STIHL FS45C Carb fix Primer Wont Start Fix Carb Kit Available

Repair Kit Available
STIHL FS45C with carb problem. Carb kit and primer.
Step by step instructions. Clean carb and install carb kit.
This trimmer sat for 6 years unused. Carb was in bad shape.
Fix yours. The original carb is always the best way.
Runs like a brand new one !!
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[@midtdal]

I really got a lot from this video. I love the tip about checking out the operation of the primer bulb by testing it in a container of mixed gas by running fuel line from the suction side of the carb and watching gas squirt out of the primer bulb side. I was also worried about the welch plug and this answered my questions.

[@IFIXIT4U]

Glad it was helpful!

[@orbitalblimp]

Great tip on checking the primer bulb is working before installation of the carb!

[@IFIXIT4U]

Glad it helped

[@MrThatguy421]

Thank you so much. I've been struggling with my weedeater, and chainsaw. Some charlatan charged my father almost $500 to not fix them. Your video helped me figure out that the only issue was the throttle was turned so low that it couldn't prime. I'm about pissed but thankful. I just went through cleaning my weedeater carb before I realized the problem. I'm pretty sure it's going to work on the chainsaw as well.

[@IFIXIT4U]

Thank you

[@geraldbasford6713]

I watch a lot of videos and will say this is the best yet. It is so good to see a real pro making videos. I have a small engine repair shop myself here in the Napa Valley CA. I still go to utube on occasion for things like honda commercial mower cable replace because they are a variety of diff models or other issues.Thanks old timmer

[@IFIXIT4U]

Wow, thanks!

[@deansawich6250]

Super! Thanks for all the detail and great visuals.

[@IFIXIT4U]

Many thanks!

[@robbrobb2161]

Excellent video on this carburetor. Helped me out quite a bit. I used a replacement carb, but now I have a better understanding of the components

[@IFIXIT4U]

Thank you.

[@rickthelian2215]

Thank you for this video from down under in Sydney Australia

[@brknbike]

For anyone looking for the sweet yellow 5/16 nut driver, like I was, it is a Snap -On NDD110AY - a little pricey, but when it can be spotted across the room when you need it, worth every penny! - Enjoyed the vid - well done, - THX!!

[@IFIXIT4U]

Thank you

[@rpm773]

i have the same make/model. Your video saved me some money, but better yet I learned something new watching it. and fixing mine Thanks!

[@IFIXIT4U]

Great to hear!

[@sierrawhiskey5155]

This Sir is one Bad Ass Carb rebuild ! The holy Grail of Dried up diaphragms, Cool stand, Sea Foam, WD4d, needle & seat like a Boss, and a demo of the machine running on the rebuilt carb. Yeeea Haaah! Hot-Dawg!

[@IFIXIT4U]

Thank you very much ! : )

[@wickedleeloopy2115]

Had the same problem. Followed your video... can't believe it. It actually fixed it. To think I was concidering buying a new carb or even concidering converting to a battery tool.. good video.

[@IFIXIT4U]

Thank you.

[@bill2jamyt]

Best carb rebuild vid on YT. I've been watching multiple videos for hours trying to figure out diaphragm metering lever adjustment. Ez... Thanks

[@IFIXIT4U]

Thanks 👍

[@DizConnected]

Very detailed and informative! Thank you!

[@IFIXIT4U]

Thank you

[@billbobs]

Excellent video! It gave me the information needed to understand why I was getting no gas to the primer bulb. In my case the line had collapsed inside the tank. I got gas after running a test fuel line as you show, so the problem had to be with the supply line.

[@IFIXIT4U]

Glad it helped thanks

[@holidayfinn]

Thanks for making this video. Now I know what’s wrong with my carburetor! This has been very helpful and informative! I will let you know how it turns out.

[@IFIXIT4U]

Thank you!

[@JuiceBanger1]

well how did you get on?

[@deanzhot12]

Good video.... Exactly what was needed...

[@IFIXIT4U]

Glad it was helpful!

[@colossus5752]

Thanks a million sir👍

[@IFIXIT4U]

Thank you.

[@shane8911]

Like a brand new one! Hell yeah haha. I knew that’s all mine needed

[@IFIXIT4U]

Thank you. : )

[@keithooo123]

God bless you buddy. The fuel trick you showed is the only way I can get my $600 hedge trimmer to start each year. I only use it a few times a year and it is hard to start. but after using your trick it starts up and runs great. I might buy a cheap carb to have around just for when this method fails me in the future. instead of a ultra sonic and carb repair kit method.

