Concentric carb level far too low???

[KEES_MATCHLESS]

Hello good afternoon, I have a question about the correct petrol level of my concentric 626 Carburetor. I bought this carb new, but I think the level is not correct. It was difficult for me to find the correct way to check that, anyhow I think I have found it. The correct level is between 4,33 and 6,35 mm below top edge of the carb bowl, 0,21" plus / minus 0,04 inch.

Referring to the attached image, should I measure as pictured by the red arrow? If so then it looks like the level is far too low, the level I measure is between 10 and 11 millimeter. In this case I would not expect that the motor G3LS 53' will run at all, but it starts, when warm it runs up and down when idling.

Another thing is that the carburetor is not horizontal when standing straight, the end of the carb is higher than the manifold. Is that normal?

Regards Kees

[Mick D]

Hi Kees

I'd agree with your findings based on your measurements, it does seem a little low - where did you find the data for the fuel level in a Mk 1 concentric?

The originally fitted Monobloc would have been slightly angled up as you have observed and I don't think this is worthy of concern when it is replaced with a Concentric, though if you're bothered you could tailor the insulator and fixing holes on the carb to allow it to fit horizontally.

Regards Mick

[KEES_MATCHLESS]

Hi Mick thnx for the response. I used the following site http://amalcarb.co.uk/optimising-mark-1 ... uel-levels, which is full of technical information about the Amal carburetor.

I will change the level according to this, but leave the angle as it is.

Kind regards

[56G80S]

Different size engine but my G80S had a MkI concentric and ran fine until it was worn out and I fitted a Monobloc.

I wouldn't worry about the angle.

JohnnyB

[KEES_MATCHLESS]

Hi there,

Just to inform people how to measure the float level, at least as far as I know now. The measurement of my picture is wrong, if I understand another website then the tube should be at the motor end of the carburetor, not on the right side of the carburetor. Since the carb is angled and lower at the motor end this measurement will be less then on the right side.

https://www.classicbritishspares.com/bl ... oat-height


This week I will try to measure again and update the picture.

Regards Kees