AMGBA website home page or AMGBA Photo Gallery or AMGBA Club Blog
Subscribe in a reader


Join or renew today and receive a free t-shirt or tech CD, see details in the join the club section at www.mgclub.org!

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

0 Members and 1 Guest are viewing this topic.

september2021

  • An AMGBA Club Member
  • ***
  • Posts: 19
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

amgba

  • American MGB Association
  • AMGBA Club Administrator
  • *****
  • Posts: 702
  • American MGB Association
    • American MGB Association
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
website: www.mgclub.org
email: info@mgclub.org
phone/text: 773-769-7084

North America's oldest and largest club for all MGBs, MGB-GTs & Midgets.  A nonprofit organization founded in 1975 and offers color magazines, emagazines, technical advice, member recommendations on service shops, registration of your MG, a tradition of service & FREE member classified ads that appear in the magazine & on the website.


 

   AMGBA website home page or AMGBA Photo Gallery or AMGBA Club Blog