[@IFIXIT4U]

Glad to help. Thank you.

[@peterkovacs8354]

Thx a lot Sir!

[@IFIXIT4U]

Most welcome!

[@dtm7909]

Great video !!

[@IFIXIT4U]

Thanks!

[@georgepoirier9014]

Thank you.

[@IFIXIT4U]

You're welcome George

[@albertdelay6458]

Great information.

[@IFIXIT4U]

Thanks for watching!

[@emmanuelmeyermeyer1083]

Very good video on Stihl carbs and info

[@IFIXIT4U]

Glad you liked it

[@graymouser7649]

more vids ,please love em

[@IFIXIT4U]

Working on one now. Thanks

[@sandyhunter66]

Awesome video helped me heaps . I'm in nz

[@IFIXIT4U]

Thank you

[@peterbach3416]

Well done sir!

[@IFIXIT4U]

Thank you

[@charlesoverton]

Thanks, this was a good one.

[@IFIXIT4U]

Thank you

[@stevemash3066]

Perfect.. Keep up the good work..

[@IFIXIT4U]

Thank you! Cheers!

[@watermanone7567]

You do nice work, I get lots of carb work from old gas and ethanol gas issues. Thanks for the video's.

[@IFIXIT4U]

Thank you.

[@sterlynali6679]

Thanks I learned alot

[@IFIXIT4U]

Glad to hear it. Thank you

[@troy4219]

Thank you 😊

[@IFIXIT4U]

You're welcome 😊

[@cb400fhonda6]

Xcellent video Testing details Perfect Lots of info Thanks

[@IFIXIT4U]

Glad you liked it!

[@anishchackoacp6002]

Very nice and informative video Thanks. & I need stihl FS250 trimmer carburettor (original) what can I do?

[@IFIXIT4U]

Check with your local STIHL dealer. thanks

[@harleyd301]

Excellent video

[@IFIXIT4U]

Thank you very much!

[@mp3625]

Good info

[@IFIXIT4U]

Glad it was helpful!

[@miguelangelsalinascuevas2135]

Merci bien,

[@MNpicker]

Good stuff 😎

[@IFIXIT4U]

Thanks! 😁

[@thomastaylor5766]

Good video.

[@IFIXIT4U]

Glad you enjoyed it

[@gilpicard6024]

Just hooked on to your site. Subscribed

[@IFIXIT4U]

Thanks

[@jessekurisko5659]

At the beginning of the video when you poured some gas into the carb. If it didn’t start up, what would you have done? I’m having that problem now. I do have spark so I’m not so sure what to do.

[@IFIXIT4U]

If you have fuel and you have spark/fire. And still wont hit. Then I would look at mechanical / crankcase integrity . Check compression. Look at piston and cylinder for scoring through exhaust port. Look for worn main bearings and seals. Look for air leaks. Good luck. Thanks

[@mooregoodink7734]

Hello Glenn, Thank you for your invaluable help in the past. My current problem relates to an Echo strimmer that starts instantly and runs beautifully, including when I tilt it 45 degrees to the right when trimming ivy. But tilting it 45 degrees to the left causes the engine to stop in around 15 seconds. Any suggestions as to a remedy?

[@IFIXIT4U]

Sounds like a bad check valve in the nozzle ( check nozzle ) Time for a new carb. Thanks

[@mooregoodink6971]

@@IFIXIT4U Glenn, thank you, but where is the nozzle? Is this the area that Zama refers to as the primer base assembly? It contains two one-way check valves I believe.

[@bmorestance]

Finally someone who opens the thing up. I have an issue with Stihl FS110R trimmer. I cant figure out where 2 parts go that came out of carb. Took carb off and removed premier bulb and all the black pieces. I have a Spring and White plastic piece popped out from somewhere. But I cant figure out how to put it back together. Do these parts ring a bell or could it be to a different part of the carb? Its a plastic circle white piece that can fit the Spring inside. The spring is not a small spring, its prob around 5/8ths. Any help appreciated. I thought it went on those black screens... Otherwise, I will try removing those pieces to see if it helps. Thanks! update - i think i found it... on the bottom of the carb.

[@IFIXIT4U]

Thank you

[@johnweakland6887]

Hi I highly recommend you invest in an ultrasonic cleaner to help clean your carburetors, they work great at cleaning carbs and other things.

