Why shops replace two cycle carburetors.

[@deeman77777]

Great video! As others have mentioned there are lots of us backyard mechanics who install rebuild kits and the device still does not run. We pull our hair out trying to understand why since everything looks okay. Now we know the reason - thanks brother!

[@markluxton3402]

I have rebuilt a few, mostly Tillotson. Most of my vintage saws don't have check valves, I think. I'll have closer looks when one of my saws needs another rebuild or cleaning. There are several good mechanics on YT, showing how to service and diagnose carburetors. I only just got a simple pressure checker which will make for much better testing....before starting the saw lol

[@dublloyd9625]

your the first person i ever saw that knew about the function and critical nature of this check valvethank you for sharing most people dont have enough experience from when we used to repair and not replace parts

[@dalestaska1807]

Many thanks for posting this. I’ve watched dozens of 2 cycle carb rebuild videos here and nobody explained that about the check valve. Thank you brother!

[@alext9067]

Ditto.

[@markluxton3402]

You were not following the better mechanics then. If it has check valves, check them.

[@phyllismacevicius8821]

I am just learning carburetors at the Stihl dealership I work at. Thank you for posting this video. You taking the time to take the check valve out and show it to us was very helpful.

[@alext8828]

Kudos. The black art of carburetor repair, like many other skills, is gold. Now you have to make up some hocus pocus to go with it. I knew a broadcast engineer that would make the sign of the cross on a piece of equipment before he fixed it. Everyone went to him after they exhausted all their own ideas. He always had the answers. Keep learning.

[@carlodonnell146]

Mine is like that and you are the first person to mention that check valve; you-tube is great, except that no one explains everything, so you have to watch 100 or more videos to get the whole story. I wondered what that brass stopper is and it can't be removed without damaging it so I did not want to trouble it; I have to order a new carb. Thanks!!!

[@mikey6071]

After hundreds of videos, reading for weeks, finally I have the explanation of how to test the check valve, knock it out, and replace. Thank You!

[@alext8828]

True. Funny thing is, I commented on this video a year ago and didn't remember any of it. This is important stuff. I must be losing it.

[@markluxton3402]

You do not have to remove it to check it. You do the same test he did in the video, but while the check valve is still installed.

[@jeffblack1644]

Thanks for covering how to replace that valve. My Poulan 3400 had a bad one that I tested the way you describe but i was going to try to pry mine out with a screwdriver before I watched your video. Thanks again!!

[@wcjcnc]

Jeff Black No problem. Hope you get it going.

[@Damon-s]

You just saved my blowers life i was really fed up Ready just throw it in the burn pile rebuild it. Took back apart like did i do wrong. No. spent hrs watching dumb videos not explaining diddly. Then this yea im just going 2 replace it. Thanks so much 🙏

[@doncook3584]

First video showing and explaining check valves big thumbs up

[@LTDan-pk3mx]

A Big Thank you... I have a Zama RB-27 on an echo PAS-225 that leaks gas into the cylinder after priming, then of course Floods out the exhaust.. Soaks the plug & every thing else.. I going to rebuild but will check the check valve first... Again Thank you for the Great education!!

[@killer2600]

I'm having an intermittent but consistent issue with that very check valve on a different Walbro carb. It'd prime up but after a failed start attempt, the primer bulb would just suck air. After messing around with it, trying to find where the air is coming from and/or trying various pressure/vacuum tests it'd work again and prime up like it should until it'd mess up again while trying to start the saw. Initially, when I first went about repairing this saw I thought it needed a rebuild kit for the typical reasons of it being an old saw that had been sitting for years and always had ethanol tainted cheap 87 octane pump gas/oil mix for fuel. The kit did make the saw work better at the first start after the rebuild but the joy of it being fixed and working as it should didn't last very long. Been chasing the running issue ever since until I noticed the primer sucking air. After pulling my hair out trying to find the source of the leak and the associated sucking sound, I've found the culprit. I can see why shops just replace the carb. Had I done that instead of trying to rebuild it, I would have saved many hours of working on this saw trying to find out why it's running so poor and hard to start.

[@kensmechanicalaffair]

That's the beauty of it. I'm pretty sure you gained a shit ton of information about repairing and diagnosing a two stroke carb.

[@killer2600]

@@kensmechanicalaffair That I have and honestly I don't regret the opportunity to learn. I could work in a small engine shop now :D

[@threejackcity4471]

great video. For some of us backyard mechanics the game is trying to do stuff as cheaply as possible and we don't factor in the time we spend. Obviously, those running a shop don't have that luxury. For me it's more the challenge; understanding the check valve helps and I may even try replacing one or two.

[@donjohnson3701]

Great explanation! I have a leaf blower and a chainsaw that I just did tuneups on and instead of dealing with the carbs I just replaced them. I found that the carbs like Zama are built in China nowadays so I can order a kit with carb, fuel filter, fuel hose, and even a spark plug for around $20.

[@KevinMaxwell-o3t]

The no-name Chinese carburetors you can find on Ebay are not Zamas. However, they do seem to be fairly well made, just the same.

[@josephcrowshaw950]

Very helpful video, thank you for posting this.

[@jameskrivitsky9715]

I have a Poulan 22 inch hedge trimmer which I am repairing after a couple years in the shed. I am able to get it started but it runs high RPM and won't low idle. Upon removing the carb, I see that the rework needs more than just hoses and fresh fuel. I noted that the purge bulb was stiff so I replaced it with a new clear bulb but it is not circulating fuel properly. I flushed out the tubes with carb cleaner which help a little. I also tried some low pressure compressor air and noted that the purge check valves had issues. The purge bulb is mounted on the carb and I could not find the individual part so I proceeded deeper. I removed the pressed / glued aluminum disc and found a spring, a brass insert / jet and a tiny rubber flap about thin as paper and smaller than a pencil eraser. It had a minute tear where the spring broke the rubber flap. I am going to see if a small drop of super glue on the rubber disc will last once subjected to non-ethanol gas /oil . If you try to clear the check valve by inserting a wire, you will destroy the tiny rubber flap.....so DON'T. I found this out before when I was less educated on small engine repair.

[@elebeu]

I understand as a business owner or as a novice, homeowner mechanic, replacing the carburetor with new is the way to go... but I enjoy the challenge of diagnosing and repairing the original equipment.

[@simplybeanjelly]

Thanks so much for this video, I COULD NOT figure out what was going on, my weed eater is literally leaking straight gas out of the check valve, I'll be getting a replacement.

[@john7017]

Great video! Now I know why my Zama carburetor is blowing back air bubbles thru the fuel in the tank filter. I rechecked my work 2 times after he rebuild. It's and old Homelite ST 185 and the carb isn't available anymore.

[@killer2600]

If it's doing that when you're pushing the primer bulb, it's not the carburetor check valve. It sounds like you have your fuel hoses connected incorrectly - more specifically it sounds like you have the fuel filter connected to the primer bulb.

[@mikespain8655]

Thanks for explaining check valve. Shops mark up the new carb, and labor to remove and install new carb, which saves them time and is profitable. Rebuilding and cleaning old carb takes more time and no new carb sold for them. Also, people like new these days instead of rebuilt.

[@georgedurivage4690]

I have heard it explained but have never seen it done. Thanks.

[@randywetzler5976]

I was working on a Stihl weedeater with a carb similar to this. Mine had what I refer to as an idle (pilot) jet incorporated into it. Thinking it was clogged (common problem a lot of small engines) I forced a wire through it and must have popped out the check valve. I felt something give and noticed a small rubber part but no trace of the other tiny parts. Ended up replacing the complete carb. Mine was a Zima C1Q series S58. I still have that carb if anyone knows a part no. for the check valve I'll be able to repair it for a spare. I was able to knock out the valve body after watching this video.

