More on won't start
Posted: Sun Mar 07, 2021 2:53 pm
I found it interesting to read on the discussion board that a dry fuel pump is unable to self prime and that a hand priming pump will solve the problem easily. It was also recommended that before a long term layup the petrol tank should be filled to the brim as this puts the fuel level above the pump (assuming a level a garage).
I have not seen it stated in any maintenance manuals that a dry pump will not self prime, however I did discover this the hard way when I had to replace the metal fuel pipe section that goes over the top of the rear axle, when it developed a crack in one of the bends. It did take me some time to discover this because at this point the pipe work is above the top of the petrol tank so petrol was not leaking even when the tank was full and the car was standing in the garage. It only became a problem when the engine was running and air was drawn into the pipe. After I replaced the pipe I could not get the pump to draw petrol from the tank. Initially I changed the pump but this was not the problem so in the end I decided to prime the pump or to be correct I disconnected the inlet rubber hose from the pump and sucked petrol, primed the petrol pipe work from the petrol tank, having done this the engine started up after a few turns. More recently my son in law, Matt Cotton, replaced the petrol line on his auto sprint and he found the car would not start but once I told him to prime the fuel line the problem was resolved.
I do not know if the pumps would have drawn petrol, if I had left the engine turning over for a long time and I am assuming that the Professional mechanics in the group will be muttering did you not know there was a need to prime the system, but for the amateur mechanics in the group like me I decided to go into print.
With the introduction of E10 fuel and with the start of the classic car season approaching I assume a number of owners will be replacing the rubber hose sections that join the various sections of metal petrol pipe work together under the car so you have been warned you may need to prime the fuel line having replaced the hose sections so you may like to purchase a hand priming pump before you start. If you are considering replacing the rubber hoses, for info the pipe work under the car has an outside diameter of 5/16th inch and from the pump to the carbs it is smaller only having an outside diameter of ¼ inch. You may find that you can’t reuse the old spring type clips because I found that the outside diameter of the replacement rubber hose is smaller than the original. I also believe that the replacement rubber hose needs to be manufacture to meet SAE30R14T1 but I believe that there is a lot of fake hose about so be careful from where you purchase the hose from.
I have not seen it stated in any maintenance manuals that a dry pump will not self prime, however I did discover this the hard way when I had to replace the metal fuel pipe section that goes over the top of the rear axle, when it developed a crack in one of the bends. It did take me some time to discover this because at this point the pipe work is above the top of the petrol tank so petrol was not leaking even when the tank was full and the car was standing in the garage. It only became a problem when the engine was running and air was drawn into the pipe. After I replaced the pipe I could not get the pump to draw petrol from the tank. Initially I changed the pump but this was not the problem so in the end I decided to prime the pump or to be correct I disconnected the inlet rubber hose from the pump and sucked petrol, primed the petrol pipe work from the petrol tank, having done this the engine started up after a few turns. More recently my son in law, Matt Cotton, replaced the petrol line on his auto sprint and he found the car would not start but once I told him to prime the fuel line the problem was resolved.
I do not know if the pumps would have drawn petrol, if I had left the engine turning over for a long time and I am assuming that the Professional mechanics in the group will be muttering did you not know there was a need to prime the system, but for the amateur mechanics in the group like me I decided to go into print.
With the introduction of E10 fuel and with the start of the classic car season approaching I assume a number of owners will be replacing the rubber hose sections that join the various sections of metal petrol pipe work together under the car so you have been warned you may need to prime the fuel line having replaced the hose sections so you may like to purchase a hand priming pump before you start. If you are considering replacing the rubber hoses, for info the pipe work under the car has an outside diameter of 5/16th inch and from the pump to the carbs it is smaller only having an outside diameter of ¼ inch. You may find that you can’t reuse the old spring type clips because I found that the outside diameter of the replacement rubber hose is smaller than the original. I also believe that the replacement rubber hose needs to be manufacture to meet SAE30R14T1 but I believe that there is a lot of fake hose about so be careful from where you purchase the hose from.
