Walbro HDC Carburetor...EASY Check Valve Test!

[@edm5477]

If you remove the snap ring and the screen, a new check valve can easily be made from a spare piece of 0.2 mm thick carb diaphragm from a rebuild kit. The check valve is about the same size as the seat diameter of the brass insert. While it varies by carb, usually a 3/16" punch works fine. The replacement check valve can be gently worked into the opening using a blunt tip dental pick. Once it's inside the hole, it will flatten out and center itself. Then just replace the screen and snap ring and reinstall a new Welch plug (if one was present). I was working on a saw which had very erratic behavior - uneven idle, inconsistent high speed performance, racing idle and stalling out. I had already rebuilt the carb, so I thought it was an air leak. After a massive headache and many wasted hours, I eventually traced it to the check valve - which was missing entirely in this particular carb. Replaced the check valve and it ran perfectly.

[@bonzaibarty]

thank you very much for explaining the function, operation and testing of the check valve! my hdc was pooring fuel out of carb there was no check valve diaphragm at all and no screen!!!

[@G-PA-2795]

Very good tech tip. I'll try and store that one in the old brain. Thanks Leon

[@leehotspur9679]

Thanks for sharing you skills Much appreciated

[@eagleeyeswings2863]

very good demo sir ! camera view 10/10

[@jeffblack1644]

Thanks for explaining this!

[@Bill-xc8le]

I live where that Walbro Carb was made. Years ago if you new somebody that worked their, and if you had a bad Carb you could have them take it to work, and they could have it rebuilt just like it was new off the line!

[@seriksson9721]

Ingenious and wise way of working, thank you very much.

[@jimball816]

another great vid. you answer at least 10 of my questions as to function, repair & parts. extremely helpful

[@marksarkaquariums9056]

Great Video.I rebuilt a HDC last yr and I used a oregon kit.I think it came with the mini diaphragm.I'm going to check the bag today.I always put all the parts I swap out back in the bag.Thank's for sharing all the Great tips Leon.

[@jeffvickers733]

Thanks Leon, your a reservoir of knowledge. The shade tree chainsaw community thanks you! Hope all is well, God bless you and yours.

[@bonzaibarty]

Great information!! Thank you very much!

[@joew9392]

Thanks! I've been hoping to find someone who knew how to test those check valves. I have a few of the HDC carbs, I'll use the good ones and use the others for parts. Again, thanks!

[@hiphopman72]

Sounds like my issue with the old Mac 30 … I need some Welch now. Thanks

[@Bob-ux8sn]

Thanks Leon Great information

[@tomalophicon]

I have a Husky 365 that won't idle but will start perfectly every time. It'll rev up when you tickle the throttle. The check valve (or main nozzle) is totally free to suck and blow both ways. Will be ordering a new one. Thanks for the great video.

[@jdprice3043]

Thank YOU FOR YOUR HELP

[@jamesfarley5183]

Love your vid Leon. they are great . the hi ck valve lets all the hi speed fuel into carb. and stops all/most of air press. 14.7 from from going back into metering area preventing diaph. from pull down and opening needle valve ,ie no fuel and starvation but mostly @ idle /lo speed starve out shortly after return to idle. bad gummy ck valve plugs hi jet fuel out . can be ckecked w wac/press gauge w carb fully assembled. conn. and pressure inlet hose to 7 psi and depress metering diaph. .if press, immediatly goes out several pumps outlet hi jet is open. if not jet is restricted . then apply vac w diaph . down to open needle valve again should pull down w slight leakage due to idle jet air intake. if a purge bulb is on saw use the purge nipple w/out depressing diaph. purge bulb won't work right w bad hi ck.valve. as excess air into metering chamber from def. hi ck.won't draw fuel from tank.

[@Countrysawshop21]

Thank ya Sir!! This i needed to know and you covered it well. Very informative.

[@geofgladman440]

Great video.

[@elioselectric468]

Great tip Leon, thanks

[@Indeewoods]

Right on good tip. I noticed on my XL-1 Auto that high speed adjustment is acting just like you say "all over the place" I wonder if that's the check valve. I'll have to check that out.

[@simpleman4224]

Great info! Thanks for sharing!👍👍👍👍🇺🇸🇺🇸🇺🇸🇺🇸🙏🙏🙏🙏

[@brianperkins6121]

I have been told strong carburetor cleaner will damage the check valves due to it attacking the material they are made out of , I know from experience it can also impact the check valves in the primer housing on the Zama carbs used on mantis tillers, have you ever heard of issues where this has happened ? have had ethanol fuel issues with them as well..

[@chantzbirch1151]

Sweet tip!

[@AIainMConnachie]

Good old video. I usually don't horse around with these tiny check valves & Welch plugs anymore. Time is spent & money wasted. Most aftermarket carbs are decent enough quality now & inexpensive too. Cheers.

[@Roberttaylor-lf2rz]

Just found your site, and this is the closest I can find to my problem. I have a Stihl 015 saw with a Walbro HDC 17 carb. The saw is driving me crazy. It will start and run a little and than overload with fuel and fuel runs from the exhaust. I have tried to adjust the metering level and cannot figure out a factory position or starting point. I feel sure that I bent it someway when I was taking the carb apart to put new parts in. Is there a normal position that both ends of the lever should be set? If this is the wrong place for a question I apologize. Robert Taylor.

[@craigtimmons3468]

GREAT TIP👍

[@justinweaver8787]

Hey buddy I Know you have a lot going on and I truly hope the best for you and your family. I have a few saws I'd like to have u work ur magic on all homelites. One was my grandfather's saw I'd love to get running great again. If u have the time I'd love to email you and see what I should do next if u are to busy at this point I understand. Thank you for all you do. Love ur channel.

[@jamesfarley5183]

hi jet and ck .valve can be cked w mityvac on saw ,just be sure to dump all fuel from carb chamber .it's bad to mityvac on vac. use. to get gas in pump, but press. ok. hi/lo needles should be in norn adj. out ie. 1 1/2 turns.

[@TheWarjunkie666]

Your vids are immensely helpful, I was wondering if you could tell me if something is up with my hdc 44. So I've just rebuilt it and went to blow through the fuel inlet. Now on most carbs with a float you should be able to blow into the carb no problem while the float isn't pushing the needle into the seat. When I go to blow through the inlet on my hdc 44 it's rock solid.... Did I mess something up or is this normal?

[@carlodonnell146]

check the check-valve to be sure that the check-valve is checking, right?

[@keithm.9062]

I’ve got s Walbro WA-19 that won’t start after installing new gaskets & diaphragms. I tried the tube method to the check valve and it doesn’t close. Know how to remove it for replacement? I’ve emailed Walbro but no response so far.

[@scottcrowley2061]

I have an HDB that cuts off at high speed although a couple times recently has run correctly,one time seemingly pressurized the tank? it also has the brass screen in the center like the HDC

[@KensSmallEngineRepair]

Mityvac instead of mouth? I don’t know if I could trust my mouth! Great vid, thanks!

[@tomalophicon]

The Zama service manual recommends this mouth method.

[@KensSmallEngineRepair]

@@tomalophicon I prefer a constant source like the Mityvac

[@Indeewoods]

Working on a little XL and the check valve passed the test. Well I took the ring out and the screen and didn’t think I poked through but now it doesn’t seal. So dumb that they include all that and not the check valve. This check valve disk seems hard and thicker than diaphram material but maybe that’s just because it’s old and brittle. Going to write into walbro and ask them why the heck they can’t just throw that in the kit. Frustrating.

[@Tysman909]

Can the shaft be taken out of an super ez carb and swapped with one from an xl2 or super 2? The carbs look identical except for choke shaft

[@gamerX-wk7ct]

I'm sure you got your answere by now I would say yes you can but not sure so did you ever find out if it will fit

[@Tysman909]

@@gamerX-wk7ct never tried if the diameter of the shaft is same it should fit

[@georgebacchas2633]

Needs to zoom, fighting to see what u r saying

[@jerrysoutherland662]

Would you be better off,in buying a. new carburetor,just saying.

[@gamerX-wk7ct]

I know this is old but no buying a new carb wanted be smart when the old carb is fine just fixed plus alot of these carbs are not being made

[@jeffreylangenstein4222]

Great tip Leon ,Thank you