[@jwayne777]

Great video. Thank you. The manufacturers could made them with flat brass discs instead of rubber. But them that would make thongs last forever

[@Indeewoods]

Great video. Even the actual carburator manufacturer videos don’t speak of this. I have an MS-250 that ran great for 4 years. One day I used some fuel with 10% ethanol in it and it started bogging. I think the issue is that check valve.

[@wcjcnc]

Yea, probably was a check valve. The tiny check valves in the carbs on hand held equipment are very important. If the primer bulb doesn’t work it’s usually a check valve. The check valves can be ruined by regular pump gas in just a few minutes. I’ve seen brand new equipment not work right because regular gas ruined a check valve. For ANYTHING hand held you really need to use ethanol free gas.

[@Indeewoods]

@@wcjcnc ya I always use Shell 91 octane. I’m in Canada so always wanting to support local so I tried “Ultra 94” but it does have 10% ethanol and not sute if it was a fluke or it happened that fast but 1.5 tanks of fuel is all it took to start bogging. I thought it was water in the fuel so swapped back to my regular fuel and it ran fine but only for a couple tanks then bogging again. Unless the ethanol just broke up some crud that may have slipped past the fuel filter?? Not sure but I was unable to clean the carb so replaced it and problem solved. I want to look at that check valve now I was wondering wat that brass piece was.

[@steadyeddie7453]

These little carbs dont like the ethanol in gas, though the newer 2 cycle equipment seem to be more compatible. The fuel lines and the diaphragm in the carb are the most vulnerable. But if the check valve has a rubber tipped pintle, it will soon also fail. Best to just replace the carb to avoid tearing it down twice. Avoid the frustration. Thanks for the video.

[@Tailspin80]

Great video. I have two Ryobi saws which both packed in recently with carb problems. One has a Ruixing carb which I replaced with a new carb from eBay for £13 (about $16) and it works fine. The other has a Zama which I rebuilt with a carb kit because I can’t find a replacement carb anywhere at a sensible price. It still won’t run and I am guessing the check valves are knackered, so time to bin it unfortunately. I have switched to Aspen2 to avoid the ethanol problems.

[@crossbow1203]

I have had the same experience at my shop. Buy the kit and maybe pay shipping. Boil it out in the ultra-sonic cleaner after removal and disassembly. put in the fuel screen-needle kit. Adjust the arm height. Reassemble the whole damn carb and put it back on just to find out it runs like crap. Then what? Eat the labor and cost of the kit or PO the customer with a saw that still spits and sputters. No throw that POS away and get a new carb! And replace the plug with a good resister plug. Good job guy!

[@carlodonnell146]

but if ethnol damaged the check valve isn't it going to damage the new carb. too? I notice that it has a line on it, should I make a mark to realign it to.? maybe it has to fit in a certain direction in order to function correctly?

[@georgeEPC]

Good video...I have a WJ85 that I'm having a hell of a time with

[@flierbill]

My carburetor costs over $130.00 WG8 446. Good stuff! Thanks.

[@rickpress9773]

Great video. Thank you

[@wcjcnc]

You’re welcome

[@frankcastle5294]

Never even knew these little walbros and zama even had this valve. Explains why most of my rebuilding attempts are failures.

[@killer2600]

It could be check valves but it can also be clogged passageways. The fuel can gum and varnish up clogging the little passageways but the ethanol can also react with the metal and corrode the carb in a harsh way that cleaning can't fix.

[@louiegarcia7527]

where's your bench vise?

[@markkulyas2418]

I like to learn how to fix things, but after messing with this carburetor for days, watching videos, buying a pump and guages and still having problems, if I was a shop I would have $500. Labor into this sucker and its a $39. carb brand new. But at least I get the satisfaction of learning how to fix it.

[@papabits5721]

Water in the shitty fuel, people leave then in garage over the winter and the water freezes and breaks the check valves.

[@maegankafka4540]

Buy a tripod. I have never seen another small engine repair video that mentions the check valve until now. Thank you.

[@DOPEMANCHEW]

If your have problems with a 2 stroke carb just clean it out and get the carb air/fuel mixture right again. It's pretty simple to do. If you do it a lot eventually you can do it by ear easier.

