I have two Zenith Stromberg carburetors on my 1969 XKE series Two 2+2 coup. I overhauled them several years ago. Last year, I replaced two bypass valve diaphragms and this year I replaced the both fuel filters. The fuel pump seems to pump strong, thought I have never tested the flow/pressure rate.

I note that the car has excellent acceleration until 70 MPH. Often, between 70 and 85 MPH the engine starts to splutter as if it is fuel starved. I accelerate the engine speed will not increase even if I apply the choke. I have to drop back to 55/60 MPH before the engine normalizes.

Any ideas on what is going on and suggested solutions would be appreciated.

Submitted by Anonymous (not verified) on Sat, 01/14/2017 - 02:40

Could be a number of things.
1. Make sure battery terminals are tight. (vibrations at that speed could cause this)
2. Ensure there terminal in the distributor cap are clean and no wear or cracks. Leads should have clean ends.
3. Likely cause is weights in the distributor might be sticking. Get distributor cleaned.