803 Carb/Throttle spring positions

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George-Allen
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803 Carb/Throttle spring positions

Post by George-Allen »

I've reattached the SU carb to the manifold, all went well.
New problem... I can't for the life of me figure out where some of these springs hook up to.
One long spring is attached down low on the sidewall of the engine bay, don't know where it fixes to.
There's another shorter spring (maybe 5-7cm) on the forward side of the carb bowl on a rocking assembly, not sure where it goes either, but it looks like it needs to me angled down low towards something.
I'm new to this and am struggling to find any helpful sources that explain the spring set up.

Please help, I want the car running soon.
Cheers.
George.
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geoberni
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Re: 803 Carb/Throttle spring positions

Post by geoberni »

I think I know which springs you're talking about, but just to be certain, post up a photo of the carb and the springs dangling and I'm sure we can point out where you need to connect them.

A picture paints a 1000 words and such philosophical phrases....
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George-Allen
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Re: 803 Carb/Throttle spring positions

Post by George-Allen »

Here's both springs I can't figure out.
The long one attached to the wall is long enough to sit on the inside of the throttle assembly, I don't know about the short one though, absolutely lost with it.
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svenedin
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Re: 803 Carb/Throttle spring positions

Post by svenedin »

I don't know much about the 803cc A-series set up because I have a later 1098cc.

I think the 803cc had an SU H1 carburettor. Those 2 springs as far as I know are the choke return spring and the throttle return spring. In the later 1098cc the throttle return spring connects to a bracket that is attached to the exhaust manifold clamp and to the throttle lever on the carb. The smaller spring is probably the choke return spring and is designed to pull the jet assembly back in when the choke cable is pushed back into the dashboard. It will connect to the jet lever.

This diagram shows the small spring which is the choke return spring.

https://sucarb.co.uk/technical-h-type-c ... er-diagram




Stephen
1969 1098cc Convertible “Xavier” which I have owned since 1989.

Stephen
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Re: 803 Carb/Throttle spring positions

Post by jaekl »

Throttle return spring for that vintage most likely was attached to the air filter assembly.
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geoberni
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Re: 803 Carb/Throttle spring positions

Post by geoberni »

I must admit I don't recognise the springs that you have.
I agree with Stephen that the one fitted to the inner wing is in totally the wrong place, it appears to be the throttle return spring and is usually on a bracket on the Exhaust Clamp.
A Past Owner has probably lost the correct fitting, something like this.
Throttle spring.JPG
Throttle spring.JPG (39.93 KiB) Viewed 346 times
I've never seen such a long spring used for the Choke Return, but if they bodged one spring, who's to say they didn't bodge both.... :-?
That's the problem with these cats, people have had 75 years to fiddle with things....
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svenedin
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Re: 803 Carb/Throttle spring positions

Post by svenedin »

jaekl wrote: Thu Oct 31, 2024 11:00 am Throttle return spring for that vintage most likely was attached to the air filter assembly.
Yes that's possible but if you look at the linked picture it looks as if the throttle return spring needs to pull downwards as it does with the later carbs. As I say, my knowledge of this engine is very limited but I do know that it had a large air filter assembly above the engine.

Here is a picture of an SU H1. You can just see the choke return spring.

https://www.morrisminorspares.com/fuel- ... s-p1238995

Stephen
1969 1098cc Convertible “Xavier” which I have owned since 1989.

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geoberni
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Re: 803 Carb/Throttle spring positions

Post by geoberni »

Here's an image I lifted on line from an 803cc with Oil Bath Filter. No sign of a spring attached at the 'front' of the Carb, where OP has shown one :-(

I'm convinced it's a PO bodge, probably for the Choke Spring.
Throttle 2.JPG
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Basil the 1955 series II

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svenedin
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Re: 803 Carb/Throttle spring positions

Post by svenedin »

Yes the OP's choke return spring looks much too long compared to the diagram and picture of an H1 carburettor.

As for the throttle return spring, I think it hooks to the lowest part of the air filter assembly where the "shield" part of the assembly curves over and dives down over the carb.

Stephen
1969 1098cc Convertible “Xavier” which I have owned since 1989.

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geoberni
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Re: 803 Carb/Throttle spring positions

Post by geoberni »

svenedin wrote: Thu Oct 31, 2024 12:28 pm Yes the OP's choke return spring looks much too long compared to the diagram and picture of an H1 carburettor.

As for the throttle return spring, I think it hooks to the lowest part of the air filter assembly where the "shield" part of the assembly curves over and dives down over the carb.

Stephen
Yes, I've found this odd little bracket with a hole in it as part of the Filter Mounting assembly. I just can't find a decent photo online of that side of the engine/filter area... It would just seem to pull out as a bit of an angle.
Throttle 3.JPG
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MM1949
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Re: 803 Carb/Throttle spring positions

Post by MM1949 »

That looks like a H2 SU not a H1 that the op has...so the spring goes down on the bracket on the exhaust clamp as pointed out already...
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geoberni
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Re: 803 Carb/Throttle spring positions

Post by geoberni »

MM1949 wrote: Thu Oct 31, 2024 1:02 pm That looks like a H2 SU not a H1 that the op has...so the spring goes down on the bracket on the exhaust clamp as pointed out already...
I thought the HS2 Float Chamber had the 3 screw fixing, while the H1 had the single central Nut type?
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Re: 803 Carb/Throttle spring positions

Post by MM1949 »

948cc H2 or H2 body and H1 float chamberor 948cc H2 with 803cc float chamber top.... Frankenstein SU :) :) :) :)
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svenedin
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Re: 803 Carb/Throttle spring positions

Post by svenedin »

Yes but the H1 is a 1 1/8" inlet and the H2 is 1 1/4". They only really differ in the inlet size. They both have a float with a single central bolt unlike the HS types which have 3x machine screws in the float bowl lid.


https://www.morrisminorspares.com/fuel- ... s-p1238996
1969 1098cc Convertible “Xavier” which I have owned since 1989.

Stephen
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geoberni
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Re: 803 Carb/Throttle spring positions

Post by geoberni »

svenedin wrote: Thu Oct 31, 2024 6:47 pm Yes but the H1 is a 1 1/8" inlet and the H2 is 1 1/4". They only really differ in the inlet size. They both have a float with a single central bolt unlike the HS types which have 3x machine screws in the float bowl lid.


https://www.morrisminorspares.com/fuel- ... s-p1238996
I'm not that au-fait with identifying SU Carbs, my original Carb experience back in the day was Webber and Zenith, having the SU on the Minor was a new experience. Hence I can get the H2, HS2 etc a bit mixed up....
I just know that my Basil has an HS2 because of the AUD13 tag on it :wink:
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