[@kensmechanicalaffair]

Check valve will cause a no start issue, for one because it wont prime correctly the High Low adjustment shouldn't cause a no start unless it's completely screwed all the way in.

[@MOTA_KRAMPUS]

Gerat video, thank you!

[@gregmccarter2176]

Iv been working on small engines for over 40 years.and could always repair saw carbs just by cleaning..now e10 fuel wrecks them..I just bought a new carb for $12.00 on line..

[@CHIBA280CRV]

Fantastic job

[@lesg6693]

Thanks dude! this video will help me....

[@christophercast5290]

I opened the video because I’m working on a Stihl 009 like the saw visible in the beginning. If you have any information on the 009 or the numbers from that carb, could you please share it? I am trying to find a good replacement carb for it but I’m coming up empty handed. Even my local shop is telling me they’re unavailable to get one. Thank you for the tip on the check valves, it’s easy to overlook it. A lot of people think it’s a Welch plug.

[@harrykirk7415]

Nobody in maintenance ever says , "go ahead. Put ethanol in your 2 cycle"

[@1978garfield]

Do you ever use the cheap Chinese carbs or do you spend the money for Walbro or Stihl?

[@wcjcnc]

For anything hand held I only buy the genuine OEM carburetors.

[@Talachachannel]

👏👏👏👏good job people buy aftermarket carb. Under $20 dollars

[@donbrasseaux2564]

I have a carb, on a P3314 chain saw. I have installed a kit, taken it apart at least 10 times so far. The problem is I cant get it to purge through the bulb. New bulb and the bulb work perfectly off the carb. It when I hook the bulb to the carb on purging. Their is a air leak somewhere in the system. I am thinking it may be the check valve in the carb. As you can imagine the carb is a little different from the one in this video, but I would love to send you a picture of it and get your opinion.

[@stephenormsby3662]

Good information. Thanks for posting.

[@colinbilodeau513]

Having trouble finding a Walbro WT419 carb for a leaf blower. Any tips?

[@markluxton3402]

Rebuild your OEM carburetors. They are made better. Buy a knockoff to get you going in a hurry(maybe), or if money is not an issue, buy another OEM carb.. Much cheaper to learn to service your carb.s if you have the time and tools and skills. Not many good knock off carb. rebuild kits from China but one I have heard is ok, CTS. I have an order for 6 of their rebuild kits. The price of 6 for the cost of one OEM kit; hope they are as good as I have heard..The check valve parts don't come with all kits :-(

[@scottfirman]

I use an Ultrasonic cleaner and never have to replace the carb. Other than the stiff or worn out diaphragm, I hardly ever have to mess with that check valve.

[@1956432]

I have a Dolmar PS350 that had an overheating problem. I found that the fuel coming out of the main jet on the carb was seemingly spraying half of the fuel out towards the air filter. I had read on some forums that an exhaust restriction could be to blame. I removed any restriction from the muffler and now the saw runs good until its under load. I feel like the saw should have quite a bit more power. I have messed with the metering valve because it seemed to have what i would call a dead spot where the lever would move 1/2 of the travel and not move the needle at all. Do you have any idea what could be causing the loss of power? theres no carbon build up on the exhaust, muffler is free flowing, air filter isn't clogged. I also checked the fuel filter and the pulse line. like you said in the video "it'll drive you nuts" - I feel that now

[@josephpuchel6497]

People will never understand Nice video

[@iraborton3941]

The shop will just replace it because it's cheaper, the cost of labor to rebuild it is more than a new Chinese carb. Having said that, I rebuild my own Wlalbro carburetors, I have dumped a $12 carburetor on a chainsaw because the carburetor was a Chinese copy anyway.

[@SnookTuned]

Holy shit Danny McBride works on 2 strokes lol. Nice vid man and jk

[@DougHinVA]

good vid and $30 nowadays for an entire new carb is not much cost...