[@IFIXIT4U]

Yes they are great. But most of the time I see bad diaphragms and not so much a dirty carb. But yes they are great for dirty carbs and other things that just need to be cleaned. Thank you

[@roberte.watson8155]

This was great. Now wondering how to start from scratch to make necessary adjustments for High, Low, Idle? Thanks

[@IFIXIT4U]

Its different from carb to carb. 1-2 full turns out will generally get you started . Adjust from there. Thanks

[@roberte.watson8155]

With the engine running at full speed after starting, I tried to adjust to high speed to bring it down a little bit. And then to adjust the low Speed. The needle valves had no effect whatsoever.

[@IFIXIT4U]

Turning the screws in to lean ( clockwise ) . Should kill the engine if you keep turning them. If it keeps running. Something is wrong inside carb. Its getting fuel from somewhere.

[@mooregoodink7734]

Glenn, Might you know how the carburetor of a 4-stroke (Troy Bilt TB4BP leaf blower) receives its impulse to activate the pump side of the carburetor? Using the primer bulb, this carburetor circulates fuel to and from the tank efficiently, but I'm unsure if the engine's alternating positive and negative pressure system is engaging the carburetor. Though it starts and runs for a few seconds when gasoline is poured into the intake, it won't start and run on its own.

[@IFIXIT4U]

The pump diaphragm gets its pulse from intake manifold negative pulse. Thanks

[@mooregoodink6971]

@@IFIXIT4U Thank you Glenn

[@mattiel9156]

When I use the primer bulb to prime the carb...a lot of fuel spills out de carburetor. Do you know How I can fix that? The fuel is not going back in to the tank but it exits on the intake and eventually its spills out.

[@IFIXIT4U]

Hard to say from here. My best guess is needle not seating under metering diaphragm. That would allow fuel to pour out. Also bad diaphragm or carb not assembled correctly would also cause it to leak. I would take the carb apart and do a very good inspection. Thank you & Good luck

[@mooregoodink7734]

Good morning Glenn, I have a McCulloch Mac 100-HD strimmer with 125psi compression, spark at the spark plug, an unimpeded exhaust system (no mud daubers) but will not start on a half-capful 40:1 fuel-mix prime introduced to the crankcase. Any thoughts as to how I might bring this little machine to life, Glenn?

[@IFIXIT4U]

Might be an air leak. Check cylinder gasket, crank seals and gaskets behind carb. I would recommend a crankcase pressure test if you have the tools. Thanks

[@mooregoodink6971]

@@IFIXIT4U Thank you Glenn, I'll check for air leaks as I have a Mityvac 8500 vacuum/pressure tester. Before requesting your help, I had thought my non-starting trouble might be caused by a faulty coil. When grounding the spark plug and pulling the starter cord, I noticed spark at the plug tip for the first five pulls or so, but then the spark vanished.

[@mooregoodink7734]

@@mooregoodink6971 Hello Glenn, thank you again for your helpful suggestions mentioned above. I machined two plastic blocks both under 2in diameter and approximately 1-1/4in thick with bolt holes to secure them to the exhaust and induction ports and then, via a separate port, applied 7psi of test pressure to the engine's internals for several minutes by a Mityvac tool. The engine held the pressure without leaking, so I assume the ignition coil is the likely culprit. Might you have further thoughts Glenn? Very best as always -Vm

[@mooregoodink7734]

Correction: Glenn after I wrote last evening I wondered if a clear passage was available to the crankcase for my pressure test or if the piston was blocking the port, which it was. I repositioned the piston and reinstalled the blanking block and old intake gasket and it leaked on every successive attempt. I'm still not sure how it sealed the first time but a new intake gasket seals it. As usual, your initial diagnosis was correct. Thank you so much. -Vm

[@mooregoodink7734]

Good morning Glenn, my Husqvarna 142 chainsaw has run well for years, but recently it would stop after about five minutes running and wouldn't restart for a period of time. So, I dismantled the carburetor which appeared fine, but then, behind the carburetor, I found the impulse hose badly worn and cracked and replaced it. Also, I noticed the fuel hose badly kinked and so replaced it as well and carefully reassembled everything. Now the chainsaw won't run without choke. I've dismantled it again and checked for an air leak but cannot find any. Might you have a suggestion to remedy this problem?

