SU fuel pumps.
Posted: Thu May 07, 2015 11:36 pm
Like electronic ignition it seem standard to fit the SU pump with electronic because SU fuel aren't reliable.
A new SU pump has a life of 15 years or 100k miles before overhaul and once properly overhauled will do it all again.
Thats quite reliable.
Plus electronic ones do go wrong and hitting it wont get it going again.
The usual fault is dirty points. If the pump will start with a smack. Disconnect and plug the feed. The pump will run out of petrol and click fast. Leave running for 10mins. Feel outside to make sure it doesnt get too hot. As the points open and close they slide across each other in a cleaning action. This is sometimes enough to save a strip down get you home.
Pumps suck
The importantance of the pipe from the tank to pump is that the fuel must flow freely. If not the pump will stall with points closed. Inside the coil is a swamp resistor if this burns out the pump will eat points. So great care should be taken with filters in the suction side. The pump is designed to handle small debris so brass mesh filters are fine, paper element type can cause problems.
Makers of cars generally dont want their product to breakdown and fit good petrol filtration systems so dont fit extra filters. Do not fix what isn't broke.
Overhauling SU pumps. There is a lots of info on the web just follow the instructions. Parts are not expensive often a carborundum stone fixes the points and thats all that is needed. Easy cheap diy no problem.
Correct colours are black for coil and natural aluminium finish for valve body. Also dont forget the breather pipe.
My 1974 Shadow has a double pumper under the drivers seat. Double pumpers look nice in a pump way.
To test I fit a clear tube to outlet of pump and see how high the pump will pump petrol up the clear tube. Then refer to specs.
Morris Minors have a su pump mounted on the left hand fire wall above the level of the carb. Like an auto vac. These pumps suck harder and deliver from the pump by gravity. These pumps are different. Also the suction line from the tank must be even more free flowing..
My wife used open the glove box of my Minor and thump the back of the glove box to get the pump going, when one has spent all week fixing cars ones own car never gets fixed. Thats mechanics for you. Happy days.
Regards
Bob Reddington.
A new SU pump has a life of 15 years or 100k miles before overhaul and once properly overhauled will do it all again.
Thats quite reliable.
Plus electronic ones do go wrong and hitting it wont get it going again.
The usual fault is dirty points. If the pump will start with a smack. Disconnect and plug the feed. The pump will run out of petrol and click fast. Leave running for 10mins. Feel outside to make sure it doesnt get too hot. As the points open and close they slide across each other in a cleaning action. This is sometimes enough to save a strip down get you home.
Pumps suck
The importantance of the pipe from the tank to pump is that the fuel must flow freely. If not the pump will stall with points closed. Inside the coil is a swamp resistor if this burns out the pump will eat points. So great care should be taken with filters in the suction side. The pump is designed to handle small debris so brass mesh filters are fine, paper element type can cause problems.
Makers of cars generally dont want their product to breakdown and fit good petrol filtration systems so dont fit extra filters. Do not fix what isn't broke.
Overhauling SU pumps. There is a lots of info on the web just follow the instructions. Parts are not expensive often a carborundum stone fixes the points and thats all that is needed. Easy cheap diy no problem.
Correct colours are black for coil and natural aluminium finish for valve body. Also dont forget the breather pipe.
My 1974 Shadow has a double pumper under the drivers seat. Double pumpers look nice in a pump way.
To test I fit a clear tube to outlet of pump and see how high the pump will pump petrol up the clear tube. Then refer to specs.
Morris Minors have a su pump mounted on the left hand fire wall above the level of the carb. Like an auto vac. These pumps suck harder and deliver from the pump by gravity. These pumps are different. Also the suction line from the tank must be even more free flowing..
My wife used open the glove box of my Minor and thump the back of the glove box to get the pump going, when one has spent all week fixing cars ones own car never gets fixed. Thats mechanics for you. Happy days.
Regards
Bob Reddington.