[@SpYucaipaSoCal]

I have trouble with the carbs on stihl 193t saws. The either work run great or deliver absolutely no fuel at all. Even with new soft parts. Could this check valve be the culprit ??? Thanks.

[@wcjcnc]

Stephen Patterson Absolutely. These little carbs can have up to three check valves. If one of them stops working you’re screwed.

[@Kalkaekie]

Awesome tip ! Thanks !!

[@jimgrigsby5017]

Hey that's some good info.rite there I needed that many thanks

[@robwal3665]

Why don't they just sell a check valve with the kit

[@set3777]

Zama Caburetter repair kits e.g RB29 DO include a check valve.

[@frankdigiovanni4946]

Very enlightening thanks

[@rancha83]

How to check it without taking it out of a carb. Can you blow and suck air while its in there?

[@tomalophicon]

On some you can where there is a drilling in the top rather than on the side.

[@comodice905]

ZAMA C1U-K19 JD 21c weed eater air filter soaked with fuel and fuel seams to be splashing out of carb when i remove air filter and run it. any fix for this. also cant find a new air filter online to order.

[@wcjcnc]

Air pressure builds up inside the gas tank. The hotter it is outside the more pressure there will be. Usually the check valve inside the carburetor will stop the flooding while the weed eater isn’t being used. You may have a stuck check valve. Carburetor will have to be replaced. Or, when you’re not using the weed eater, sit it upright someplace and loosen the gas cap so pressure can’t build up. Then, just tighten the gas cap when you need to use it.

[@paulg444]

I thought that was the High speed jet!

[@killer2600]

It is but walbro's name for it is "nozzle check valve assembly"

[@kensmechanicalaffair]

Me too, lol.

[@kensmechanicalaffair]

@@killer2600 Ohhh.

[@foreverwood1963]

I just had a bad check valve on one of my carbs. It just wouldn't prime no matter what. I found that air was coming in from the main jet into the metering chamber. I'm accustomed to the other check valve that can be checked without taking them out. Tell me what does that hole in the side of that check valve connect to is it the high speed needle?

[@wcjcnc]

I really don't know where that passage goes that connects to the hole in the side of the check valve. So many carbs are configured differently I don't even try to keep up with how they're all plumbed.

[@foreverwood1963]

I actually found out through flushing one of my carbs. There's a port under the metering diaphragm that connects to the holes in that main jet. It should flow down through the main jet into the throat, but not come back up into the metering area.

[@charliepearson1678]

you wont be finding a reasonable price on that carb for that Stihl 009 . more like around $100 , but thanks for the check valve info . most of those Dont come out .

[@joematus410]

Good

[@DOPEMANCHEW]

The thing is your scared to mess with a 2 stroke carb! There really easy to clean and to save the customer money.

[@wcjcnc]

I’m scared to mess with a 2 stroke carb? I’m 55. I’ve been doing this since I was 15. I’ve fixed thousands of 2 stroke carbs. Lol

[@stevecollins1506]

perfect video thanks!

[@Jim-ie6uf]

I agree, I don’t even rebuild mine.

[@christopherperdue977]

You would want to rebuild the carb if it's a modified genuine walbro wt-990. Not modified those are $50-75 and the modified one I have was $150. Yeah you can get a China knock off but it's hit and miss if you even get one that performs like a unmodified genuine one. The last one I got the jet adjustment did absolutely nothing so it was worthless because it couldn't be tuned. Moral of the story is buy cheap and buy twice. Take care of your equipment and it will last. I rebuild my carbs at least twice a year genuine kits are $5-10.

[@billcallahan9303]

Thanks! Shaky camera but that's okay! The content is what matters! Oh....where do I buy one for $35.00? Ebay?

[@FireJetty]

dey is on Damnizon up the yingyang

[@grant31781]

What are the symptoms of a bad check valve? My saw will only run at 1/2 throttle and up. Under that it is starving for gas.

[@tomalophicon]

A bit late but yes. It'll be impossible to idle and bog down under throttle.

