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a "b" with no top end.

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  • a "b" with no top end.

    hi. marina base, "b" series 1.8, single hs6 carb.with bas needle. can not get rpm above 4000.
    starts and runs well to approx. 60 mph then goes "flat". have tried various settings with the jet adjuster nut, and also timing. plus air filter on/off.some piston damper oil is forced out of vent hole in the black plastic top. silencer is a marlin s/s. thanks for any advice.

  • #2
    Re: a "b" with no top end.

    Hi Bob
    My Marlin has the same engine etc and I think the same carb. What air filter have you squeezed in - my car has an old pancake type with no filter medium!! Just wondered what you use? I live at Wickham (on the B4000) so I will keep an eye out for your car this summer.
    Sorry I can't help you with your carb problem but hope someone else can.
    Good luck

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    • #3
      Re: a "b" with no top end.

      Hi Bob, Just a thought, is the carb icing up!!!
      Terry

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      • #4
        Re: a "b" with no top end.

        Bob, Has this issue just happened suddenly or it just got worse over time ?.
        With the car out of gear will the engine rev above 4000erpm up to 6000 rpm ?.
        If not has the throtle cable slipped back or a restriction in the full throtle movement.
        check the chock for sticking on or being operated.
        check fuel lines and pump suppling plenty of fuel. Is the fuel tank vent breathing,when you operate the full throtle is the needle piston lifting max distance. have you checked the engines valve clearance (to tight). exhaust restrictions.
        Is this your 1st start this year with last years fuel in the tank.
        check the air supply from the inlet manifold to the brake servo for leaks as it could be the seal in the servo.
        Check inlet manifold to cyl head for being tight and gasket ok.
        Good luck.....Bob

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        • #5
          Re: a "b" with no top end.

          Is ignition advancing - check with strobe
          Points gap set ok- this may sound silly but dont mix metric sttings with imperial
          Ignition tracking?

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          • #6
            Re: a "b" with no top end.

            Bob
            Did you get your B series engine reves issue sorted ?.

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            • #7
              Re: a "b" with no top end.

              hi.bob still no high revs. it has been like this since i first had it. full throtle movement okay. choke okay,but have had to wind adjusting nut right up to the top to get even tick over. air filter on/off. any ideas why some damper oil is forced out of small breather hole in black plastic top?.new fuel pump.lines and breathing okay.air pipe to servo on tight and looks okay.the s/s silencer when you tap it sounds a bit tinny.i will see if she goes above 4000 out of gear.,but it is too cold for me in the garage at present!!. thanks for your help.

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              • #8
                Re: a "b" with no top end.

                Has it always been like this Bob?
                Have you checked the cam timing?
                If you lift the piston up with your finger does it go right to the top smoothly and drop down again with a clunk?
                Also sounds like you have too much oil in the damper, it should just come to the top of the piston tube.
                What oil are you using in it, the damper that is?
                If you have to wind the jet holder right up to get it to tick over it sounds as if it's running rich. Can you see any wear marks on the needle or jet? Does the jet hole look round or has it been worn on one side?
                Have you checked the float chamber level as this can cause it too run rich if too high?
                Hope some of this might help, best of luck, Hugh.

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                • #9
                  Re: a "b" with no top end.

                  Bob
                  I would go with Hugh's comments on the needle /jet combination - the adjusting nut should be around 2 -3 turns out [thats a pretty much standard setting for Su carbs] If you are stripping the carb down then its a good idea to check the spindle for wear, any appreciable wear will mean that you won't be able to get an even idle. Repacement spindles used to be available and may still be so from someone like Burlen Services who certainly do needles and jets.Check also the float valve is shutting off or as Hugh say's you will get too high a fuel level in the float chamber causing it to be rich.

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