qim Posted November 7, 2017 Report Share Posted November 7, 2017 I had a small leak from the connection of the ptrol pump to the pipe leading to the carbs, and as I had a spare pipe had it installed today. I got it sometime ago from either Rimmer or Revington and the thickness was larger than what I had. When I started the car there was a lot of petrol leaking from the forward float chamber. The problem was solved by inserting a washer in the mechanism to reduce the travel of the float. I wonder if this was a disaster about to happen that was brough tforward by the increased flow of petrol; or if it should not have happened and was caused by an incorrect, large pipe. Also, was the introduction of the washers a reasonable repair, or should I urgently have the float chambers properly repaired- Camilo Quote Link to post Share on other sites
Paul J Posted November 7, 2017 Report Share Posted November 7, 2017 I had a similar problem last week after replacing a fuel pipe, my rear float chamber flooded, the cause was a small shred of hose obstructing the float valve. Paul Quote Link to post Share on other sites
RogerH Posted November 7, 2017 Report Share Posted November 7, 2017 Hi Camilo, the pipe itself should not be the problem as the total flow is restricted by the brass pipe on top of the float chamber. As Paul mentions - have a look for debris in/around the float valve. Whilst looking make sure the float valve gap is correct. Roger Quote Link to post Share on other sites
Fireman049 Posted November 7, 2017 Report Share Posted November 7, 2017 +1 Roger ~ Make sure the floats are set-up as per the SU manual. Tom. Quote Link to post Share on other sites
qim Posted November 7, 2017 Author Report Share Posted November 7, 2017 (edited) Hi Camilo, the pipe itself should not be the problem as the total flow is restricted by the brass pipe on top of the float chamber. As Paul mentions - have a look for debris in/around the float valve. Whilst looking make sure the float valve gap is correct. Roger Hi Roger What is the gap? And what do you say about this added washer to solve the problem? Edited November 7, 2017 by qim Quote Link to post Share on other sites
Fireman049 Posted November 7, 2017 Report Share Posted November 7, 2017 Hi Camilo ~ As you have HS6 SU's I think that the gap is 0.125" (One eighth of an inch). I stand to be corrected as I run H6 carbs! Tom. Quote Link to post Share on other sites
RogerH Posted November 7, 2017 Report Share Posted November 7, 2017 Hi Camilo, have a look here http://sucarb.co.uk/technical-carburetter-maintenace-setting-float-height The washer is a bad idea. Roger Quote Link to post Share on other sites
Revolution Posted November 7, 2017 Report Share Posted November 7, 2017 Hi Camilo For what it's worth, I had all sorts of problems with my HS6's on my TR4a about 2 years ago and i just couldn't stop them flooding I tried everything, well almost I guess, and in desperation fitted a Fuel Pressure Regulator and since then I have had not one problem with flooding and the car runs beautifully Now it may be that I didn't get to the root cause (poss the fuel pump pushing too much fuel through rather than the carbs) but it has been a fairly inexpensive fix So I would try a substitute fuel pump and if that doesn't solve the problem go for the Regulator Hope this helps, Nick Quote Link to post Share on other sites
boxofbits Posted November 7, 2017 Report Share Posted November 7, 2017 I stopped my HS6's flooding by inserting a small in-line relatively inexpensive paper element fuel filter bulb between the pump and float chambers. I think it was around £2 from a car show, or is available from motor factors. Never had a problem since. Kevin Quote Link to post Share on other sites
qim Posted November 7, 2017 Author Report Share Posted November 7, 2017 (edited) Hi Camilo For what it's worth, I had all sorts of problems with my HS6's on my TR4a about 2 years ago and i just couldn't stop them flooding I tried everything, well almost I guess, and in desperation fitted a Fuel Pressure Regulator and since then I have had not one problem with flooding and the car runs beautifully Now it may be that I didn't get to the root cause (poss the fuel pump pushing too much fuel through rather than the carbs) but it has been a fairly inexpensive fix So I would try a substitute fuel pump and if that doesn't solve the problem go for the Regulator Hope this helps, Nick Hi Nick and Kevin To be fair to the carbs and floats, I have the car since 1977 and never had an issue with them. I assume that the problem today was caused by the larger pipe, but it may have been a blessing in disguise as it may have been about to happen anyway. From what I saw the mechanic do (black magic, to me!) the float was moving all the way to the top, allowing the bowl to fill up totally. I think that his solution with the washer was to stop the float from rising so high. I looked in the Moss catalogue to see if there was a repair kit, but they just have all the various different parts. Could it be that the rise of the float can be regulated with a feeler gauge rather than inserting a washer? or is there something that wears out over the years (and I assume my floats are 58 years old!). Edited November 7, 2017 by qim Quote Link to post Share on other sites
RobH Posted November 7, 2017 Report Share Posted November 7, 2017 (edited) Camilo - floats can cease to float if they have a leak but they don't wear out. The most likely cause is the last thing you changed as Paul suggests - crud in the needle valve from changing the pipe. If your floats have the thin metal arm at the top which operates the valve, you adjust the gap by bending that arm, not by putting washers under the valve. Turn the lid upside down so that the float presses on the valve under its own weight and the gap between the top of the float and the lid of the float chamber should be 1/8 inch to 3/16 inch (3.2 to 4.8mm). You can't adjust that if it has the solid nylon floats though. You shouldn't need a pressure regulator nor an extra filter with the standard pump as it is matched to the carbs for pressure. Edited November 7, 2017 by RobH Quote Link to post Share on other sites
qim Posted November 7, 2017 Author Report Share Posted November 7, 2017 (edited) Hi Rob I've been reading to try and understand these float chambers and I think I got it. Going back to the washers that the mech inserted away from me, I guess that what he did is what is described here (at 2:00 mins of the video) in floats that do not have the metal part that you can bend. I will go and see him tomorrow to make sure that is what he did, Edited November 7, 2017 by qim Quote Link to post Share on other sites
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