Hi Daniel,

(Great name!_)

The little vent pipe on top of the tank should have a hose or fuel resistant plastic tubing on it extending sown through the boot floor and down about even with the bottom of the subframe to lead fumes out of the car. With the vented cap, upu do not need a vented filler cap. It does sound like the filter was due to be replaced. That should have helped. Adding Seafoam probably cleaned out the fuel system, including the carb inlet needle valve, which may have been sticking shut. If the fuel in it was stale, that would make starting more difficult. Make sure you have fresh fuel. Maybe another dose of Seafoam wouldn't hurt.

 

Hi , sorry for not replying yet, I did some things, I replaced a cracked hose pump to carb, pump pressure I noticed was working, there is a small tiny vent pipe on top of the fuel tank I run a wire ro make sure ir was free, I havent replace the fuel cap , but will do, I also went under the car and replaced the fuel filtre that was just after the fuel tank at the rear, the plástic was not clear and very toasted, the fuel line pipe lowered at the front because was out of the retainer little clamp and I put it in again, (they are like 3 or 4 of this that keep the line straight under the flor) , after all this I run the car and again still choked out, after that I put some fuel additive I had at hand called seafoam , dont know if all or some of what I did help , next day it started running ok , now I have run it around town a few times and has been ok, also starts faster.

Thanks

Daniel

It is possible the mechanical fuel pump is worn out or failed. It operates via a lever (think pump handle) riding on a cam lobe. The lever could be worn or stuck from age. It has a strong spring in it, and that may have failed. - not likely but a possibility. The diaphragm may have failed from age. If it has, there is a possibility of fuel leaking into your oil sump - check the oil level and smell. (If it is up or the wring smell for your motor oil, do NOT start the engine - the oil may be very dilute and engine damage could occur. The pump has two check valves - in and out. If one has failed, the pumps cannot develop pressure. 

 

If your pump has failed, the fuel will flow by gravity to the carb which is lower than the upper portion of the fuel tank. If the float valve on the carb is open, fuel will flow until it closes. That would give you a short run tome until the carb bowl got low. and would let you limp along in idle. I had the misfortune of a carb inlet needle sticking open with a full fuel tank for winter storage. Over the winter, fuel leaked through the system and into my engine sump. Fortunately, the oil level and bad smell gave it away.

The mechanical pump is fine for your engine, and not expensive. If you do go the electric route, be vary careful about the pump's maximum pressure. Genuine SU pumps work well and at the right pressure, around 4psi. Other pumps may be too strong and will overpower the carb float valve and flood your engine badly. They would need a pressure regulator. 

One thing you could try is when it dies get out and remove the gas cap. If you hear a whoosh of air going into the fuel tank then the tank vent could be blocked and the tank is building up a vacuum that the fuel pump cannot overcome.

Hi , I have a 61 austin mini that has a vanden plas engine 1275, with mechanical fuel pump, lately it starts ok for some minutes runs ok then running it starts choking apears out of fuel, if I let off the throtle it still run for some moment until finally dies, what is strange is that when cold it will start again and run for some time the same again, is this the fuel pump diying ? Or could be other issue? I am thinking of adapting an electric pump

Thanks

Daniel