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hi i got a 450 holley economaster carb on my 253 and when you kick it hard it back fires through the carb. it all so has a flat spot in the start of it,been like this from the start form new. do you think i'm better off putting a 465 holley on. tryed changing mixter but makes no differents. any done 5000 k's with this carb. my engine had a full rebuild at the same time.
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hi Barry..i think you should do one thing at a time..here they are in no order...check timing(twice!)with a light..change plugs..change points(if you have them)screw in the mixture and stop when it struggles and back out half a turn....if that doesnt work |
Jim in Adelaide.. |
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pss...check the bottom of the engine is timing up with the top..ive seen this too! |
Jim in Adelaide.. |
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one other thing,not trying to be rude,if you want our help ,we are happy to help,but you ll get more help if your not ANONYMIS in my opinion!woops |
Jim in Adelaide.. |
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If the car is running OK apart from when you nail it, Id check the accelerator pump. Make sure its working, and see that the shooters arent blocked at all. Also check for air leaks. If its running too lean when you nail it can cause a backfire. And if the
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If the car is running OK apart from when you nail it, I'd check the accelerator pump. Make sure it's working, and see that the shooters aren't blocked at all. Also check for air leaks. If it's running too lean when you nail it can cause a backfire. And if
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thanks , will do all the checks and look at the accelerator pump.
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As a warning, if your harmonic balancer isn't sparkly new, timing it on the light could put you wrong. I have had the balancer rings shift by as much as 10 degrees. While it is running, undo lock nut and gently rotate dizzy and listen for results. I us |
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As a warning, if your harmonic balancer isnt sparkly new, timing it on the light could put you wrong. I have had the balancer rings shift by as much as 10 degrees. While it is running, undo lock nut and gently rotate dizzy and listen for results. I usu |
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Keep the shiny side up, and the greasy side down. |
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inspect power valve.
once a holley backfires, these sometimes fail.
common fault.
He who hesitates, -Masturbates. |
Old holdens brought on the spot, quick decision, cash paid. |
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This has happened to me once and it turned out the be the Cam.
One of the inlet lobes were severly worn causing the lifiter to stay open too long causing compression to come through the Carby. Check that you Lifters are functioning correctly.
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ok i fitted a new holley kit , checked the timming and the pionts and stills back fires on hard kick. check timing again and found that the balancer sometimes changes from 6 degs to about 9-10 degs . i know its not the timing chian as i fitted new timing
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ok i fitted a new holley kit , checked the timming and the pionts and stills back fires on hard kick. check timing again and found that the balancer sometimes changes from 6 degs to about 9-10 degs . i know it's not the timing chian as i fitted new timing
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tighten /check your rocker gear. 1st
He who hesitates, -Masturbates. |
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rubber sandwich inbetween the outer and inner ring is slipping, so you get a false timing read. the inner of the balancer is on the crank with keyway, then rubber, then outer. the inner spins more that tne outer cos the rubber is knackered, therefore wron
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Also, make sure you check the timing with the vacuum line removed. If it is backfiring with hard kick, your vaccuum line may also be connected to the manifold vacuum rather than venturi vacuum port. Effectively the vacuum advance will be working the wro |
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