147 MG Tech | Carburetor Tuning

Silent tune up of Carburetter

[@casualcombine]

12 years later, this still helps! Thank you!

[@canalucareestesianumeameu344]

Thank you sir. I could listen to you all day long.

[@tuxdrummer]

This is the best SU carb tuning video I've seen yet. Thank you for approaching it like an engineer!

[@foundonly]

Thanks John, explained beautifully and without fuss.

[@NZbird]

John, I know that this is an old video but I bought a '72 BGT late last year and today, I set the carbs up as per your instructions. So easy to follow and boy, it's like a different car. Many thanks indeed. Geoff in NZ

[@mgbsandotherstuff2982]

Love everything about your channel, I have a 63 MGB and really appreciate your informative videos. Cheers.

[@Unorthatrox]

This may just be the only video I've ever come across with only thumbs up and not a single dislike, and for good reason. Im completely new to these carbs and I feel like a pro already. Thank you.

[@benrobertson7855]

Just amazing.cant thankyou enough.so hard to find such clear information,here in n.z far north. so very much appreciated,have a 1500 spitfire as the daily runner.so much information ,so clearly put. Thanks again.

[@reinhardtrippmacher8776]

Thank you so much Sir. Very professional explained. This gave me a lot of new hints. Especially the "reng reng" in between seems more important than I thought. My guys in the garage always look at me as I wanna show off when I do that...now I can explain them why!

[@Matbug1812]

Super valuable information, very well explained! Thank's John, love ur videos!

[@darrylyoes414]

Brilliantly done! Thank you.

[@Kieran46100]

great video, thanks a million for you generosity

[@slyanca]

Great Joh, I just inherited my fathers MGB and compared to my 1957 Chevy 210 it is a mystery.. This video help me enormously. Now I just need to find a passenger side floor pan.

[@riz2337]

Your instructional videos are greatly appreciated...thanks so much for making them. I hope someday to visit university motors.

[@flon4602]

Fab video- good engine noise- you are a star, thank you

[@My72MGB]

New MGB owner here, I don't know much about carps but thanks to u I know just a little more!

[@bisonuberti]

Wow... you make it sound and look easy. Thank you.

[@mtyquinn6]

Thank you John! I have been putting this off and driving a very outta tune car for over a year. I tackled this and cleaned up the carbs (on the car) in an hour... You give great details and hints. Still not 100% on the mixture (maybe I am lifting too much (tried the lifters and your screwdriver method). I get a rough condition when I lift 1/4" (about what the lift rod give it). I think you said this is a lean condition - so I backed out the mixture nut. (1966 Sprite with SU H2 carbs). Total timing is 32 (with vacuum off and plugged). compression is equal on all pistons. Spark plugs are what you recommend Champion N9Y. She runs 1000 percent better and starts with a bump of the key - cold or hot (I hatted starting it in a parking lot after talking to people about it - because it never started well.

[@seans_shed]

So we’ll explained. Made it simple to understand and a lot of useful info, thanks a lot 👍🏻

[@phillsmith1901]

Brilliant, very well explained. Thank you

[@Turboboob]

Very nicely done, thank you soo much. Very much appreciated.

[@Tubecraft1]

Very good clear video thank you. Wish I worked in your shop.

[@palfab962ify]

Excellent as usual....thks

[@wouterlubbers]

thank you from Holland

[@TomRymes]

John and Co.: All of your SU videos show tuning HIF carbs. A demonstration on HS carbs would be great, too, especially showing operation of the jet adjustment nut, which way is lean, which way is rich, etc. Thank you for the great videos!

[@prostreetgsxr]

Great video bud!

[@nrw34260]

Excellent, Thank You.

[@pedrotalavera3541]

Great video. Thanks

[@DCuzick]

very good, thank you for posting this video.

[@thomasobrien3864]

Really good information worth saving

[@wallisparnell4464]

Just adding back HIFs to my 72 B, unsure on the throttle connection from under the SUs and the plate connection. Be nice to have a video on how to install the HIFs, thanks! Live your videos, makes my education excellent.

[@caddypaddy13]

Great help..

[@jameswyburd]

Thanks so much for this great video. I'm a 70 year Brit who's just bought a 65 MGB and whose mechanical knowledge doesn't go much beyond a paper clip. Yet following your video, I've managed to balance the HS4 SUs (using a hose with a funnel as an earpiece to balance the hiss). The front throttle screw is undone a bit more than the rear one, which I put down to wear & tear in an old car.

[@hughbriggs5440]

I dont mean to be offtopic but does anyone know of a tool to get back into an instagram account?? I was stupid lost the login password. I appreciate any tips you can give me.

[@stetsonbrett5912]

@Hugh Briggs Instablaster ;)

[@hughbriggs5440]

@Stetson Brett I really appreciate your reply. I found the site through google and im trying it out now. Seems to take quite some time so I will get back to you later when my account password hopefully is recovered.

[@hughbriggs5440]

@Stetson Brett it did the trick and I finally got access to my account again. Im so happy! Thank you so much, you saved my ass :D

[@stetsonbrett5912]

@Hugh Briggs Glad I could help xD

[@petereastey5909]

Well, well, well. G'day from Sunny Queensland Australia. I would like to thank you for your informative videos. I have a 79B that is running HIF SU"s. I bought the car some 15 years ago from a friend, who knew bugger all about it. On investigation I found that is an american import. I was told that by another fellow who also owns a G, way earlier though. " oh look it's got three wipers, an american import". hows that for investigation, ahahaha. Unfortunately for me though the carbs are not set up correctly and a few parts are missing and hoses disconected. It had run OK since I bought it but recently its been flooding the engine cyclinders with fuel. They are currently with a mechanic of some 40 years being cleaned and rebuilt...watching your videos shoows me where the previuos people have gone wrong and I thank you. yours Peter Eastey

[@edwardkendall3905]

First class instruction.

[@AndyHernandez-oh7fl]

thanks for the information

[@7thwilliams]

Weldone John, very interesting coverage, Pls can you make another vedio coverage on an HS CarbI have a 1971 MGB Roadster UK specThanks

[@hpeman321]

excellent

[@Jaytheozzi]

very informative video

[@CaptainCheezmo]

I might not have an MG, but I've got a '73 Volvo 142 with dual SU carbs on a B20B engine, and I've been needing to tune them up for a good while. Might just have what I need now to get them tuned! :)

[@bugeyev8]

I like how you use a fender cover...nice

[@5556ranger]

Thanks John

[@leeambrose4327]

Thanks for the great info. Are you in Canada by chance? I would love you to look at my MGB 1974. Out of nowhere the car has started to run rough and extremely rich. It’s a 1.8l 4 cyl. I had a local shop rebuild both carbs. It has stopped gas from pouring out of the charcoal filter but it will still stall at idle which is 1400 RPM. Once driving it works better. The shop says that as low as they could get it and they assume an intake manifold is causing a vac leak. After watching this video I did everything you said except sync the vacuum as I don’t have the tool. I was able to lean it out and get it to idle better. I thought it was good until the next night when I cold started it. I had to pour in a little gas into each carb just to get it started . Once started I adjusted the fuel to a more rich state and increased the idle. It now runs rich but at least doesn’t stall once it’s warm. I know this is a simple fix . I just paid $900 to have both carbs rebuilt but I doubt they synced or balanced them properly. Let me where your shop is located Or maybe I can send you a video of how it’s acting? Much appreciated

[@carlodangelo6437]

John, excellent tutorial- wouldn't a twinmax balance these carbs more efficiently ?

[@CaptainCheezmo]

@losmorob I believe it's near redline for checking mechanical advance. Could be wrong, might just need to keep increasing rpm until advance stops.

[@lancec6497]

Awesome! Thanks John!!

[@LeRoiDelaRue]

I have an MG ZT 260 for daily use and would love another B for every day use too

[@gfurstnsu]

Yes, I do not know why he did not state this. You must unlooses the nuts that clamp to the link bar. You cannot balance the carbs if you do not do this. Use a 5/16 inch wrench. Then tighten the clamps after balancing both carbs

[@nickb2833]

Nice hat mate.

[@Wiredeclipse]

Very Very nice info! I'm going to search your videos to see if you have one like this for the 1500 with a Weber 32/36 DGEV conversion. If you don't have one, could you please make one for the Midget if and when you come across one? Thank you.