[@IFIXIT4U]

Might be time for a new carb. Thanks

[@mooregoodink7734]

@@IFIXIT4U Glenn, thank you for your kind response. Maybe so, but in the meantime I replaced the intake tract gasket and now the Husqvarna 142 operates without the choke and runs at mid- and full-throttle but not at idle. I notice a substantial oil leak around the primary chain sprocket, which presumably relates to a crankshaft oil seal. Might this cause my problem?

[@IFIXIT4U]

Yes a leaking seal can cause an air leak and a lean condition.

[@mooregoodink7734]

@@IFIXIT4U Thank you, Glenn, for taking the time to response.

[@destaniecampbell7504]

I've got an fs40c how do I tell if the Welsh plug is blocked or needs to be fixed

[@IFIXIT4U]

The only way is to remove the welch plug. If I kit a carb and its still not running right and I have double checked everything, its usually time for a new carb. Just my opinion. Thank you.

[@destaniecampbell7504]

@IFIXIT4U ok well should my welch plug have a red ring around it? This is actually my cousins weedeater and it did start 1st pull every time then it'd die now its sat 4yrs and still would start 1st pull even tho i couldnt get anything in the bubble..... til I took the carb apart go figure* and literally intake was clogged with gummy fuel but now it won't even try to do anything

[@mooregoodink7734]

Glenn, I have an old Homelite string trimmer, so old the Zama carburetor (CIU H10B) is made in Japan, not China, and it's presenting two problems. First, the small-bore fuel hose (with filter on tank end) is connected to the carburetor's metering port and the larger fuel-return hose to the pump side. Will this work as it seems to be in reverse order? Second, I've cleaned the carburetor and installed a new Zama rebuild kit and everything looks well, but when tested, it will not draw the fuel through the circuits and return it to a glass jar containing the fuel mix. I assume that somehow I've lost vacuum in the fuel circuit--there's no snappy chirp from the new purge bulb. Any thoughts? Earlier, I poured half a capful of fuel mix into the crankcase and the machine immediately burst into life.

[@IFIXIT4U]

If you think the fuel lines may be backwards then reverse them and try it. The ( fuel pump side ) of the carb is where the main fuel line comes in at. If the primer check valves are bad and not pumping fuel then you may need to replace primer. Hope this helps. thanks

[@mooregoodink7734]

@@IFIXIT4U Glenn thank you, for you are the most helpful, reliable man--especially on a Sunday afternoon! You mention replacing the primer. Is this the part that contains the two check valves and the purge bulb? Earlier, I primed this carburetor, using conventional hose routing and depressed the bulb slowly about 50 times and succeeded in getting fuel to the metering reservoir, which then began flooding into the venturi bore via the tiny discharge ports--I assume. Does this further information suggest defective primer check valves? I notice that compressed air blows though both of them, no restrictions, from the bulb mounting face.

[@IFIXIT4U]

Yes it sound like check valves are bad.

[@mooregoodink7734]

@@IFIXIT4U Glenn, thank you for your reply. I think the primer check valves are stuck open. I initially soaked the assembly in Seafoam overnight but to no avail. Now, I've set them in gasoline in an attempt to free them. The carburetor is vintage and I'm keen to get it running again, but I doubt a replacement primer assembly available if I fail.

[@mooregoodink7734]

Glenn, the Zama part number of the primer base assembly for this CIU H10B carburetor is A056001. If you have access to one or a replacement you think might fit, please say. I'm located in north Georgia.

[@mooregoodink7734]

Hello Glenn, I'm attempting to start an Echo strimmer that's been stationary for several years. I tried starting it with a prime (pouring half a capful of fuel mix through the open venturi into the crankcase) but no joy. It has approximately 110psi of compression and electricity to the spark plug. I then removed the carburetor and cleaned and tested it and found the one-way fuel return valve in the white plastic primer base assembly (near the purge connection) stuck partially open. This, I assume, would deprive the metering diaphragm of its operating vacuum, preventing the needle valve from opening. But, still, I wonder why the prime test (half a capful of fuel in the crankcase) didn't bring the machine to life. Any ideas Glenn?

[@IFIXIT4U]

Sounds like it has everything it needs. Should have hit on the prime. I would check for stopped up exhaust.

[@mooregoodink6971]

@@IFIXIT4U Mr. Glenn, you are the master! Mud dabbers had comprehensively sealed the exhaust system. Thank you for your guidance.

