No fuel to carb

['73bird]

My motor is a 1973 440 from a motorhome. It has a mechanical carter fuel pump.

1. My pushrod is 3.225
2. My fuel pump mounts to the block
3. No fuel is getting to the carb
4. I took the lines from the main fuel line from the tank and also the one to the carb. I stuck the inlet hose in a gas can and the outlet hose into a bottle. No fuel in bottle.
5. The distributor turns when you crank the car.

Any ideas?

 

[miller]

Were the fuel lines, or hoses...primed with fuel? Pump won't work with only air in the lines.

 

[Jcharger]

Clearly priming should make a difference, but my impression was that they were supposed to pull some vacuum even when not primed. I think there are some tests described in the FSM for fuel pumps.

Do you have a pump like a carter m6903? or is it a more generic pump. If it is the m6903 it can be disassembled and reubuilt. I do not know about the others. If it were me and I had one of the others, I would consider the M6903, but might buy an inexpensive replacement if it is clear it is not pumping.

Good luck solving this. I just went through this with the pump pushrod. Yours seems OK, so it is a different issue.

 

['73bird]

My Carter Fuel Pump is the M4589 which is brand new (doesnt mean it couldnt be bad). With the priming that was discussed wasnt that what i was trying to do with sticking the inlet lines into a gas can and then the outlet to a bottle and cranking the car?

 

[khryslerkid]

When installing the fuel pump, did you make sure the pushrod was up against the cam. The rod can slip down and the lever on the pump can miss it.

 

[miller]

With the priming that was discussed wasnt that what i was trying to do with sticking the inlet lines into a gas can and then the outlet to a bottle and cranking the car?

No.
Either the car's fuel lines, or a hose stuck into a gas can, will still only have air to pull.
Is this a new build, or a running car? If the pump is 'just out of the box', it should be primed with fuel, either by real light air pressure (air compressor), for a second or two, to fill the fuel lines. Or, the hose/can bit, get some fuel into the hose, and up so fuel will drain into the pump to 'prime' it.

 

['73bird]

No.
Either the car's fuel lines, or a hose stuck into a gas can, will still only have air to pull.
Is this a new build, or a running car? If the pump is 'just out of the box', it should be primed with fuel, either by real light air pressure (air compressor), for a second or two, to fill the fuel lines. Or, the hose/can bit, get some fuel into the hose, and up so fuel will drain into the pump to 'prime' it.

The car is a running car but the fuel pump is out of the box. Sorry but im confused on your description of priming the pump. An air compressor? Won't that just put air and not fuel into the pump?

 

['73bird]

When installing the fuel pump, did you make sure the pushrod was up against the cam. The rod can slip down and the lever on the pump can miss it.

From everything i have read the pump wont seat/bolt against the block if the rod wasnt against the cam

 

[khryslerkid]

From everything i have read the pump wont seat/bolt against the block if the rod wasnt against the cam

OK. I've known some, years back, that forced the pump when bolting it on, bending the pump leaver. You can inspect looking through the plug for the rod. Just a thought.

I wouldn't think that you have to prime the pump either. I've never primed any new pump when I installed it and it picked the gas right up.

If you can have someone crank the engine, while holding your thumb over the inlet side of the pump, you'll feel vacuum. If not, you could have a bad pump.

Good luck

 

['73bird]

OK. I've known some, years back, that forced the pump when bolting it on, bending the pump leaver. You can inspect looking through the plug for the rod. Just a thought.

I wouldn't think that you have to prime the pump either. I've never primed any new pump when I installed it and it picked the gas right up.

If you can have someone crank the engine, while holding your thumb over the inlet side of the pump, you'll feel vacuum. If not, you could have a bad pump.

Good luck

I pulled it off and reinstalled it. The pump worked by hand. The pump arm didnt look bent. While trying to get the pushrod all the way to the cam i killed my battery so its charging and ill try tomorrow again

 

[miller]

Sorry but im confused on your description of priming the pump. An air compressor? Won't that just put air and not fuel into the pump?

