Stihl FS 55RC trimmer won't start fix 

A handy tool to have for testing these carbs is an air pump with pressure gauge. Connect to the fuel inlet, pump to .5 bar and it should hold pressure. If it doesn't, the cover gaskets are leaking, or the inlet needle is not seating. If it holds pressure, pump the primer bulb till pressure gauge reads 0 and keep pumping till it pulls a vacuum. It should hold a slight vacuum for at least one second. If it doesn't, the primers check valve is defective, and carb should be replaced. If it holds vacuum, connect the air pump to the primers output nipple and pump primer till gauge reads .5 bar. If primer won't build pressure, again its a defective check valve and carb should be replaced. This is known as the 3-step test. The problem with the cheap knock-off carbs is that these motors will often use many different versions of a carb for a given model. In the case of the FS55, I think they used about 12 different versions of that carb, with the carb being changed each time a slight change is made to the motor design. Its best to try to get the right version of the carb for your motor. Theres a black number stamped on the carb that begins with letter S, such as S34, S55, S62, etc., which indicates which version you have. I recommend using the orginal Sthl carb for best results. Great video, by the way. Brian / Stihl tech

I would have remove the carb the first time and either put it in my ultrasonic or put it in a small pot with dawn dish soap and boiled it for a while. Then installed a complete repair kit in the carb. Put back on the trimmer only to see it still won't run. Then lay on the ground and kick my feet in a temper tantrum. etc.

This is a brilliant video. Followed the instructions to add small amount of fuel directly to the throat and it worked! Thank you.

Thanks. I had new carb installed last year and I couldnt start trimmer this year. I followed your tip with fuel and it started. Then I cleaned fuel pump button and everything started working.👍

Phenomenal channel my friend. I do small engine repair for work and find your videos really relaxing and interesting to watch.

I would have attempted one cleaning, at least before buying a new carburetor. Love your videos, man!

Thank you for cleaning.Many year ago i used to go to a Sears repair shop,and they washed all the units before they would service it for $ 5 and was a must.

I think your approach is spot on. In my experience most people are quick to jettison a carburetor when basic repair would do the job. Your approach is excellent. Btw, you have a good "speaking " voice for videos. No "ahs" or "umms". You're missing your calling. . VOICE over work.

I always put a complete re-build kit in when I have it apart the first time after using my ultra sonic cleaner or flush all passages with carb spray. I had a customer that wanted his riding mower cleaned after I tuned it up and changed the oil, but he did not want to pay the extra hour to do it, so now I always ask if they want to pay for the additional cleaning. Thanks for the great video's.

For only $10 and one-day shipping, I would have definitely gone with the replacement carb like you did. Best part is, it worked perfectly the first start!

A big thank you to you for showing me how to fix my trimmer I follow your instructions in this video and Voila. It worked.

Thank you for simple explanations that are complimented by the GREAT CAMERA WORK!!

I would definitely try my best and clean it, buying new part for me is almost always a last resort. Keep it up 😁👍

Really enjoy your videos!! You do a GREAT job of explaining in detail each step of the process!! Thank you!

I've done both. I have a friend trimmer that is the same brand as this one. I ordered a carb kit with extras for his trimmer. I paid $13 for everything. I didn't ask him and I doing for free.

Those trimmers are great. I have a Stihl fs55r trimmer. I had the same problem with the primer bulb, where it didn't prime. This was because my primer bulb base was bad. Its the black plastic part. My local dealer wanted 30 dollars Canadian for just the plastic piece. So i decided to go with a brand new oem carb from stihl. Best part was, it was only 65 Canadian. With the Canadian dollar being so low. It would be like 30 bucks for a new oem carb in america. and it solved all my issues. the trimmer runs like new now.

Great video! Clear and easy to understand. Thanks!

You did the obvious right thing, in my book. Easy plug and play fix.

I bought a Lawnstar blower recently, and had all sorts of carb problems from the very 1st day, took it back and they put a new carb on it, and bingo, its a different machine now! 🙂 👍🏻 🙏🏻

the video I needed for my FS55. thanks a lot dude, straight to the point with all the infos. Cheers from France ! :D

Thank you for the hard work and keep up the good videos

Not sure I would have known enough to remove the plastic to get to the trigger. Bending it was the best decision for this machine. It's almost ready for the parts bin anyway. Thanks for sharing.

On the first prime, I seen it was because of the small for the top of the diaphragm. Fuel flows through there. I'm sure if you poked a hole there, it would have worked. That old carb may still be good

I found one of these on the side of the road last week. Sprayed some cleaner in it and it started up first pull but the carb primer will not inflate. New carb kit arrived yesterday. Maybe I'll get to it today. It has the edge attachment but I am going to covert it to a trimmer with one of the many trimmers I have laying around.

Dette er på mange måter forbilledlig utført. En instruktiv, klargjørende og meget god video. Tusen takk! :) This is in many ways exemplary. An instructive, clarifying and very good video. Thank you very much! :)

Excellent close up shots , thanks .

