CHAINSAW CARBURETOR DIAPHRAGM: 'Metering Diaphragm' EPIC Function!

[@TheRepairSpecialist]

All Episodes -for 2-Stroke Carburetors Here. Thanks. Craig: kzbin.info/aero/PLrlXp3PlwgRI5OLvm3P91LJr1CYnO5TRD

[@shaggyda2758]

This is 'by-far', the best explanation & Video that I have watched on 2 stroke carburetors! Thank-You very much for taking the time to do this.

[@davorperovicful]

As a person who stayed away from mechanical work for most of my life I would like to thanks you for this outstanding video explenation. It's by far the best video explanation that I have seen on this subject on KZbin. Thank you, hvala! 👨‍🎓😍.

[@mowtoegee7049]

I've watched a number of your videos now and I'm learning so much. They are so well explained with the diagrams I use 2 stroke equipment every day for work and at home on the weekends. These old 2 stroke machines are fantastic but so many of them end up on the scrap heap probably way before they need to...

[@TheRepairSpecialist]

Thank you for your feedback. I really appreciate it. Craig

[@pollymnbvc]

Just top class instruction - wish I had had a teacher like you!

[@TheRepairSpecialist]

Thank you so much for your nice feedback. It's comments like yours that motivate me to continue making these videos. Craig 😀👍

[@siskiyouwoodsman4279]

Absolute best graphic explanation of two stoke carb operation I’ve ever seen👏👍 Thank You!!

[@TheRepairSpecialist]

Thank you so much for this really nice feedback. I really appreciate it. Craig

[@joeyshoe9095]

This is the best explanation I have seen to explain Metering Diaphragm Carburetors for 2 cycle engines. Most people I deal with just toss them out and buy a new one without ever learning the basics of its operation.

[@briang4470]

The main reason for that is because usually just replacing the diaphragm or carb kit doesnt fix them, it's usually a faulty check valve or small passage under one of the Welsh plugs is blocked and if you have those problems it costs more to fix that carb than it does to just buy a new one and it saves alot of time especially of you have to take the carb apart multiple times, I have personally wasted hours of my life trying to fix these diaphragm carbs and usually after you spend hours and get no where you just get fed up and put new ones on. Go into any STIHL dealer and ask for a carb kit, they wont sell you one because the kit is like $19 dollars or they will sell you a brand new stihl carb for around 25 or just slightly more than a kit on most machines and you dont risk messing anything up. I personally dont even waste time trying to fix these carbs its 10,000 times easier to buy a new one and doesn't cost much more, even some of the Chinese replacement carbs are cheaper than a kit and I have used several with great success

[@johnc4352]

" ardened roobahh " : ). Thank you sir, your videos are by far, the best explanations of how these machines work!

[@tommywilliams8953]

Very well explained. Can you please explain EVERYTHING about life to me?

[@abdulrt1245]

great videos, and excellent explanation keep on.

[@TheRepairSpecialist]

Abu Mustafa, thank you for your positive feedback. I really do appreciate it

[@OtisPlunk]

Well Done!

[@trainwrekk9685]

What would happen if the metering diaphragm gets stiff or harden with age? What symptoms would be experienced when trying to start a chainsaw for example? Thanks for a great video.

[@gclaper1234]

Hi. You vids are so informative it's mind blowing. I have leant a lot. I have a question can a pressure or leak down test be done through the spark plug hole if the exhaust and carburetor hole are blocked off. Thanks Glenn

[@mikejudd7794]

Great explanation and very informational

[@GordMcknob]

Brilliant video !

[@fiddyfivecent6717]

This is a well done video on how things work on the fuel supply side of the carb. I have a question about what is going on with this diaphragm as the motor is running. If I understand what you have said, once the motor is running and a vacuum is created this diaphragm is then constantly forcing the metering needle open? or at least open when there is enough vacuum to activate the spring and open the metering needle. Or do I have this wrong and the diaphragm oscillate as it operates? Thanks for your help.

[@alfredpavels7059]

Very nice lecture!

[@JuiceBanger1]

Great stuff

[@devilsoffspring5519]

Thanks for the vid! Unfortunately, none of the gazillions of vids online (KZbin or others) explain what to do when everything in the carb seems to work just fine, and the engine starts and runs, but is still finicky as all heck. Pressure reg seems good, fuel pump works well, fast and slow fuel needles are adjusted, idle stop is set... Engine starts and runs well for a while, you use the saw (or whatever) for a while, then it acts up again. Man oh man are these little carbs a fiddly pain in the arse!

[@devilsoffspring5519]

@@dehoedisc7247 I have plenty of both imagination and mech experience, and have designed and built successfully running small combustion engines entirely from scratch. No need for the hostility. Anyway, when an engine 'seems to want to run', but is really an incessantly fiddly pain in the arse (which they frequently are), it's invariably a carburetion problem.

[@mattfrank5314]

did you try a different 2 cycle oil?

[@devilsoffspring5519]

@@mattfrank5314 Wasn't the oil, it was the carb, which I finally got sorted out nicely and the saw ran like a champ. I got a fair bit of work done with it, running perfectly, then the ignition module crapped out! I trashed the starter trying to get it to run again :)

[@japejapettaja6940]

Hi! Thanks for a very good explanation. I am currently trying to find out why my chainsaw makes the sparkplug wet every time I try to pull start. It does happen even without choke. I try to dry the plug and try again but it does not ignite because plug is instantly wet. Spark is okay. Can you help? is there some needle not properly seated and sealed?

