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SU carb Help

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K

Ken791

Freshman Member
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I can not lean out my SU's on my 948cc frogeye.
The needle is the standard GG. Even with the mixture nut all the way up the carb still is rich and the car runs. I rebuilt the carb per a great video, just don't know where I went wrong. Anyone have any idea of would cause this rich condition?:mad-new:
 
Did you make sure that the jets are pushed all the way up? Sometimes they don't move all the way without a push on the bottom.
 
It is possible that your floats are too high and thus your fuel level is also high.
try bending the brackets a little to push the floats about 1/8" lower and see if that helps
BillM
 
Related question: Does the SU video cover the SU H1 carb as well as later ones? I used it once to rebuild my TR3 carbs, but I didn't notice if it covered the SU H1 ("Bugeye") carb, and I no longer have the video.

Many thanks.
 
I checked the float levels, they were spot on. Checked timing, spot on. Jets were all the way up. I am using the colour tune tool, am always getting a bright yellow/orange on #1 and #4 cylinders. Am also using the standard tuning procedures per video.
Will try bending float level 1/8 down.
All adjustments were made with eng. @ normal operating temps.
Thanks to all for your input. Will post my results when I figure this out.
Regards,
Ken
 
Try re-centered your jets and be sure the piston drops easily and with an audible click. As someone said before, be sure the jets are really raised all the way. Finally, do you have oil in the carbs?
 
Ken,

One of the common mistakes people make when rebuilding carbs is to fail to remove the old jet seal cork at the top of the jet bearing assembly. It is small and gets jammed up there and is hard to see. It is worth checking to see if you failed to remove the old one before you inserted the new one. This may be the source of your problem.(??)
 
Thanks for the info, am going to pull the carbs off and take a close look for that seal and everything else.
Ken
1960 Bugeye
 
Wanted to note that others have said that with modern gas the "color tune" will read a little rich when the mixture is right. How does it drive? What kind of gas mileage are you getting? What do the plugs look like after a drive?

Kurt.
 
Hi, Ken,

If the problem is with the old jet seal cork, please let me know.
 
did you replace the shafts?
if you did are we sure the butterflies are in situ correctly .
they have an angle cut to them so completely close even at the slight angle at closed throttle .
 
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