Sorry...didn't explain good enough.
On a new build, fuel lines empty, but gas in the tank...I usually prime the fuel lines/pump, by using 'low' air pressure at the tank fill tube. Only takes a few seconds, the pressure forces the fuel into the lines, up to the pump.
But, if you still have fuel already in the lines, should be good, and the pump should pick up the fuel.
Wondering how you ran the battery down, but no answer needed.
One thing I always do, installing a pump, is turn the motor by hand, until the pump rod is on the low side of the cam. Just makes it a little easier to get the pump into place, since you have to force the pump lever...if that makes any sense.

 

['73bird]

Sorry...didn't explain good enough.
On a new build, fuel lines empty, but gas in the tank...I usually prime the fuel lines/pump, by using 'low' air pressure at the tank fill tube. Only takes a few seconds, the pressure forces the fuel into the lines, up to the pump.
But, if you still have fuel already in the lines, should be good, and the pump should pick up the fuel.
Wondering how you ran the battery down, but no answer needed.
One thing I always do, installing a pump, is turn the motor by hand, until the pump rod is on the low side of the cam. Just makes it a little easier to get the pump into place, since you have to force the pump lever...if that makes any sense.

Car sat without a gas tank for who knows how long. I did everything and took off the pump again. Killed the battery turning the car over trying to get the pushrod in all the way. Found out that carter told me the wrong inlet/outlet on yhe fuel pump. So i reinstalled the pump and switched the lines but battery was dead so i took it back and will try it again this afternoon

 

['73bird]

Car sat without a gas tank for who knows how long. I did everything and took off the pump again. Killed the battery turning the car over trying to get the pushrod in all the way. Found out that carter told me the wrong inlet/outlet on yhe fuel pump. So i reinstalled the pump and switched the lines but battery was dead so i took it back and will try it again this afternoon

Now it gets fuel to carb but now i have to rebuild the carb i guess

 

[miller]

Found out that carter told me the wrong inlet/outlet on yhe fuel pump.

On the Carter pumps, the lower fitting is the inlet side. What kind of carb, and what's it doing, or not doing. Yeah, if it's been sitting dry for awhile, probably needs a look-see.

 

[Jcharger]

I agree, but I would fill the carb with gas and repeat some tests first as is it to see if it works. The fuel delivery might have been your only issue. Hopefully you are up and running with it now.

 

['73bird]

On the Carter pumps, the lower fitting is the inlet side. What kind of carb, and what's it doing, or not doing. Yeah, if it's been sitting dry for awhile, probably needs a look-see.

Its a holley 4412 (small I know but came with the car). Fuel gets to the carb inlet but doesnt go any further. Ive tried pumping the gas 3 long times and nothing. I took out the screw and started the car (with gas in carb) and then sloshed the front end around and no gas came out the screw hole

 

[khryslerkid]

If the float needle is stuck in the carb, it won't let any gas into the bowl.

 

['73bird]

If the float needle is stuck in the carb, it won't let any gas into the bowl.

So take it off and spray it to hell with carb cleaner or rebuild?

 

[khryslerkid]

If you say you're getting fuel to the carb but not into the carb, you'll need to find out why. If there are signs of dirt, corrosion ect. inside, then a good cleaning or rebuild would be instore.

Sometimes, just tapping on the carb, near the needle and seat assembly, will jar the stuck needle enough to let fuel into the bowl. A needle can stick in the seat after sitting for a long period of time.

 

['73bird]

If you say you're getting fuel to the carb but not into the carb, you'll need to find out why. If there are signs of dirt, corrosion ect. inside, then a good cleaning or rebuild would be instore.

Sometimes, just tapping on the carb, near the needle and seat assembly, will jar the stuck needle enough to let fuel into the bowl. A needle can stick in the seat after sitting for a long period of time.

So take a phillips screw driver and put it on the screw in the carb and lightly tap it with a hammer