Jump to content

SU carbs running too rich


Recommended Posts

Andy you may be right but as the shoulder is proud of the Brass bit I'm assuming it's flush with the aluminium face of the dashpot itself.

 

If not put a straight edge across the face and pull the needle down to it, the job's done.

 

Apart from a tendency to flood (for me and my son only?) SUs are dead easy IMO.

 

Ash

Link to post
Share on other sites

Hello to all.

 

As I wrote earlier, I lowered the needles by about 0.5 mm below the piston face and tested again the engine. With the jet nut at its uppermost position, there was a clear lean mixture operation symptom.

 

I was able to achieve around 5% CO in the exhaust by turning only 3 flats (half turn) in the jet nut, what seems to be too little (recommendations are around 6 or 9 flats), and surely the problem of too large a jet orifice still persists.

 

The engine seems to run fine, but I have still to test the spark plug conditions after a serious drive.

 

In all, I hope that changing to new jets, the situation will improve, and I will try to go back to the correct needle position.

 

I'll post the news.

 

Thanks again for your help.

 

Jesús

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.