I have a 20r with a 32/36 weber carb and I have a problem. I think its with the fuel pump. First of all, It cranks but no fuel is going into the carb. It starts on a dime when I put fuel straight into the carb. My fuel filter is good.

How do you replace the fuel pump? Is there any testing? Is it located in the tank? How do you remove the fuel tank? Etc... I just need help!

 

how old is your carb???
is it rebuilt
you have a mechanical fuel pump located on the head...
its just 2 bolts holding it down.. try change it....
even if the fuel filter looks good try to check if its clogged/dirty

 

The fuel pump on your 78 is an electric pump, located inside the fuel tank, the fuel tank unbolts at the ends of the tank, remove the hoses, unplug the wire connector for the pump/gauge, and drop it down and out. The pump is mounted on the fuel pickup/sending unit under the round cover on the top of the tank.
The pump is wired up through a relay and also to the oil pressure sending unit, won't turn on until the engine has oil pressure.
You can unplug the oil sender wire from the engine next to the oil filter, turn the key on and the pump if good should operate, if not, you can test the wires for power to see if that might be the problem, if you don't feel like dropping the tank a universal inline electric fuel pump can be mounted preferably back by the tank, and spliced into the fuel line and your good to go, it will still draw through the old pump inside the tank. Good luck

 

there is also a possiblilty that your weber has a fuel cut solinoid.

its on the front pass side of the carb near the top, with a obvious electrical connector on it.

you'll need to run a "key on" hot lead to it.

 

Could you make it more specific on this? I dont want to drop my tank down.

 

i didnt know that...
now i learned something new..
thanks

 

I was having a similiar problem with mine (22r), I had the following replaced:

Carb (weber 32/36)
Fuel pump
fuel filter.

And it was still cutting out. Come to find out the problem was some clogged fuel lines, (one of) the fuel line (s) coming from the tank to the carb was blocked and only delivering 40% or psi (not sure excatly) flow, my fabricator blew all the lines out, installed a high end clear fuel filter (when the truck starts now, the inside of the fuel filter looks like a mini jacuzzi lol) and it runs like a champ now, no problems and has a-lot more power than before, I'm not really into speed and power, but its pretty cool to press down the pedal and it just takes off, some more engine power mods may be in my future one day.

I hope this helps.

 

there is also a one way fuel valve that is usually located near the tank (from factory) mine was rooted, so i swapped it out and my truck runs heaps better
one of those stupid little things

 

Same happened to me. Turned out to be the Fuel Pump relay. You can either get a new one, and replace it; or do what I did, and rewire your fuel pump to a switch. Fixes the problem, and assuming the switch isn't obvious, instant theft-proofing.

Re-wiring the pump required dropping the tank, testing the pump (battery charger and a bucket of gas) and running a wire from the battery, to a fuse holder, to a switch, to the pump. The pump is grounded to the fuel tank on one of the screws (sounds safe, huh?), so no return wire needed.