Technical 1979 124 spider converting to electric fuel pump

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Technical 1979 124 spider converting to electric fuel pump

Runt

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No fuel from old mechanical fuel pump to carb. Thinking about just converting to electric pump. Worried about constant flow to carb
 
No fuel from old mechanical fuel pump to carb. Thinking about just converting to electric pump. Worried about constant flow to carb
In the past we would simply replace the diaphragm and valves in mechanical pumps and clean out the filters etc.
However if you are worrying about too much pressure at the carb. the electric pump supplier should be able to suggest a pressure regulator or return system back to the tank to manage the higher pressure and flow.
By the way no chance fuel pipe from tank is leaking/blocked/sucking air etc.:)
 
In the past we would simply replace the diaphragm and valves in mechanical pumps and clean out the filters etc.
However if you are worrying about too much pressure at the carb. the electric pump supplier should be able to suggest a pressure regulator or return system back to the tank to manage the higher pressure and flow.
By the way no chance fuel pipe from tank is leaking/blocked/sucking air etc.:)
Just started to look. Could replace mechanical pump but looks like a bitch to get at. Haven’t checked for blockage. As long as I have you, what are your thoughts that if pump is bad I can just connect the two hoses and not need a block plate
 
Just started to look. Could replace mechanical pump but looks like a bitch to get at. Haven’t checked for blockage. As long as I have you, what are your thoughts that if pump is bad I can just connect the two hoses and not need a block plate
Personally after starting as an apprentice in 1969 vehicles from back then were a sight easier to work on than todays.;)
The problem with not fitting a blank is if diaphragm fails it can leak oil from the breather in the old disused pump, although I have seen many like that in the past.
If vehicle hasn't been used for some time the pump diaphragm and valves may have just dried out or be full of rust from old metal fuel tank , in which case a new electric pump will soon die.
I would check condition of any filters and maybe fit a good new one.
 
Personally after starting as an apprentice in 1969 vehicles from back then were a sight easier to work on than todays.;)
The problem with not fitting a blank is if diaphragm fails it can leak oil from the breather in the old disused pump, although I have seen many like that in the past.
If vehicle hasn't been used for some time the pump diaphragm and valves may have just dried out or be full of rust from old metal fuel tank , in which case a new electric pump will soon die.
I would check condition of any filters and maybe fit a good new one.
Should I be worried about to much pressure for the float or will the excess just flow back to the tank
 
Should I be worried about to much pressure for the float or will the excess just flow back to the tank
There would probably need to be a return back to the tank via a pressure relief valve, hopefully the electronic pump supplier can advise.
If you can get a good quality original type pump that would be my choice as they worked well enough from new. So long as any dirt etc . is cleared from system.
 
There would probably need to be a return back to the tank via a pressure relief valve, hopefully the electronic pump supplier can advise.
If you can get a good quality original type pump that would be my choice as they worked well enough from new. So long as any dirt etc . is cleared from system.
It looks like there is a return line back to tank from carb.
 
What pressure should I look for in the electric fuel pump
Many run at 30-45 psi to suit petrol fuel injection systems, but for carbs I would have though 5psi more than enough, that is why you need to talk to the supplier about your needs to prevent flooding and hose damage as well since old systems were never designed for high pressure.
Found this online.:)
"The fuel pump on carbureted cars should supply 3.5 to 4.5 PSI at 2,500 RPM operating tempurature. If you have over this you will run rich, flood, and may have hot starting issues"
 
Many run at 30-45 psi to suit petrol fuel injection systems, but for carbs I would have though 5psi more than enough, that is why you need to talk to the supplier about your needs to prevent flooding and hose damage as well since old systems were never designed for high pressure.
Found this online.:)
"The fuel pump on carbureted cars should supply 3.5 to 4.5 PSI at 2,500 RPM operating tempurature. If you have over this you will run rich, flood, and may have hot starting issues"
Pulled the mechanical pump today and of course dropped spacer and can’t find it. Anyway, I think I will go to electric pump. Saw many videos and wondering if a regulator is necessary. For safety will connect to oil pressure. Will look for pump with 2-4 psi.
 
There would probably need to be a return back to the tank via a pressure relief valve, hopefully the electronic pump supplier can advise.
If you can get a good quality original type pump that would be my choice as they worked well enough from new. So long as any dirt etc . is cleared from system.
 

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Sorry, this is the line that goes back to the tank. When the float closes off has will this keep the carb from flooding
 

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Sorry, this is the line that goes back to the tank. When the float closes off has will this keep the carb from flooding
All you can do is try it, personally I would be happier with a regulated pressure.
A small point if you refit the old petrol pump without the spacer it can cause the operating arm to snap off and drop inside engine as it affects the position/depth of arm onto operating cam. It is there to keep heat from the fuel pump like an isolator but it is also a spacer.
 
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