Section : Carburettors

flooding rear su carb

Posted By : Noel Watkins, 30-Nov-2005, 10:54pm

• flooding rear su carb

  Posted By : Clive Speaks, 01-Dec-2005, 08:36am

  Noel,
  Fit an in line filter as close to the feed side of the carbs as you can and as soon as you can. They only cost about 90p and may well solve your problems. we had a similar run with the 2000 saloon. Off the road for 10 years and before that 26 years in Africa. God knows what was in the tank, but once we got her going, it all arrived in the carbs.
  90 pence worth of filter fixed it in a jiffy.
  BTW, you almost never see the offending speck of dirt, as soon as you remove the float, the petrol flow washes it away.

  • flooding rear su carb

    Posted By : Philip Brammer, 01-Dec-2005, 09:25am

    I agree with Colin. The only reason a carb will flood is because the needle valve is not seating properly. You've ruled out the valve so it must be crud in the fuel. There is a filter on the top of the fuel pump but it's pretty useless, you need to fit an in line one. Any one from anywhere will do the job. Don't forget to blow out the fuel line from the filter to the carbs once you have fitted it to clear any residual bits. PS It will be the rear carb all the time cos' thats the first needle valve the crud will stick in.
    Have fun Noel...you do know that the hammer banging frustration is all part of the attraction to Triumphs?

    • flooding rear su carb

      Posted By : Noel Watkins, 01-Dec-2005, 04:46pm

      Thanks chaps,could it really be that simple,having owned three Alfas in the past,i tend to assume the worst and am well aware of hammer banging frustration.Should I remove the washer as this seems to have made no difference and the float now stops rising at a much lower level than the front carb,will keep you posted, and once again thanks.

      • flooding rear su carb

        Posted By : Barry Huffer, 02-Dec-2005, 02:08pm

        When I had this problem on a Spitfire the fuel was coming out of the carb not the overflow but one suggested cause was that the fuel pump pressure was too high and keeping the float valve open.
        
        It may be a long shot and the fact that is only happening on one not the other suggests its not the cause unless one float is weaker than the other.
        
        I finally got the answer to my problem from Burlen Tech Support my overflow pipe was blocked and didn't allow atmospheric pressure in the float chamber keeping the valve open and it overflowed through the carb.
        
        If you haven't tried Burlen it could be worth it nice people to deal with.
        
        
        Regards

      • flooding rear su carb

        Posted By : Clive Speaks, 05-Dec-2005, 11:34am

        One other thought, if the fuel pump diaphragm has gone hard, then the little return valves that go through it might well be semi-seized. If this happens, then as there is no tank return on a Spit, the pressure could build up as high as 4-5 psi. In other words enough to overcome the float's reststance and overflow the rear carbs float chamber. Once again not dear to fix but another place to look if the filter doesn't cure things.

        • flooding rear su carb

          Posted By : Noel Watkins, 06-Dec-2005, 11:06pm

          Hello to everyone who offered their advice.Inline filter fitted early yesterday,once again everything seemed fine until about 2 minutes after the mechanic left,no charge by the way. I started it and to my chagrin,same problem,took the lid off the float chamber,removed the needle seat and obviously needle.Specks of dirt,so decided to clean lid and chamber,using a mixture of cotton buds,kitchen towell,a syringe and clean petrol,float chamber still in situ.There was a lot of crud in the bottom of the chamber,i removed the washer from the needle seat,put it all back together and,well driven it four times today and no overflowing,hoorah.Except,she now gets hot a little to quickly for my liking,fan on after about 5 mins,temp gauge reading three quarters after same amount of time,and she runs on after switching off,only for a few seconds,still at least i don't have petrol pouring all over the ground.Oh the joys of owning a triumph,and i've only had it six months,no time at all,i'm sure compared to some of you chaps,you have my respect and thanks.