No power under pressure

Discussion in 'Mech Tech' started by Flying Pig, May 30, 2020.

  1. Dubs

    Dubs Sponsor supporter extraordinaire

    Vac advance working OK? Pump jets squirting nicely?
     
  2. Checked coil? Electronic ignition, or points? Who did the carb rebuild, what carbs again?
     
    1973daisey likes this.
  3. I'll check again , are they that temperamental ?.
    One more idea to consider and check up
     
  4. Jets squirting nicely , new dizzy and coil so will check again
     
  5. Electronic ignition new , but same symptoms with original with points set up
     
  6. Floats set correctly?
     
  7. Ours was a bit gutless on hills when the plug lead rattled off enough to reduce effect.

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    Flying Pig likes this.
  8. Just checked for air leaks again with wd 40. On the servo tee there is no change in engine sound with the wd but when I press the pedal at idle there is a slight change to engine note ?. Should there be any note change at all ? . Thanks again for all the replies .
     
  9. Dubs

    Dubs Sponsor supporter extraordinaire

    Idle should rise slightly as the brake pedal is pushed, so sounds like yours is OK.
     
    Flying Pig likes this.
  10. Faust

    Faust Supporter

    Just a simple check possibility ....is your accelerator cable slipping out of the clamp at rear or at the front .
    So when you full power it it's slipping out ...i have had this .
     
    Flying Pig likes this.
  11. When it gets cooler later on I'm going to go over all the suggestions one by one to rule out once and for all . It's a shame because it starts ticks over , pulls away but does under pressure. I'll post back my finds ,cheers all
     
  12. Properly empty ??

    Crud may have settled ...

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    Flying Pig likes this.
  13. Zed

    Zed Gradually getting grumpier

    Lack of fuel, weak spark, sticky advance. So many possibilities under that large umbrella. Good luck.
     
    Flying Pig likes this.
  14. I'll check the tank outlet again later
     
    Lasty likes this.
  15. Does seem so . What effect will having the air box off have on the engine running if I leave it off to test drive each time ?. Also if I do leave off where should I put the pipe from the balance pipe? . Can it be blocked off temporarily?
     
  16. Zed

    Zed Gradually getting grumpier

    I think you mean the tiny one from the idle circuit under the filter?..

    You shouldn't risk it, some crud might get sucked into a carb and the idle circuit needs that short metal pipe on the left arm to operate properly.
     
    Flying Pig likes this.
  17. Zed

    Zed Gradually getting grumpier

    Talking of air filters, not choked with oil from the breather is it?
     
  18. This has probably been mentioned, but have you checked the needle jet , it could have crap behind it or it’s failing to close off causing the opposite by flooding under load. This happened to me in Dorset


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  19. Hi , theres no oil from the breather pipe. I'll put all back the when checked and then try .
    Hi thanks, I'll check that tomorrow as I'm going to remove the carbs and check over again .
    Gonna sort out a fan In the shed and go over the whole lot , again lol.
     
    paul2590 likes this.
  20. I'll throw you another one in. This happened to me in Belgium after I'd fitted new float valves. I limped it back home then found the ball bearing in one of the valves had dropped out.
     
    Flying Pig and Zed like this.

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