Rough Idle with Warm-hot Engine / stop -start

Discussion in 'Mech Tech' started by Andyvan1, Jul 10, 2019.

  1. HELP .....!
    Can any body give me some advice with this annoying issue :

    Issue: Very poor idle when engine is hot/warm BUT Only when engine is turned off and back on again.

    Engine idles well and drives fine when cold or hot in both stationary traffic and at speed 50-60 MPH ! – usual run of ¾-1hrs drive to work in rush hour I will have no issues.

    BUT annoying.......:(

    Turn off the engine when hot and re-start after 5-10mins the engine will re-start but idle badly and then install. Sometimes it will be impossible to re-start the engine. The engine will turn over ok but not fire up. If you keep your foot on the gas it will run… but then install at idle.

    The Issue only seems to happen after the engine is switched off (when hot) and back on again within a 5-10 mins. (Typically a quick stop at the shops after a run does the job !)

    Other bits

    1600 AD engine
    34 PIC Single Carb (with Auto Choke ) - with aftermarket K&N filter.
    009 Dizzy

    So far i have done the easy bit .... New points, new condenser, new cap, new rotor arm.

    Any suggestion before it goes to the garage. :worship:
  2. How are you starting it and does it improve if you give it a good blip after starting.
  3. Probably not related to the poor running but you'd do well to switch over to a SVDA dizzy. Have you checked all the basics: timing, valves adjusted?
  4. Yes, checked and adjusted the timing after putting in new points.
    The valve clearances were adjusted 1000 miles ago.
  5. Slowly pressing down on the gas pedal and turn the key !
  6. Dubs

    Dubs Sponsor

    Have you checked the choke isn't coming back on while your in the shop? It may just need adjusting back a bit.

    Also check the cut of solenoid is still functioning properly when hot...
    mikedjames, Lasty and Andyvan1 like this.
  7. ^this, before you start dismantling the ignition. If the choke comes back on (they are very enthusiastic), you'll be running horribly rich and the engine will splutter.
    mikedjames and Andyvan1 like this.
  8. How do you adjust the automatic choke ?
  9. Dubs

    Dubs Sponsor

    Take the airfilter off, and there you will see 3 m5 screws on the choke body ring. Slacken them a bit, turn the choke in the desired direction, tighten the screws again.

    Before you do that though, do your usual drive, then park on your drive with the engine off, for however long it normally takes to go wrong, then take the airfilter off and check to see if it is closing in that time. You will need to open the throttle once so the choke can move if it wants to.
    Andyvan1 likes this.
  10. How do you
  11. Cheers for the excellent clear instructions...hoping it works out...will try on the weekend
    for forb
    Dubs and snotty like this.
  12. Many thanks for the advice, I checked the cut off solenoid and it was loose and sticky ... it wouldn’t actuate when 12v lead was taken off and then put back on .
    Renewed it and did the test drive and stop and start up ..., with no issues
    Cheers for the advice
    Dubs likes this.
  13. Dubs

    Dubs Sponsor

    Happy days! :thumbsup:

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