Before I rebuilt my 3 SU's the front carb was sucking more than the others. Even with the slow run volume screw - screwed all the way down the uni-syn showed more air volume than the other 2 carbs. Cant get the car to idle down less than 1200 rpm. I rebuilt the carburetters, throttle shafts are good, piston, slides, and suction chambers appear to be good. All butterfly values are fully closed during tuning. I am still having the problem the front carb sucking more than the others, even with the slow run volume screw closed and the distributor vacuum line closed off. Any advise would appreciate???
Thanks,
George Jones (owner since 1979)

 

Welcome to the forum George,

I've moved your question from Jaguar Forums Advice / Feedback & Suggestion Center to E-Type (XKE) forum. The Advice / Feedback & Suggestion Center is for posts about the forum and not for technical questions.

Members here with the same model will be able to help.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Speaking only from my personal experience, and I don't want to discuss the abilities of the machinist, I had the head on my '64 3.8 rebuilt and had the same problem. After hours of trying to resolve it I finally took it to a local Jaguar guru. He had the same problem and finally ran a compression check.


Come to find out I had a bent valve! He fixed that problem, put everything back together and the car idled down to just over 600 rpm just as smooth as ever!!


For what it's worth.


Charlie

 

Am in the process of rebuilding 189 SU ! and I have had the same problem as you.....
after checking that I had NO air getting by the butterfly valves I knew that air was getting by into one carb Sooooo I took masking tape and wrapped lots of it around the gasket/spacer area of the offending carb this proved that I had an air leak at the manifold/carb junction ( part of the heat insulator had broken away underneath and could not be seen) the masking tape sealed up the leak and now I had solved the problem with new gaskets and an insulator.

 

If you stuff a thick grease around the throttle shafts and the engine idles ok you know you have fixed the leak there ! Some times the old plastic throttle shaft bearings can wear and partially break away then getting sucked into the engine (no harm done, they just burn up) replace the bearings with new metal ones and seals and you should be OK.