[@mooregoodink7734]

@@mooregoodink6971: Hello Glenn, I cleaned the mud dauber's dirt from the exhaust box, spark arrestor, and exhaust port of the little Echo SRM21OU strimmer, and it started but ran roughly. So, I fitted a carburetor rebuild kit and it still runs rough. It will only start and run when alternating from full choke to mid-choke, and yet for five minutes yesterday, it ran like a race engine without choke, but then returned to it's old affliction: full choke to mid-choke no throttle. I sprayed its intake gasket with Permatex High Tack sealer in case is was sucking air, but still no joy. I don't have sufficient experience to determine if it's suffering from fuel restriction or an air leak. Any thoughts you have on this would be much appreciated. Cheers -Vic

[@mooregoodink7734]

Glenn, please disregard my last comment. I own a newer model of the Echo strimmer and removed its fully functioning carburetor and installed it on the SRM21OU. The troubled machine started instantly. So, I ordered a new carburetor for it. I was startled by the effectiveness of the carburetor swap and assume one of the faulty carburetor's internal passageways is blocked as, in the end, no amount of pulling on the starter cord prompted life. Cheers and thank you again for all your kind assistance. -Vic

[@thomashatfield5628]

Tom Mixer Great video. I still cannot get fuel to prime before fitting carb back? Thanks again.

[@IFIXIT4U]

The primer block may be bad. The plastic part with the check valves. You can probably find one on-line. Thanks

[@calvinsmith3697]

I am having trouble replacing the cable line

[@IFIXIT4U]

Use WD-40 on the line and it will be easier. It will go through the tank easier if you cut a point in the fuel line. Thanks

[@mooregoodink7734]

Glenn, thank you for this exceptionally capable video. My Stihl FS46C trimmer had lost its carburetor pump-side action, though it burst into life when I poured a small cap full of fuel mix into the crankcase. But, clumsily, I lost a tiny spring from a check valve in the metering block. So, my wife ordered a new carburetor, which was fine until she told me it cost $15, including two filters, etc., etc. Now, I'm wondering how dubious the quality I'll receive in three days' time. How could a complex carburetor (ZAMA C1Q S71) and associated parts be produced and sold for $15? Can you say from where you purchase your parts? Always from a Stihl distributor or other sources? Cheers, Victor Moore

[@IFIXIT4U]

Good luck with the China Knock-off. Maybe you will get lucky. I never have any luck with those. I can almost always fix the old carb with a repair kit. That saves my customers time and money. I get Zama carb parts from a Zama distributor. We are a Zama dealer. You can get Stihl parts from your local Stihl dealer. Thank you

[@mooregoodink7734]

Glenn, might you have a tip for cleaning the internal surfaces of plastic fuel tanks?

[@IFIXIT4U]

I use a hemostat with a small piece of cloth and some carb cleaner and alot of elbow grease. thanks

[@mooregoodink7734]

@@IFIXIT4U Glenn, I have a Jonsered string trimmer (made by Husqvarna) that hasn't run in years. I cleaned the carburetor (Zama C1Q EL12) as you have instructed, installed new metering diaphragm, air and fuel filters, fuel hoses, and remote purge bulb. The machine started but to encourage it to rev, required two and three turns out from bottoming on the high-speed and low speed adjustment screws respectively. The spark plug colors are grayish. The problem is that it often bogs when throttling and sometimes stops entirely. Might you have a suggestion as to how it can be made to accelerate without bogging?

[@IFIXIT4U]

Make sure exhaust port and muffler are not clogged up. Might still be an issue inside carb. I would tear it back down and soak it overnight in seafoam. Sometimes you get that carb that never runs right. It doesn't happen very often but you may need a new carb. I would buy OEM . Those knock-off china carbs are junk. thanks

[@bmtisme8292]

Just buy a new carburetor. I found one on ebay for $16.00 total from topgearsltd shipped in mail. Remember you have to take your old carb off and get numbers off carburetor. It fired up first pull! Now some small air fuel speed adjustments and your set! Nice video though and thanks for helping.

[@IFIXIT4U]

The china knock-off carbs are cheap but I've had really bad luck with them. The quality is terrible and never seems to run right. Always have to be moving the adj-screws. The OEM carb is the best way to go if you can do it. That's is great that you found a good one. Thank you

[@bradwells8643]

All I'm saying people know 99% of the time if someone is full of poop this isn't one I wish dude was my next door neighbor I rather pay him to maintain my small engines