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brass plugs in the side of SUs?

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brass plugs in the side of SUs?
#1
dburdicktr7 Douglas Burdick
Batesburg, SC, USA   USA
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I have an older pair of H4 SUs. There are brass plugs where it looks like the emissions hoses should hookup. They are on both carbs and appear to be solid, as in no hole in them at all. Why are they there, and how do I remove them? I'm putting these carbs on a '72 GT and I want to be able to use the emissions of the '72 with these carbs.


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Re: brass plugs in the side of SUs?
#2
B-racer Avatar
B-racer Jeff Schlemmer
Shakopee, MN, USA   USA
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1950 Willys Jeep Pickup "Ratrod"
1964 Land Rover Series IIA
1971 MG MGB
That's your throttle shaft.


jeff@advanceddistributors.com

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Re: brass plugs in the side of SUs?
#3
ghnl Avatar
ghnl Eric Russell
Mebane, NC, USA   USA
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1961 MG MGA "Calvin"
Throttle shafts. Open & close the throttle - you'll see them move.

No emissions provisions on H4 carbs - they were used on MGAs. For the MGB you might want to find a set of HS4s.


Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100



Edited 2 time(s). Last edit at 2024-04-26 08:01 AM by ghnl.

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Re: brass plugs in the side of SUs?
#4
smokey w Avatar
smokey w Silver Member Juri P
Toronto, ON, Canada   CAN
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1971 MG MGB
On a '72, you need connections on the carb body for the hoses from the front pushrod cover, pipes on the float bowl top to connect hoses across the firewall to the carbon canister, and pipes on the float chamber tops for the fuel lines..


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Re: brass plugs in the side of SUs?
#5
Rufus Avatar
Rufus Gold Member Harry Singleton
Deep in the East Texas Piney Woods, TX, USA   USA
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1967 MG MGB "The White Car"
1967 MG MGB GT Special "Rusty"
Gotta get up early in the morning to beat Jeff to it.
As Eric said, you may want to source a set of correct carburetters for your 72. The HIF would have been correct for that year, and they are set up for the cannister.
From what I've seen, the H4's are worth more $$$, but in less demand than the HIF. You may have success finding someone to trade with. But before you begin the trading/selling/buying process you may want to familiarize yourself a bit better with which parts cross over without re-working the entire system. The devil is in the details, and while the carbs from an MGA will certainly work on a BGT, you need to concern yourself with crankcase ventilation, fuel overflow/venting and of course air cleaners. Lots of variables to take into consideration before you bolt on new carburetters.
What happened to the original carburetters?

Have fun


If ignorance is bliss, I must be the happiest man alive!
Signed

RUFUS
67 Roadster


Member Services:
HS Carburetors www.mgexp.com
Restoration Services. Complete SU carburetor rebuilding services. Complete SU carburetor sets available for RB retro-fit. SU's bought, any condition. MGB's bought and sold. Performance consultation. Rufus-h@hotmail.com 214-686-8692
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Re: brass plugs in the side of SUs?
#6
riley1489 Avatar
riley1489 Gold Member Bruce H
Great White North, QC, Canada   CAN
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1953 Jaguar XK120
1959 Riley 1.5 "King George"
1973 MG MGB
Why are we discussing H type carburetters? confused smiley Clearly the set shown is HS type.

FWIW the early 1972 did come fitted with HS type, later model year were fitted with HIF type.

B


Life's most persistent and urgent question is, "What are you doing for others?"

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Re: brass plugs in the side of SUs?
#7
ghnl Avatar
ghnl Eric Russell
Mebane, NC, USA   USA
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1961 MG MGA "Calvin"
In reply to # 4789658 by riley1489 Why are we discussing H type carburetters? confused smiley Clearly the set shown is HS type.

Indeed that is true. I was going by what the OP typed into his post.

H4 carbs are MGA, HS4 are MGB. The picture clearly shows HS4 float bowl covers.

But the brass bit under discussion is still the throttle shaft.


Eric Russell ~ Mebane, NC
1961 MGA #61, 1981 Alfa Romeo GTV6, 1984 Alfa Romeo Spider, 1991 Honda ST1100

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Re: brass plugs in the side of SUs?
#8
Factor Avatar
Factor Steve Williams
Clayton, NC, USA   USA
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1964 MG MGB MkI
Looks like someone has rapping the crap out of that float chamber. I'd say a stuck float valve in the fall of 1983. It takes a trained eye winking smiley

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Re: brass plugs in the side of SUs?
#9
dburdicktr7 Douglas Burdick
Batesburg, SC, USA   USA
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Thanks all. Im going to rebuild the carbs that came with the car, as they have the hookups. Thanks for all of the response!


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Re: brass plugs in the side of SUs?
#10
bencii Silver Member Ben Colpitts
Eden Prairie, MN, USA   USA
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1966 MG MGB
1973 MG MGB
Good decision. The originals have a replaceable bush for the throttle shafts while the Hs4s required a specific and expensive reamer to replace the throttle bushes. Bruce H and others might have the bushes on hand. Buy the authentic Burlen SU rebuild kits. Many replace the poppet throttle plates with solid ones. Others with more knowledge can advise on the pros and cons of that.

In reply to # 4789698 by dburdicktr7 Thanks all. Im going to rebuild the carbs that came with the car, as they have the hookups. Thanks for all of the response!


Ben
1966 MGB Tourer
1973 MGB Tourer

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Re: brass plugs in the side of SUs?
#11
Rufus Avatar
Rufus Gold Member Harry Singleton
Deep in the East Texas Piney Woods, TX, USA   USA
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1967 MG MGB "The White Car"
1967 MG MGB GT Special "Rusty"
Doug, the HIF that you show appear to be very rebuildable. If I may offer a word or two of advice, buy the complete master rebuild kit from Burlen and in addition spend the extra $$$ on the stayup floats. Why are they so expensive??? Because they are worth it!. There are a couple of items to be particularly careful about, but I've been building lots of HIF's lately and they are very good carburetters, not to mention they are correct for your car.
Feel free to give me a call if I can help with the SU's.

Have fun


If ignorance is bliss, I must be the happiest man alive!
Signed

RUFUS
67 Roadster


Member Services:
HS Carburetors www.mgexp.com
Restoration Services. Complete SU carburetor rebuilding services. Complete SU carburetor sets available for RB retro-fit. SU's bought, any condition. MGB's bought and sold. Performance consultation. Rufus-h@hotmail.com 214-686-8692
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