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TR2/3/3A Fuel Pump???

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Skidude

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Recently had my carbs rebuilt. Since the rebuild - if the car sits for more than a couple of days - it is very difficult to start. It's like the car has kept no fuel in the bowls - like it has to pump gas from the tank, through the lines, the pump to the carb bowls until they finally fill up and then the car will sputter and start.

Never did this before - and there are no fuel leaks I can find anywhere.

Could this be a fuel pump problem that is causing some sort of vacuum that is sucking the gas back to the tank?
 
You can find check valves at any hardware store or auto parts supplier.
Just make sure they are fuel safe.
 
Alcohol fuel will dissapate from a fresh stopped engine and evaporate. Pull fuel and see if fuel is pumped at start. If fuel pump has a pump handle on it prime first, then see hiw it starts.
 
Check the rubber gaskets where the fuel bowl attaches to carburetor. They can be difficult to get sealed. There could be a very slight leak threre. Touch the bolt holding the bowl looking for any signs of gas.

David
 
To answer your question..."no", fuel cannot suck out of the bowls. It just evaporates. That's also why the OEM pump has the manual lever. If your car sits more than a week, you can save a lot of cranking by using the manual pump lever. If you don't feel like popping the hood to manually pump, then consider the long cranking normal after a long sit.
 
I'm with you, Geo. I used to religiously pump up the fuel bowls...but the last few years I just let them crank up.
 
This has always been a big issue in early Porsches. One common solution is to insert a priming bulb into the fuel line--like one of those thingies used with outboard motors, and use it to prime the carbs before starting. I think that looks stupid, but it's done a lot. Another is to include an electric fuel pump, which is used only for priming. Again, that makes no sense to me--if you have the electric pump, why use the mechanical one at all?

My solution in the Porsche 912 and in my TR4A is to have an electric fuel pump that has a rated pressure a little higher than the old mechanical one (say, about 6 PSI) and to use a Holley regulator to adjust the pressure to a nice, consistent ~2 PSI at the carbs. If the car has not been run for a while, I turn on the ignition, wait a minute for the float bowls to fill, and start the car.
 
Electronic fuel primer is good.
 
I believe the chokes are not set correct. Pull the choke out and then look down and see how far the jet pulled down. The front jet depending where you live needs to come down at least Ā¼ inch when the joke is pulled.

steve
 
Iā€˜ve begun to pump the fuel pump lever nowadays if the car sits for awhile. Any idea how many times I should do this? Jim
 
You should be able to feel when the bowls are full and the float valves close. You can't hurt anything by pumping too many times but 7 or 8 strokes should do it.
 
A video showing proper procedures, actual start begins at 8 minutes in.

 
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Just as easy as a British Car tuneup. 100 mph for 3 miles after warmup, cool down and return to barn. Keeps them clean and ready.
 
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