Mark,
Making the assumption that your carburettor is not full of crud that can occasionally partially block a jet, the half-full filter symptom is certainly a possibility with regards to what could be responsible for your problem. Filters need to be full of fuel at all times and to achieve this without auto-bleeds this means that they should be vertical with the fuel flowing upwards. The cheap filter type is fine as those which I have encountered seem to be a standard type that is available through most motor factors and Halfords. They certainly appear to have a high enough flow capacity to cope with both engine supply and recirculation fuel with an injection system. If your filter is on the suction side of the pump then it is more difficult to initially get the filter to self-bleed but time and vibration help a lot if the filter is vertical. It is better with regard to self-bleeding to have the filter on the pressure side of the pump but only if the fuel pump has its own strainer - which most do. Experience suggests that if there is air in a filter on the suction side of a lift pump then the likelihood of fuel being pumped by the lift pump is greatly reduced. On my Beauford I now have filters either side of the low pressure pump into the remote swirl pot and both self-bleed in a few miles on the road - we have enough rough roads around here to provide the vibration! A point of information - it is fuel vapour that is in question here, not water vapour. Fuel vapour can be increased by the effects of rising temperature and decreasing pressure as both change the partial pressure and thus increase the rate of vaporisation. Whilst petrol is a highly volatile fuel in its own right, the fact that a carburettor works is a) down to Bernoulli's equation that explains why the venturi provides a lower pressure due to the high air velocity where the venturi contracts, which then pulls the fuel through the jets and b) the low pressure helps to vaporise the fuel. On injection systems the fuel is injected onto the hot inlet valves whence it vaporises before mixing with the incoming air once the valve opens. I cannot say that getting a filter to self-bleed will definitely solve your problems but it would be a very good start, particularly if it only means repositioning the filter in a vertical position - note the recommended flow direction usually shown by a cast in arrow on the casing, the flow going in around the outside of the filter matrix such that when there is a lot of crud in the filter it will be visible. I had this problem back in the 60's when "Know-it-all self" put an in-line filter on my car and had exactly this effect of occasional stopping which miraculously stopped when the filter was removed but at that stage I did not match vapour lock and self-bleeding to the equation. Age and experience does eventually become worthwhile Good luck! Hamish From: [email protected] [mailto:[email protected]] On Behalf Of Mark Sent: 03 October 2013 18:59 To: [email protected] Cc: [email protected] Subject: [Quantum Owners] Re: Car Stopping after ~ 1 Hour So Hamish, just so I understand, your saying that any 'air' space is a possible point for water vapour to form when the system gets hot? Makes sense to me if so. I have a 'cheap' plastic fuel filter just before the fuel pump on my cvh carb 2+2. This is only about half full of fuel at any time (that I can remember), even with the revs up. Do I need to try a better fuel filter? I've never had a problem using these types of filter in the past. Thanks Mark . -- -- You received this message because you are subscribed to the Google Groups "Quantum Owners Group" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/quantumowners?hl=en IMPORTANT NOTE: All information presented herewith is provided on an "As Is" basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor the individuals associated with the Quantum Owners Club or in the preparation of the above information shall have any liability to any person or entity with respect to liability, loss, or damage caused or alleged to be caused directly or indirectly by the instructions contained within this or related message(s). --- You received this message because you are subscribed to the Google Groups "Quantum Owners Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
