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2500 SU carbs problem


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Hi all

Car has been very running well, but discovered leak on front carb jet, so have replaced.

Leak cured but now running very rough at low speed and tickover. 

I thought it would be a straight swap, as I have not changed any adjustments.

Anyone any ideas?

It is definitely the correct jet!

many thanks



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Can only suggest  the  new jet is not fully returning to sit up against its adjusting nut  

often a SU headache   can be the tube needs a 3 -4 mm cutting off as they seem too long and this 

hangs the jet up , have a quiet prod on the jet see if it pops back up fully 

there are few other reasons based on its just a jet swap 

you probable know i have a hate of anything SU and ive got two HS4s on my 2000 as well  

hey ho !  but apart from ridged floats they seem to be fine  (say that quietly you know they listen )


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Checked the choke and operation of jets, all normal.

So I fitted a replacement plastic pipe in original jet I used locktite to seal the pipe in the jet.

No leaks and now running normally, so Venturi of new jet must be different/wrong.

Thanks for your suggestions!

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