Baxendale Posted July 6, 2009 Share Posted July 6, 2009 Hi, I have updated my SU petrol pump with an electronic kit to replace the contacts. I now find that the pressure fromm the pump is so good it overcomes the needle valves in the float chambers. Does anyone have any ideas on how I can reduce the pressure output from the pump? Quote Link to comment Share on other sites More sharing options...
ted angus Posted July 6, 2009 Share Posted July 6, 2009 I just repleced the SU on my Gipsy with a solid state Toacan I bought via an e bay shop to date I am really pleased starts first touch of the key now wether hot or cold. Are you sure you have bought the correct spec pump ?? Also some pumps are designed to be on top of the tank others are designed to be much nearer the carb regards TED Quote Link to comment Share on other sites More sharing options...
Baxendale Posted July 7, 2009 Author Share Posted July 7, 2009 Hi Ted. I am aware that there are pull and push variants. The SU pump is the original SU pump and placed near the carb on the front bulkhead, i.e. it pulls the fuel from the tank at the rear. It maybe, that the change to electronic points means that it is too good for the job! Quote Link to comment Share on other sites More sharing options...
sirhc Posted July 7, 2009 Share Posted July 7, 2009 It sounds like you've got a pump which is too powerful for the application. Maybe you need to fit a flow restrictor of some kind? Quote Link to comment Share on other sites More sharing options...
Adrian Barrell Posted July 7, 2009 Share Posted July 7, 2009 You could also try a T piece between the pump and the carb with a return to the tank. Quote Link to comment Share on other sites More sharing options...
Tony B Posted July 7, 2009 Share Posted July 7, 2009 Where did you get the conversion kit? The 101 Ambulance has two of the SU pumps. One for engine, one for Esprbacher. Quote Link to comment Share on other sites More sharing options...
Baxendale Posted July 7, 2009 Author Share Posted July 7, 2009 Hi. If I add in a T back to the tank as a bypass then there will be no back pressure to stop the pump working continuoiusly, nice lateral thinking though. re where did I get the kits from, I will ask my brother and post a reply later on that. Quote Link to comment Share on other sites More sharing options...
Adrian Barrell Posted July 7, 2009 Share Posted July 7, 2009 Hi. If I add in a T back to the tank as a bypass then there will be no back pressure to stop the pump working continuoiusly, nice lateral thinking though. QUOTE] If the pipe is small and/or long enough, there will be! It is a trick sometimes used when fuel evaporation is a problem. It allows a continuous flow of fuel through most of the system which carries heat away from the componants. Trust me, it works! Quote Link to comment Share on other sites More sharing options...
Mark Posted July 7, 2009 Share Posted July 7, 2009 Hi. If I add in a T back to the tank as a bypass then there will be no back pressure to stop the pump working continuoiusly, nice lateral thinking though. QUOTE] If the pipe is small and/or long enough, there will be! It is a trick sometimes used when fuel evaporation is a problem. It allows a continuous flow of fuel through most of the system which carries heat away from the componants. Trust me, it works! Adrian, could you explain that in a bit more depth please (hard of hearing) Quote Link to comment Share on other sites More sharing options...
Guest catweazle (Banned Member) Posted July 7, 2009 Share Posted July 7, 2009 Hi. If I add in a T back to the tank as a bypass then there will be no back pressure to stop the pump working continuoiusly, nice lateral thinking though. QUOTE] If the pipe is small and/or long enough, there will be! It is a trick sometimes used when fuel evaporation is a problem. It allows a continuous flow of fuel through most of the system which carries heat away from the componants. Trust me, it works! I have been harping on about this for months all this old stuff we drive around in benefits from this listen to the man.:-D Quote Link to comment Share on other sites More sharing options...
Mark Posted July 7, 2009 Share Posted July 7, 2009 I have been harping on about this for months all this old stuff we drive around in benefits from this listen to the man.:-D So if I done this on my landrover, then the problem of starting it when hot would/should go away. ? Quote Link to comment Share on other sites More sharing options...
Guest catweazle (Banned Member) Posted July 7, 2009 Share Posted July 7, 2009 So if I done this on my landrover, then the problem of starting it when hot would/should go away. ? If its due to fuel vaporising then yes. Quote Link to comment Share on other sites More sharing options...
goanna Posted July 8, 2009 Share Posted July 8, 2009 I've been through this with my series 1 Land Rover .The pressure the needle and seat in the carby looks at ..has nothing to do with the points in the pump ..all the points do is switch the current on and off . The pressure is FULLY dependant on the diaphram spring tension..the spring that sits behind the diaphram ..More diaphram spring pressure = higher psi at the needle/seat. It's basic physics . The SU pump was made in LP and HP versions . Mike Quote Link to comment Share on other sites More sharing options...
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