[@tonykimble3848]

So the reason a majority of small engine shops rather replace them is to save them, 5 minutes of work, on top of the other 15 to disassemble, clean, re- assemble. What ever happened to pride among mechanics?

[@bluelightguy1]

Usually because the customer is expecting it fixed fast and the faster way is to replace the carburetor it has nothing to do with “pride” as you call it.

[@rumplybrute4260]

Have you ever tried to purchase a Walbro WT-417? $130 new with $78 the absolute best I can find.

[@wcjcnc]

Holy crap. I just searched that carb. That’s crazy. It’s just a basic carburetor. That’s odd?? Let me look through my used carbs and see if I can hook you up. Do you have the old one?

[@rumplybrute4260]

@@wcjcnc yes I do and I think the check valve is bad, I can pull air through it and blow through it

[@wcjcnc]

@@rumplybrute4260 If the check valve is stuck open, try spraying some carb cleaner through it. Sometimes you can get the check valve to start working.

[@wcjcnc]

Make sure you’re looking at a check valve. If it’s brass and has a tiny slot in it for a flat blade screwdriver. That’s a jet not a check valve.

[@rumplybrute4260]

@@wcjcnc I've put new gaskets and diaphragms in this carb which it needed. The machine runs good, all is adjusted to perfection. However, when I cut it off and let it sit a few hrs and try to start it back it floods terribally. It causes no problems on a warm restart.. first pull. But after it's been sitting theres no happy medium to start it. It just floods. No, I'm not using the primer bulb. Ideas? The old intake gasket is pretty bad I've got one ordered. May that be the problem?

[@WV591]

they don't replace them they repair them in 10 minutes like the rest of us and charge the customer for a new crab tell them it had to be replaced.

[@kensmechanicalaffair]

I thought there was more than one checkvalve.

[@wcjcnc]

It depends on the carburetor. Some have just one. Some can have as many as three.

[@PeterPetrakis]

Heaven forbid they drill and tap a bolt into the check valve and pull it out.

[@briang4470]

You gotta look at it from their perspective they could potentially waste hours of their labor and money on a rebuild kit, all for it to still run bad and alot of these guys get $60+ an hour labor so if they spend 2 or 3 hours rebuilding it then they already have more money into the carb than just buying and brand new one and it helps cover the shops ass of it messes up.

[@killer2600]

@@briang4470 Precisely, when you're paying labor cost by the hour it can be more cost effective to replace a defective part than to attempt to fix the defective part. When the cost of a new carburetor is cheap, it's the better way because you not just fixing the old used carb, you're putting in a brand new one. For the shop, new parts are also the better gamble when the shop has to warranty the repair. The life of a new part is typically better than a used one.

[@DougHinVA]

get an entire carburetor and put it in place and go on and forget all that working and fiddling. Skip the shop and fees and replace the carb for yourself.

[@silverstar4289]

Doug H. in VA I found a ten dollar carb for my Stihl trimmer EBay after having the dealer rebuild the original twice. I ordered two from China, so it took a couple weeks, but saved money. My ten dollar unit hasn’t failed in years, and the backup unit is still in the package.

[@kensmechanicalaffair]

You still need to be able to diagnose it correctly.

[@brianmott728]

How do you determine if the check valve is good or bad? My string trimmer smokes alot all around the muffler. What does that mean? I'm putting the correct fuel mixture in the engine.

[@stevecollins1506]

the video show how to check the check valve bubba and it sounds like you have too much oil in your gas, pull the muffler off and look to see if its gummed up and that will tell you if you have been running too much oil in it

[@brianmott728]

The carburetor on my McCulloch string trimmer does not have a check valve like the carburetor in your video. I removed the muffler and it is not gummed up anywhere but I thoroughly wiped it off but it is not smoking excessively anymore.

[@philliphall5198]

Time and lack of knowledge to repair, check valves go bad from air psi

[@MetalMasterdom]

Bullshit. I've never seen a check valve go bad. It's called carb cleaner. Use it.

[@kensmechanicalaffair]

Carb cleaners will cause it to go bad, it's a common failure on a old two stroke.