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CARB SETTING

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digcot65
Posts: 57
Joined: Mon Aug 02, 2021 10:01 am
Location: bromsgrove uk

CARB SETTING

Post by digcot65 »

Morning I finally have the car running well and am about to set carbs up .Im waiting for a balancer,as the one I have will not fit between carb and wing. The carbs are seperated at the moment ,but I was wondering how the "cold start" screw is adjusted as can be seen in the photo . I ca`t seem to find details in the workshop manual Also,does anyone know how much petrol is left in the tank when you have to switch to reserve Ive rebuilt the reserve switch with new seals,but when I switched over to reserve while setting the car up,it ran out of petrol and Im wondering if the reserve switch is working correctly Len
Sorry photo is a bit blurred using my wifes camera
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Brian-H
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Posts: 720
Joined: Fri Aug 09, 2019 6:04 pm
Location: Loughborough

Re: CARB SETTING

Post by Brian-H »

I can't help with the "cold start" screw , but the reserve level in the tank is supposedly 1 gallon. But like you, I've noticed that when tinkering it doesn't last long. When driving the car, as soon as you pull the reserve, you should put more fuel in at the next garage and not rely on 20 miles (at 20 mpg).

digcot65
Posts: 57
Joined: Mon Aug 02, 2021 10:01 am
Location: bromsgrove uk

Re: CARB SETTING

Post by digcot65 »

Thanks that has helped a lot.If you imagine,one gallon spread over the area of the floor of the tank,it would amount to very little. I found that after I switched to reserve in no time with the tinkering about,I ran out of petrol Just waiting for a balancer to arrive,so I can set the carbs.the one I had use of,wouldnt fit between the carb and the wing ,on the front carb Len

HenryC
Posts: 294
Joined: Mon Feb 15, 2016 8:31 pm
Location: Surrey / East Hampshire

Re: CARB SETTING

Post by HenryC »

The adjusting of the Cold Start screw adjustment is given in Section D of the Service Manual on page 14 for the H6 carbs and on page 24 for the later HD6 carbs. It's purpose is solely to increase the throttle opening as the choke is operated, so the engine idles at slightly higher revs. This screw does not affect the mixture.

The enriching of the mixture using the choke is completely different on the two types of carbs. From the photo, you have the H6 carbs.

Email me through the forum or phone me if you would like to discuss this further.

According the the Service Manual the reserve fuel capacity is 1.5 gallons. When I replaced the corks seals in the fuel changeover switch, I found the cable needed careful adjustment to ensure that the plunger travelled equally in both directions to ensure that the port was fully open in each position. You may find that the reserve fuel pipe filter (in the tank) is blocked if it hasn't been used for a while.

Hope this helps.
Cheers, Henry Curwen
Registrar for Conquest & Century Saloons (DJ250/1, DJ256/7, DJ260/1)

Conquest (Drop Head) Coupe DJ252
EL24
MGB 8-)

digcot65
Posts: 57
Joined: Mon Aug 02, 2021 10:01 am
Location: bromsgrove uk

Re: CARB SETTING

Post by digcot65 »

Thanks again Len

JT7196
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Joined: Sat Feb 13, 2016 7:22 am

Re: CARB SETTING

Post by JT7196 »

Hi, talking about “How much fuel left in the tank”: well some time ago I managed to find a chap who was able to sort out my “ Sender Unit” ( now retired! ) into a working condition.
This week whilst fitting a new In-line fuel Filter and believing the the Petrol level was low in the Tank, the Gauge was reading around 2 gallons, so I decided that I would take the Bull by the Horns and drain the Tank to see just how much there really was in it.
Fortunately I had accumulated a number of 5 Ltr Oli Cans, I placed a large container under the Tank Drain and started to drain the Tank, I ended up filling up 4 Cans + a bit !!! .
I then re-placed it all back into the Tank , I then removed the “Sender Unit” and adjusted the Float operating Arm to reflect the Tank contents( Well damn near anyway ! )
At least I now have a pretty good idea what being registered on the Gauge, is more or less what’s in the Tank !👍👍

Cheers Al 👍👍👍

digcot65
Posts: 57
Joined: Mon Aug 02, 2021 10:01 am
Location: bromsgrove uk

Re: CARB SETTING

Post by digcot65 »

Morning I`m in the stage of setting the carbs up after rebuilding them. When I stripped them down,due to very poor running,there was about 5 mm of sludge in the bottom of each bowl I doubt if they had been remover for years and I was amazed the car ran at all When Im happy with the carb set up,I think I`ll drain the tank to see how much is in At the moment,I haven`t a clue as to whats in the tank, when I have to switch to reserve which is a bit off putting.I remember some time ago ,the gauge was showing 1/4 full,yet there wasn`t that much in the tank As usual there is always something to do owning a classic car Len

qantasqf1
Posts: 242
Joined: Mon Mar 07, 2016 10:13 pm

Re: CARB SETTING

Post by qantasqf1 »

To set the high speed idle with the engine on choke is pretty straightforward.
1)with the engine idling and the choke NOT operating set the correct idle speed using the normal adjusting screws in the usual way, making sure the two choke idling screws are clear of the carb. housing by unscrewing them until there is a definite clearance of approximately 0.015” between them and the housing.
2)Operate the choke and set the high speed idle using the choke adjusting screws. Hope this helps.
Steve

digcot65
Posts: 57
Joined: Mon Aug 02, 2021 10:01 am
Location: bromsgrove uk

Re: CARB SETTING

Post by digcot65 »

Thanks Len

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