Moss Motors, Ltd

I've just had fitted a 1950cc Stage 2 engine and my Weber 45 was refitted and jetted accordingly.  The problem I now have is when travelling at a constant speed says 50mph it seems quite happy for a minute and then seems to hold back as if too little or too much fuel is getting to the carb.  It doesn't dramatically do it but it makes crusing annoying.  If I accelerate its fine and if I slow its fine.

 Also tick over seems quite high (around 1200rpm) but after a long run the idle speed will increase to 2000rpm.  I am going to look at the idle speed anyway when I get a chance but does anybody have any ideas how to solve the above and what maybe increasing the idle?

 The specialist that fitted the engine and set it up doesn't seem bothered about this as if its something I have to sort out as its "nothing caused by what he's done".  Only pciked the car up Saturday and have done about 200 miles.

 

any suggestions will be much appreciated.

Vitmo,

First impression, vaccuum leak that gets worse w/heat. Is the carburetter flexibly mounted? These flexible mounts can be a pain...

Second impression, Carburetter possibly not ideally set up, perhaps w/ too big a choke (throat insert)

Third impression, poor fuel delivery. Easily checked.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon