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Author Topic: Car Stuttering at High RPM  (Read 128 times)

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Car Stuttering at High RPM
« on: August 06, 2021, 01:19:52 PM »
Our '77 MGB with a coil, 25D distributor, and professionally rebuilt Zenith Stromberg carb can rev up to 5K just fine in neutral.  But, when it is in 2nd or 3rd it will start to stutter at around 3500 and 4000 rpm.   

I am thinking this is a vacuum advance issue.  Should I check other things like timing?

Patrick Lewis


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Re: Car Stuttering at High RPM
« Reply #1 on: August 06, 2021, 01:31:59 PM »
Check your fuel delivery. It takes more fuel to drive a car to 5000 rpms as opposed to it revving to 5000 sitting in your driveway.

You could also have spark issues as spark can change under a load.

Could be timing.

Unlikely vacuum leak as that would be noticeable at idle and other rpms.

Did you make any changes right before this started?

Time to start checking basics.

Patrick Dockerty
American MGB Association
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