[@TheRepairSpecialist]

It could be needle issues but i would personally start by resetting your chainsaw kzbin.info/www/bejne/bWXTanmCoq6eodk here is another one of my videos explaining how to reset your carburetor hope this helps you :) - Craig

[@blackjietv1789]

Thank you

[@TheRepairSpecialist]

You're welcome. Thanks. Craig

[@Okie-Tom]

Very good animation. Helps me learn how it all works. Thanks

[@piladuwamanagenaleenpiyana5341]

Good job thanks

[@TheRepairSpecialist]

Thank you for your positive feedback. I really appreciate it. Thanks again. Craig

[@damariekoemai7635]

Understood. Thanks.

[@Ducktruckful]

Hi I didn't see you mention the hi speed check valve? any reason why you didn't cover this?

[@VanyaD88]

I have the same question as another commenter here. When the engine is running is the metering needle constantly held open or does the needle repeatedly open and then fully close as the piston cycles?

[@Despelothier]

thank you ¡great!

[@Lovinflyindrones2022]

I have a question, I'm new to the small engine repair business I've been thinking that I need to buy me some testing equipment such as spark tester, leak down tester and I feel like the most important a tachometer possibly an echo pet 1000r or 1100 r. I've had several tell me it's just a waste of money and time and I really don't necessarily need any of it. I would just like to have a professional opinion as to what would be the best for me to do. Thanks for any advice you can give me!!!!

[@jamalgoldenfalcon5]

The top seal not where the primer bulb is but the seal on top of that is removed I basically will get more power ?

[@rollyramkissoon858]

Does the primer bulb remain with fuel after burning out excess fuel to store away.

[@adithyadammalapati1122]

Can u explain the overfual problem and solution

[@stealhty1]

My trimmer After start It idle fine, but when you squeeze the gas , the motor floods and shuts off ,,I happens to be spoiled dirt fuel from last season ,( watch for Ethanol)

[@Jaysmobiledetailn]

so question, my troybilt weed wacker primer bulb stays stuck in. When i press the primer bulb in it never pops back out. I have all new fuel lines and filter on it. Does this problem sound like my metering diaphragm is not working correctly?

[@yrulooknatme]

hello. I have a 4 cycle trimmer that is misses at open throttle.. if I back the throttle off a bit it smoothes out....or if I put the choke on a bit it smooths out a little too? It's a new carburetor and no adjustment on the high side. a barrel type on a troy bilt 575ec. was asking if I should adjust the diaphragm, or drill out a jet? to enrichen it? or do you think it may be another issue all together? Don't work on many 4 cycles and usually the only carb problems I've seen was bogdown not a miss? any impute on something like this?

[@T..C..M]

You have a fuel supply issue, the carburetor should be set fine from the factory (albeit a tad lean for emissions regulations) shooting some carburetor cleaner into the fuel inlet should clear out whatever gum or varnish or debris that is blocking your fuel flow. Also check for fuel line cracks and the fuel filter.

[@user-sb5ud7ek9c]

So, my metering needle is in two parts, the rubber is separate from the metal, is this a problem?

[@TheRepairSpecialist]

Yes, I would purchase a new needle if that's the case.

[@drvosecac_gradinar]

Very nice explanation. Thank you.

[@thomasgronek6469]

what's the difference between a primer bulb and a purge bulb ?

[@benconeuniforms]

A question if I may...I have a Ryobi trimmer, that I rebuilt the carb. I got it running, but not well, have to use ether to get it started. The fuel line going to the carb is solid with fuel, but the line leaving the carb going to the external primmer bulb gets air in it and lots of air in the primer bulb. It is like it is pulling air internally from inside the carburetor. Any idea what is going on here?

[@seniorjohnl]

Have you replaced the gasket and diaphram? they will get brittle and leak with age, air and fuel.

[@brianperkins6121]

There is a tiny check valve assembly not shown, its often pressed into in the carburetor body between the metering diaphragm and the inlet of the main jet and its not shown in the examples here, its there to prevent air from drawn back into the carburetor when the metering diaphragm is under vacuum when the primer bulb is operated if that check valve is faulty it will let air be pulled backwards down the main jet and you will get bubbles and some loss of priming suction on main fuel inlet . it will also make the carburetor not meter the fuel correctly in the midrange to high speed step..

[@movingupautodiagnostics8645]

Subscribed

[@ethancolaco5596]

i have a small engine with a WT997 i found that idle and low operation is fine but during the high carb operation it bogs down in and out until im full throttle and it dosent move.I opened up the carb and there is a deformity on the metering gasket caused by a clogged fuel cap.Could this be the reason it bogs on high ?

[@soplim8632]

Are you running this carb on an RC car?

[@thijs1538]

But why close that needle valve at all?

[@geojor]

if a 2 cycle carb doesn't have a primer bulb, how is fuel forced back to the tank ? ...please answer ...

[@nybergsgarage]

magic!

[@jamalgoldenfalcon5]

Is the restrictor located in the carburetor

[@TheRepairSpecialist]

What restictor do you mean?

[@jamalgoldenfalcon5]

That top seal in the video if I remove that I’ll get way more airflow which means more power

[@tomthompson7400]

very good ,,,

[@WV591]

Most knowledgeable on tube bar none. Those Metering Diaphragms can be hell if you don't get the exact replacement. if that diaphragm nipple is too long or too short the carb will never run right.

[@NICKBOND-se1bh]

my blower wont stay started when i tilt the blower so i can blow debris.

[@NICKBOND-se1bh]

it stays started until i tilt it than it bogs down

[@karbyde1]

I know you posted 8 months ago but, i'ts likely the fuel pickup hose in the tank, it should have a brass fittting at the end and needs to flex to stay in the bottom of the fuel tank. Good luck.

[@DougHinVA]

too detailed and wordy with a British accent.... an American needs a plain-spoken and correct fellow to skip detailed diagram and illustration and theory and principles.

[@knackersnathan5448]

Typical opinionated yank. Great explanation video.