After watching the vid I'd buy a new carb. Thx 4 the vid. It really helped. Back to that stinking W E.

Like you said, check with the customer about OEM parts then make the appropriate repair. I use mostly off brands for myself and at ten dollars it's cheaper to replace than play with it. I usually check my used supply first as I save them and I will rebuild some for these situations. I also sell them on occasion, if I have enough in stock, this pays for rebuild kits. I haven't had any complaints so far.

hi there ... great video.. Just wanted to comment that it would be handy to have kinks to the replacement carb ... and also - perhaps ... when replacing parts inside the carb for example - have details of how the parts refit. Overal -I liked the video. Very informative and you have a great manner to your approach. Thanks for the video. Very helpful.

I didn't know the carbs were so cheap. Man what an easy fix just get another carb!

The problem is the diaphragm it hasn't god the hole for the primer bulb on the side like the old one so there is no chance of getting fuel in it. Had the same problem on an FS 45 even though the seller of the rebuild kit mentioned it in the description

Thank you very much for this. Ive replaced the few bits bar the carb. Gave it a look today but i need a new one id say. Keep up the good work

Mine is a outdoor left in the elements tool, so it gets wet and rained on and baked, it was free. And I've used it for 10 years and I've cleaned it every so often so you wouldn't know it was kept outside lol. It has alot of blow by on start up, cause I don't use it often. But then it clears up after half a second.

One of the best videos I have seen when fixing a tool, great explain and did it slow enough to comprehend the lesson. Is the KM55r is the same motor as this one or is it different? Love this video

great video, good details and explanations of each part step by step. youve earned my sub sir.

I'm the type of person who would have bought a real stihl carb. I don't mind using the generic Amazon carbs, but I spent so much on my stihl tools that o only use their parts. Great videos! I have that exact trimmer.

Just a great video . Thanks for upload

Thanks for cleaning ... I’m one of those viewers.

Great job!! very informative!!

Another great video thank you buddy

I definitely go for the cheap carbs anymore...so much easier than cleaning & rebuilding. As I'm sure you know, sometimes they still don't run right.

Thank u so much for helping me to fixing old dad mower

Since the "knock off " carburetors are so inexpensive I probably just replace the carb . Thanks ffg or the video I've got the identical trimmer

Just subscribe to your channel. I really like the way you explain what you are doing.

I was about to order a brand new weed eater video is very useful

The reason it wasn't purging was because of the diaphragm you used didn't have the purge hole on it. Should've double checked it before going with a new carb.

Those Stihl trimmers, the FS 38, 45, and 55, spit a lot of oil out of the muffler. I add just the right amount of oil. So when I'm done with the machine there's little spots of oil on the machine. It gets on the pull cord, fuel tank, and even the front cover. It's a pain, and I have to clean it constantly. The stuff on the fuel tank definitely was not from exhaust. That was like spilled gas.

I would have installed a new OEM carb kit (if available). A lot of newer equipment doesn't sell carb kits any more. Your only choice is a new carb. That is the result of USA environmental standards (i.e. California). I'm not sure if this impacts on Sthil at all but I had a generator that needed a carb kit and this is when I found out this info.

i just did one i rebuild the carb just fine but also ordered a carb so now i have a back up for next time

If I was ordering parts within Australia & I was in a hurry I would order just the pumping diaphragm locally & I've had to spend $30 AUD on a brand new OEM type carburettor for a Stihl hedge trimmer after a local eBay seller dudded me with a crappy aftermarket carburettor. I've had no problems with using $16 AUD carburettors which come directly from China if I am prepared to wait for it. BTW ,the switch can be pulled apart & cleaned as it gets jammed up full of crap,I've had to do that on a Stihl leaf blower !

I would of taken it apart again and gave it a carburetor bath. Great video. 👍👍👍👍👍

Have you ever had a machine you just can't fix? I like stihl but find Honda last a lot longer. Love your vidoes 👌

Your air compressor is very valuable for cleaning equipment. Blow the crap out of it and you can get most of the dirt off. No prime could also be a line with crack in it. I use aftermarket carburetors all the time. However, I do everything I can to save the original Zama carb.

Good one mate.. I use copy carburettors and have no problem at all.. can be a pickle to tune sometimes.. ta for the video. I would of got a new carburettor after the first clean..

What cleaner did you use prior to diagnosing the problem. I agree with cleaning prior ... A clean machine slows for seeing leaks and other potential issues easier.

Great video, very helpful

Very helpful Thanks!

Well done video. Given the unmaintained look of the unit, I would have assumed that the carburetor was shot, poor and old fuel having done its damage, and at $10, bought a new carb right away. I am really curious, though, as to what is a “knock-off”. My Stihl trimmer has an OEM carburetor made in China. Would like to know what is the actual difference between Stihl’s made-in-China carb and the made-in-China “knock-offs” beyond what the marketing folks would want us to think.

