Hunting tach and back fire

[Jmulloy]

I have a 1973 TVR 2500M. Last winter I installed a rebuilt Halkias engine and brand new SU carbs. Car had been running very well during break in period and then I had my car guy here lean out the carbs. Now I'm getting some intermittent back fire at highway speeds and when the car slows down my RPMs drop to the point where the car nearly stalls and then catches it's breath before spooning back up. RPMs seem to be hunting.

Any thoughts and ideas?

John

 

[LarryK]

If all was good before the requested lean out, might want to go back to original settings.

 

[Grantura_MKI]

It maybe a connection with the ignition? What are you using?

 

[Jmulloy]

I have a Lucas distributor with points.

 

[Grantura_MKI]

Is the coil cool to the touch, or very warm?

 

[Jmulloy]

I'll check this weekend. It is a brand new flame thrower.

 

[Grantura_MKI]

That's a great coil.

 

[TomMull]

If all was good before the requested lean out, might want to go back to original settings.

Agree, both conditions could result from an overly lean mixture. Tom

 

[Grantura_MKI]

Also need to know if the temps are up? Would check the plugs, etc. not easy from here.