[@allenhanford]

Great video as usual but is there one for the carbs on my 68 midget? Mine doesn't have a mixture adjustment like that.

[@austinwagoncompany]

Is there a base setting for the fuel screws? Like on other carbs.....screw it in back so much out just to get a good start. I have a rough idle at low rpm and it is running rich. I try to lean it out and it backfires.

[@michaelgoddard1435]

saved me $200 bucks from the mechanic down the street and took 12 minutes... excellent!

[@ColdWarVet607]

This is really great, thank you but what year, model, engine, carb are you working on? I'm going to help a friend get his 1962 MGA 1600 running, this looks similar to a point and I know in general these principles can carry over, but it would be nice to have a frame of reference. I've never touched an MG before, I'm all 50's, 60's 70's USA hot rods. But I am half a Brit by birth so I should know this stuff inside out. Thanks!

[@paulritchie1366]

great video but I found the quantity and viscosity of the oil in the dash pot cylinder was critical. I wondered why I could not achieve a correct acceleration performance and found the oil was very low and if filled , the fluffing issues were cured. The oil dampened the piton rise keeping it rich for a split second.

[@turbo3492]

The recommended oil for the SU dash pots is 20w50 engine oil.If you put a lighter weight oil in,the damper pistons will float instead of closing when they need to.

[@nosay2930]

This is a great video, but this is a US version off the car with all that added emission stuff. I like the screw driver tip, so much easier than using the lift pins

[@ricardosalinas2396]

Would you please make a video of a 175 cd2 carb and explain what each part is and does.

[@Unorthatrox]

Im having trouble with my rear carb. It seems no matter what position the mixture screw is in, i get the small rise in rpm, then a stall. The front I have no problems with

[@robinredbreast8292]

32 degrees needs a bit more clarity otherwise some may set their timing to 32 degrees btdc ! Instead of 32 max advance and 13 btdc.

[@Junhung90]

very informative video (Y)

[@nzsaltflatsracer8054]

Something you missed here is to verify the pistons move freely through full distance. Unscrew the dampers & raise the pistons by hand to verify this. You should also hear them hit the bottom stop to be sure they are completely closing. Make sure you have adequate oil level in the dampers or the pistons will flutter & rise too fast at throttle up. If you haven't already, you might want to educate people on the starting procedure for SU equipped vehicles, I have to enlighten nearly every customer I have to not pump the gas pedal. It saddens me to see all these cars here in the US without their SU's or CD's, they're great carbs when they are set up right.

[@bloodreighn]

Hey Maybe you can help, when lifting the piston do you only lift it up 1/32 temporarily or hold it there to check the mixture? also, on my car i lift and hold the piston but it dies immediatly when the mix screw is out 2 turns, the only way it rises and falls properly is almost out at 13 turns but this causes the plugs to foul badly, am i doing it wrong? ( Brand new HS4 with abx needle on a series 998 )

[@discountwise]

Hi John , I have a 1975 MGB with twin SU HIF carbs and I cant adjust them out of lean . When I lift the piston on them the rev drops no matter How the mixture is adjusted. Any help would be appreciated. Thanks Phil (Ireland)

[@neilshovlin9888]

The anti-run-on valve, the hose to the intake manifold... That plug/inlet/connection on the manifold... Pls. where did you get that...? Moss, etc., who..l please... ?

[@allenhanford]

When I try to use the uni-syn on my 68 midget the rpms drop off until I can't get a reading.

[@wallisparnell4464]

Need help on how to connect the choke cable to the HIFs

[@0liball]

Hi John, just wondering why you recommend avoiding iridium spark plugs?

[@jonathan99786]

What about the late MG Midget carburatos?

[@cyrussataravalla6731]

Ma786sai Dua are these SU the very same as on my 1982Rolls-Royce silver Spirit Mark 1?

[@jbstepchild]

Is all thus done on a cold engine or a warm engine

[@mamonki1387]

Magnífica explicación, la tendrás en Español ? Gracias

[@bernardwarr4187]

De donde eres ?

[@tomsgmail8180]

Hi John, Should one loosen the link bar between the two carbs before adjust them (so each can then be changed without effecting the other), then set the richness for each (which will effect the airflow, so done before balancing), before finally balancing the them?

[@gfurstnsu]

@@duaneriggs-long572Yes you must loosen both clamps on the bar that links the two carbs. This must be done before balancing the two carbs. After they both have the same amount of air intake, then you can tighten the clamps. If you do not do this, it is impossible to balance the carbs. What I do is before loosening the clamps, I use the unisynk tool to test if the carbs are balanced. If they are balanced, ie. Each I has the same amount of air passing into the engine, you do not have to loosen the linkage, your carbs are balanced. I have owned my ‘73 B since 1990 and do this exercise every year after setting the valve clearances.

[@pyroboobysmith359]

One very important step before any of this is relevant, is your float bowl fuel level must be set correctly.

[@12345694044]

At 7.00 it's the mixture screw,not Idle.

[@gfurstnsu]

Each carb on the HIFs has a mixture screw. This screw is hard to see as it is near the different lines to the carb and can be reached only with the air filters are removed on the stock carb is they are the original ones. The mixture screw moves the jet head up and down. If you move the jet up by turning the adjustment screw counterclockwise, you lean out the fuel mixture. Turn the screw clockwise and you enrich the fuel mixture. You can push the piston up and see the top of the jet. This is a way to visually check the location of the top of the jet. It should neither be too high or two low. I always start adjusting the carbs by putting this jet flush with the carb body then lower it slightly. Never start adjusting the carb without knowing where the carb jet is when you start. This is the mistake many make!

[@bishop044]

LOL , I watched this for 5 minutes before realising those carbs are HiFs whereas the MGB I'm working on is fitted with HS carbs :)

[@AJ-yo7rb]

First guy I’ve ever heard say 10 hundred..except me

[@Homebrew58]

You loosen the linkage when adjusting the air draw so you are adjusting each one independently don't you?

[@davidgambuto7743]

Homebrew58 h

[@gfurstnsu]

You must loosen the screws one of the linkage between the carbs before equalizing the airflow. Do not unscrew both linkages. Once you equalize the airflow then you tighten the linkage. I do one know why this is not included here. If you do not loosen the linkage, both carbs will never be able to be adjusted INDEPENDENTLY. After equalizing the air flow, then retighten the linkage on the one you loosened. Also make sure the the angle of the linkage is correct. Look at the owners manual to shop manual to confirm the linkage is at the right angle.

[@Scruit]

There's two idle adjuster screws per carb? One at 4:06 and one at 6:35

[@arnoldfinkelstein7156]

Are. There ARE.

[@flumpaustin1994]

I think he made a mistake. He meant "mixture" screw the 2nd time.

[@garyowen9044]

God bless all of you, they just don’t make enough Ritalin for me to do this.

[@edhaskell1554]

Where's the audio???

[@elliottbran]

I couldn't catch the name of the tool to check the air flow. Where can I get one?

[@brandongoins1919]

unisyn

[@elliottbran]

@@brandongoins1919 thanks Brandon!

[@craigpennington1251]

Love the video but I had my stuff all the way up and could just hear you. I got most of it. Volume is needed badly.

[@daveextra]

incorrect sorry but good effort. time served, factory apprentice england

[@flumpaustin1994]

Can you be a bit more explicit?

[@neilshovlin9888]

Don't you have to decouple the two carbs before using the Uni-syn... You do each one, than reconnect them... That's what I'm told... ?

[@MrSevenup89]

I wonder...bad carburation..let also car not to take enough gas and start muttering? That's my case. Fuel consumption is high. 15 km with 1/4 of the tank.

[@palmpje5]

zit ik erop te wachten hoe dat mooie metertje werkt voor de carbarateur ,,omdat ik ook zo,n 1 heb maar ik weet niet hoe ik het moet doen.jammer

[@paulhotson5820]

Tune using your ears lol.

[@barnaba1964]

was better the webers double body....

[@jasonmessick4689]

Ugh

[@verygood7155]

Ever heard of using a fender protection pad or towel? Some pathetic mechanics like this guy don't give a crap how much they scratch up their customers paint jobs.

[@fredyellowsnow7492]

Notice, the other cars in the shop have wing (proper word for it on a British car) protection, so maybe this is an old heap that doesn't even run and is due a total rebuild and paint anyway, so who cares?