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mikeh

Stromberg float setting

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Having rebuilt the Stromberg CD175s on my TR4, I’m struggling to sort out the correct setting for the float height. Looking at previous posts on the forum and on the internet, there seem to be various dimensions quoted and they look to vary dependent on the exact model number of the carb and also the type of float fitted.

 

I believe that the carbs I have are the originals - they have the reference number CD1825 and are fitted with ‘old-style’ solid black floats (not the newer white plastic type).

 

The Stanpart workshop manual shows a setting of 9/16” (see attached) while the Haynes manual (not always the most reliable I know!) says 18.5mm and the Zenith data sheet (see attached) says 11/16”.

 

To add to the confusion, while the workshop manual and Haynes book both show the same way of measuring this, the Zenith sheet states that the dimension given is the “fuel height” which of course could be interpreted as a different measurement altogether.

 

Hopefully there are some Stromberg experts out there who can advise and clear up the confusion for me.

 

Thanks

Mike

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Mike

I run Stromberg CD175s and like you , know that the info on Float heights is definitely "confusing ".

7 reference books / manuals + the Internet... later !!

The 11/16" fuel height equates to 17.5 mm. The range of " float " levels , for your solid floats from my reference sources is 18mm to 19.5 mm. Two are 18.5mm .....Haynes and Autobooks.

My suggestion is to use the 18.5 mm figure. ( The plastic hollow float heights are smaller , range of 16 to 18mm ).

 

I would love to know how on earth you would be able to measure the fuel height easily. Presumably , refit carbs to car ,turn over the engine to fill the float chambers. Remove float chamber, without spilling any petrol and measure top of chamber to fuel. Replace and do number two carb. Adjust gap as necessary and then repeat.

I trust you used rubber diaphragms suitable for modern unleaded fuel in the rebuild.

Good luck when you fire up the car again.

Bob

Edited by bob-menhennett

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MyTR4 factory manual shows 18.5mm or .730. I don't think it is super critical as long as the fuel isn't slobbering over the jet or too far below the jet. Usually, the only time the float height is checked is when the needle valve assembly is replaced. I got to admit the SU carbs are more convenient in this area, especially when dealing with a clogged needle valve on the roadside..

Berry

Edited by dingle

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Try giving Burlem Fuel Sytems a ring on 01722 412500 or email them at info@burlem.co.uk. I get all my Stromburg spares from them and they are very knowledgeable. I am sure they will be able to give you the correct figure.

 

Geoff

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Try giving Burlem Fuel Sytems a ring on 01722 412500 or email them at info@burlem.co.uk. I get all my Stromburg spares from them and they are very knowledgeable. I am sure they will be able to give you the correct figure.

 

Geoff

 

If that fails you could try Burlen. ;)

 

https://burlen.co.uk/

 

Cheers

Graeme

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Thanks for the various replies and I’d certainly agree that it’s far from straightforward to find a definitive answer. I’d also agree that it’s much easier to adjust the float height on SU’s!

 

I had spoken to Burlen and they provided me with the attached Zenith data sheet giving the 17.5mm (11/16”) ‘fuel height’ setting. This rather added to the confusion so I think another call to them is needed to try and clarify matters.

 

Mike

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I will add a little more confusion....

Stromberg 175CD2-SE - are set @ float level 16 - 17 mm.....

Regards

Jochem

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Edited by JochemsTR

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I've only had to reset mine once in 10 years after cleaning and + - 1mm won't make any difference at all. Just make sure the floats have no pinholes or any fuel inside them.

A weight difference or any stiffness on the pivots and they won't work.

Chris

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Thanks for the further comments.

 

A friend and fellow TR owner has sent me a page (attached) from Kas Kastner's book which has a section about Stromberg carbs. Interestingly, Kastner says that they are sensitive to float level and gives a table of values, the key one from my perspective being 17.5mm (11/16") for composition (solid) floats on CD175 carbs. He does say that this is as advised by "the folks at Stromberg" (i.e. Burlen) and it matches the figure they gave me when I spoke to them.

 

Quite where the ST workshop manual figure of 9/16" (14.3mm) comes from I'm now not sure, as I haven't been able to find it referenced anywhere else.

 

Mike

 

 

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Hi Malbaby,

 

Thanks for your note.

 

Yes, I've replaced the floats and needle valves (matching sets) and it's as a result of doing so that the question has arisen about what the float height should be. Prior to replacing them, the floats (black composition type) were in a poor state and the needle valves could easily be persuaded to stick.

 

Given that Kastner & Burlen are in agreement on 11/16" / 17.5mm, I'm inclined to go with that figure and see how I get on.

 

Mike

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Just as a follow-up to the original post, I have now stripped down the carbs to check/sort this.

 

I found that the floats were slightly out, by about 2mm, i.e. a setting of 19.5mm when measured in the stated manner. I therefore reset them to the Kastner/Burlen recommended figure of 17.5mm and this has made a huge improvement. It's eliminated the hesitancy which I'd otherwise been unable to solve and the carbs are now set just a flat or two from the recommended start point of three complete turns down, whereas previously they had to be more than a full turn lower (richer) to get any sort of reasonable running.

 

Kastner does say in his book that Strombergs are very sensitive to float height setting but, prior to this, I certainly hadn't appreciated just how much difference a couple of mm could make.

 

Regards

Mike

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