SU carb flooding
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bill heywood
- Posts: 6
- Joined: Sat Dec 03, 2011 7:41 pm
SU carb flooding
I have a 1923 Rover Clegg 12HP Tourer which has a problem with the carburetor flooding and would be grateful for any advice on how to set up the carb which is an SU sloper unit
Re: SU carb flooding
Bill,
No experience of a sloper SU, but the float chamber is surely much as later types?
My general rule of thumb is that the level in a full float chamber should be sufficient to guarantee the correct height in the main jet - too low and the main jet supplies weak mixture, too high and it supplies rich (or even seeps in to the carb throat.
Again, as a general rule, SU suggest checking float arm/needle settings by taking the chamber top and holding it upside down so the float arm rests on the needle. For 1 7/8" & 2 1/4" outside diameter float chambers, you should be able to slip a 7/16" diameter rod (drill bit shank) under the forks of the float arm against the flat chamber lid face.
Check your float for porosity - pressed under the surface of hot water, do you get a stream of bubbles? I assume you've shaken the float to check it is empty?
No experience of a sloper SU, but the float chamber is surely much as later types?
My general rule of thumb is that the level in a full float chamber should be sufficient to guarantee the correct height in the main jet - too low and the main jet supplies weak mixture, too high and it supplies rich (or even seeps in to the carb throat.
Again, as a general rule, SU suggest checking float arm/needle settings by taking the chamber top and holding it upside down so the float arm rests on the needle. For 1 7/8" & 2 1/4" outside diameter float chambers, you should be able to slip a 7/16" diameter rod (drill bit shank) under the forks of the float arm against the flat chamber lid face.
Check your float for porosity - pressed under the surface of hot water, do you get a stream of bubbles? I assume you've shaken the float to check it is empty?
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bill heywood
- Posts: 6
- Joined: Sat Dec 03, 2011 7:41 pm
Re: SU carb flooding
The Su sloper carb is a bottom entry fuel supply. I have checked the float and this appears OK.
Re: SU carb flooding
Hi Bill
Have you checked with Martin Gee?
Mike
Have you checked with Martin Gee?
Mike
Re: SU carb flooding
Bill,
Researching via the Net shows that the early sloper carbs' float level was regulated by a leather bellows, but later versions (courtesy of Morris Motors) used a brass float with a bottom, attached float needle. (There is a video sequence on You Tube demonstrating adjustment). The needle is pressed shut by a flat tang - apparently adjusted in similar fashion to the top entry fork. Burlen Fuel Systems appear to have comprehensive info on all SU carbs and the ability to completely refurbish any SU carb.
Researching via the Net shows that the early sloper carbs' float level was regulated by a leather bellows, but later versions (courtesy of Morris Motors) used a brass float with a bottom, attached float needle. (There is a video sequence on You Tube demonstrating adjustment). The needle is pressed shut by a flat tang - apparently adjusted in similar fashion to the top entry fork. Burlen Fuel Systems appear to have comprehensive info on all SU carbs and the ability to completely refurbish any SU carb.