines Nope did not work. Maybe just buy new carb on amazon? Comes with new fuel filter. Plug. Extras for 22.98. Thoughts?
@@bufferzone3247 sounds like a good next step!
@@DavesSmallEngines thanks
Awesome video,stay safe
Nice vid Dave - after changing out the gaskets & diaphragms ensuring each were in the right order as both pump and inlet are different. I still couldn't fill the purge bulb even after spraying things clear as you did. So swapped out the lever for the inlet valve and the diaphragm for the pump and BOOM she starts everytime. I knew it would be the inlet valve as my symptoms were starts first time only and runs well after a quick carb and plug clean. If it puckers out due to no gas its hard to get it going again. I suspect the new diaphragm is too stiff or not reaching the lever to lift the inlet valve. The gap on the lever and carb casing is so small that you'd think its high enough to get pressed by the diaphragm. I know at some stage it aint gonna pump gas thru one day. Might let the diaphragm soak for a week - see if it softens up. Hehehe anotha DIY KIWI from NZ.
Great job 👍
Thanks Dan!
Good class
This cleared up a few things for me too, thanks for the great video!
Excellent video, nice job. Fixed my Stihl HL 45 hedge trimmer using your video. It primes, starts, and idles now. I'm with Ethan (below), on some "fine tuning" help. Mine runs good but bogs a bit on acceleration, and I can't seem to "fine tune" it to get rid of the bog.
Sounds like it could be a bit rich on the H needle.