Very informative mate thanks

Great video! I have the FS55R and am ready to trash it. I have done everything to get it to start and nothing works; have done the following: Replaced plug, coil, carburetor, cleaned spark arrestor, and more. Even starting fluid put in the carb or plug hole will not get even a hint of starting. My spark tester does show a spark but I thought it may have been weak so I put in a new coil and still nothing. Any thoughts before I scrap it?

Could you make a video on why gas might be leaking out of the carb when I put gas in the tank or when I prime it I have a Sthil FS55R

Thank you for information.

I noticed the replacement diaphragm was different from the old one. Check the alignment of the fuel hole on diaphragm.. could that have been the reason for it not working after the service??

new metering diaphragm didn't have extra hole where draws fuel look closely new and old you will see

I would have installed the correct metering diaphragm. The metering diaphragm installed does not match the primer base, hence why the carburetor would not prime after service. Well put together video though, easy to follow and helpful.

Great video ! 👍

Great video

New carburettor is a great time saver. Also eliminates a second fix, if the old one fails again. Mine seems to quit after five minutes warm up, with new carby fitted. Something loose at the coil end perhaps.

A non priming unit is either fuel blockage, check failure, or vacuum leak. Since it setup a long time, dump fuel into container and try blowing low pressure backwards through the pickup tube to the tank: carb cleaner, dust off, brake clean... as long as it can evaporate/won't leave lines filled. Then ask yourself why you went cheap and re-used a carb gasket in the first place - if that wasn't a problem, it will be [maybe soon].

I would have checked the fuel lines and filter to make sure they weren’t plugged. I would have taken the carburetor apart again and after I rebuilt it, I would test it in a small bowl of fuel. I find it very strange that the primmer system wasn’t working. It must have been an issue with the one way valve. Buying a new one would be my last resort, as I think buying a new one is sometimes just being lazy.

I don't know if I am just lucky but my identical power attachment wouldn't start and I was sure I needed to buy a new carb...which is what was recommended. I was curious to figure out if my gas was too rich with oil and I put a little strait gas... still didn't start. Then the next day for some reason I thought just one more try. it started and ran perfectly. I'm thinking that somehow the strait gas cleaned the carb jets and presto....

I enjoyed your video, but i have trouble starting my trimmer when hot, have you any sugestions

great video... would like to ask what did you use to clean the unit?

Would you agree that after i do all the cleaning and the bulb doesn't fill with fuel I need a new carburetor?

Fine job thank you

I was working on this same Stihl for two couples of days ,I replaced carburetor , but still hard start , what will I do next??????

Have same problem on mine Fs55rc Took mine apart cleaned it up put back worked for little bit took apart again ordered new carb and kill switch

What do you use in the spray bottle to clean the engine with please

very very nice slow and good explanation

New carburetor!

cheaper to replace carby when you add up all the parts you get with it some include spark plug gaskets new fuel lines and filter. You would pay half of the cost for a carby kit

Wow that cleaner works good. What kind of cleaner are you using?

Thank you for your video help's a lot. I would have got a NEW cab there cheap as it is than to waste hours resolving the issue. Time cost money today. Great video

Just a new Chineseum carb, my luck with the is about 80% , 2and 4 cycle. Not so much for Stihl carb clones

By the time you get just the gasket set for a Zama and clean the carb it would cost much more than a new one. So for 10.00 and a quick turn around time...that's a no brainer, But what do you do when the carb is popping off the filter cover...just like a back fire from a vehicle

The cold/warm start button won't stay in place??

I would have tried cleaning it with carburetor cleaner spray and if that didn't work then I'd buy a new one IF the replacement was as cheap as you say, cuz even the Chinese ones for my weed eater feather lights are about 50 bucks

👍great vid

Hi Home Garage. My neighbor brought me an FS 55R and said that it was bogging down after about 15 minutes of use. I cleaned off any carbon on the spark arrestor. Fuel filter and air filter are clean. If this doesn't work, rebuild or replace carb? I was trying to take to paths of least resistance first. Any help would be greatly appreciated.

I would have cleaned it and used whatever original parts I could so that the only thing that costs me is my own time. Carb cleaner is available in a spray can and in many cases you can just leave it in a bowl. I never needed an ultrasonic cleaner to do it. Then again I’m old fashioned :)

OK so I replaced the primer bulb in mine mine is dirty I also replaced the filter it’ll run by when I get going it stops. Any ideas

How come my still weedeater fs100r win I start it it stocks me like real hard to u have to let go of it

Hello home garage just wondering whats the link for the carburetor

I need that little diaphragm gasket but I can’t dont the specific one 😓 can you help me?

My carburetor puts fuel in the motor while im priming the lines is that normal

Can the weed eater work ONLY on gasoline or it must use mixture?

Any more I just replace carbs usually have 10 plus dollars in parts and carb cleaner anyways so for the last 10 years or so I just been replacing carbs as a first thing if it stops running

I would have used a pressure washer to clean it first then just replace the carb as you did. Have the same unit (3 of them) same outcome on all from a free given to me

I thought that model was made in the kombi system. I didn't know they made that engine in a trimmer to.

Can you add a link where to purchase the new carb