runs rough once dropped in gear

Good morning,
My 308 in the '52 Twin H Hornet fires right up and runs smoothly. However, once I drop it into gear, the car shakes and the motor nearly dies. Once up to speed, all is fine. Any ideas why this turbulence is taking place?

Thank you.

Comments

  • railknight
    railknight Expert Adviser
    Does your engine run rough or misfire when accelerating too?  Has this been an issue for a while or did it just begin after the engine ran fine previously?
  • As far as I can tell, no misfiring. I did have. the tranny and engine out for a repair. Wondering if this is a kick-down linkage issue or vacuum related. 
  • Is it the same behavior in all gears? D,L,R?
  • BigSky
    BigSky Senior Contributor
    Doesn’t have electric hand does it?
  • eddiehudson
    eddiehudson Senior Contributor, Member
    devin said:
    Good morning,
    My 308 in the '52 Twin H Hornet fires right up and runs smoothly. However, once I drop it into gear, the car shakes and the motor nearly dies. Once up to speed, all is fine. Any ideas why this turbulence is taking place?

    Thank you.

    Check the idle speed, and make sure the choke is not sticking.
  • Thank you to mall for your thoughts. I will check matters on the weekend and report back. 
  • Sounds like the carbs need to be synched in, maybe it’s to lean, also check timing, vacuum advance for operation and leaks. Also check engine for vacuum leaks around manifolds, wiper motor and hoses for that. 
  • 7XPacemaker
    7XPacemaker Senior Contributor
    Or have someone start it up and put it in gear. Go under the hood and spray suspected areas with starting fluid. If it smooths out, isolated the area to the source.
  • Uncle Josh
    Uncle Josh Senior Contributor
    I hate to be the bearer of bad news, but If worse comes to worse, I worked on a 308 w/automatic that did that.  Compression test didn't look good on #1 and 2.  Pulled the (aluminum) head and gasket was blown between the cylinders and had eaten a track in the head.  New gasket and iron head.  The aluminum ones are wall hangers when they get old.
  • ...loose engine ground strap?
  • Thank you to all for your professional opinions. Problem resolved: carbs were out of whack and needed cleaning. Also put in a Pertronix Ign. Running like a watch now.
  • Zzapped
    Zzapped Member
    devin said:
    Thank you to all for your professional opinions. Problem resolved: carbs were out of whack and needed cleaning. Also put in a Pertronix Ign. Running like a watch now.
    Are you running 6 volt, if so what product number on the Pentronix.
    Thanks