Our small Chsrity bought an elderly Hymer motorhome for use when we are at shows, street collections etc. It has a fault which we can’t seem to find. We wondered if you knew anyone with knowledge and experience of Mercedes ignition systems circa 1987. The Hymer which is Mercedes 4 cylinder, carburettor, petrol engine based, starts and runs fine. You can rev it up let it tick over etc. all fine. However after 30 seconds or so it cuts out and won’t re-start. Initially we thought fuel. We have checked the fuel system out and tried dribbling fuel into the carb as the engine begins to die to no avail. We fitted a HT spark analyser into No 1 lead and saw the sparks go orange fade then stop as the engine dies. We have replaced the coil, ignition module, run a new LT wire from the battery to the coil, sent the distributor, coil, ignition module to a company in Essex for checking NFF. All to no avail. We are now struggling for ideas. It has been suggested that the shielded wire from the distributor to the ignition module may be the fault. However finding a replacement is proving difficult and I feel we are clutching at straws. We wondered if you or anyone you know might know an enthusiast who might help us?