Starting the Plymouth

[Kaos]

I finally got a key cut today and trying to start it turns over great and with starter fluid it will run till it burns it all.  There is a clear fuel filter just before the carb and I can see gas collecting in the bottom of the filter but it never fills up.  I have on a few occasions had the filter half full but once the car burns the fluid and dies the gas goes back down.  Question is how does the pump work?  Could the fuel cap not sealing good cause it to lose pressure and drain or could I have a hose somewhere clogged or leaking?  

 

Things to try?  I have a service manual on the way but not arrived yet so I am kind of scratching my head.

 

Also I noticed the battery cables are getting hot like to the point they started to smoke a little once.  Normal or something else I need to check?

 

Thanks for any help

 

David.

[JerseyHarold]

If you have thinner 12 volt battery cable that's probably why they are getting hot with repeated cranking.  if you still have a 6 volt electrical system, you should have thick battery cables ('0' gauge or thicker) to handle the higher current.   The fuel pump may be weak after sitting a long time.  Try removing the inlet hose from it and connecting a rubber fuel hose connected to a can with fresh gas.  if the car starts and runs with this set-up, you probably have bad gas.  Hope this helps.

[TodFitch]

Battery cables shouldn't get very warm, certainly not warm enough to smoke.

 

Pump works off of an eccentric on the camshaft. Basically a diaphragm and a couple of check valves. Once you have the manual you'll see the fuel pump tests. Basically there is a pressure range on the output and a flow rate. Flow is tested by removing the outlet connection and directing it to a jar and then seeing how much gas is pumped in a given number of stokes (5 to 6 oz. in 15 pump strokes). Pressure at the carburetor should be 4 to 5.5 lbs. (Both those numbers from the '48-54 factory service manual.)

[Kaos]

I emptied the tank and added 4 gallons of fresh gas to it. I also put a very small amount of mystery oil in the gas. Think it called for 4 ounces to 10 gallons I maybe put an ounce in.

[Kaos]

There is a knob that is installed to the left of the key switch that turns and has a light that comes on in the center when on.  Any idea what that does and would it be added?  There are several switches that were added to the car but no idea what they do but I am rather curious what this one does.  I did find one of these switches turns on a fan below the dash on the passenger side.  The knob in question is located to left of the switch off the chrome does appear to be original but I'm just not sure.

Edited July 1, 2015 by Kaos

[greg g]

Remove the fuel hose from the inlet side of the fuel pump. remove the gas cap, put some compressed air through the line toward the tank, till you hear bubbles in the tank.  There is an oilite (sintered brass) filter on the pick up it can get clogged with rust, the air will clear it.  With the fuel line disconnected from the carb, direct it into a suitable container.  Pull the coil wire and have an assistant crank the starter.  You should be able to count fuel pulses coming from the pump.  If you have 8 to 12 ounces for 10 or 12 pulses you have sufficient fuel flow to run the engine.  If not the pump may be clogged with debris also.  removal and cleaning of the lower chamber inlet screen may be needed.

[Young Ed]

That knob in the middle sounds like a heater knob. The light got brighter as the speed for the fan increased

[Labrauer]

Does the fuel pump have a glass bowl on the bottom of it? Mine does and it is always full but the inline fuel filter is like half full while running at a slow speed but when the engine is raved up and slowing back down the filter fills up with gas how ever it goes back to half full after the car sits. Take the line loose on the carb and turn the car over a few revolutions and see what kind of flow you have coming out of the line. Could be that the diaphragm in the fuel pump has a small hole in it making it loose it's prime. You might also check the carburetor pump piston to see if it has dried out and not able to pump gas. As far as the battery cables getting hot and smoking that is a no no. Check the size of the cables as a 6 volt car needs a cable of no less than 0 gauge and probably would be ever better double 0 gauge and if your cables are of one of these two sizes I would look for a short or a loose connection between the battery and the ground or make sure the cables are hooked up right to the engine. The guy's that have answered your questions before me have great ideas of what to check and do also so it is just a trial and error thing. Good Luck.

[Mark Haymond]

The cap on the gas tank neck should not be a tightly sealed one. This year car needs to let a small bit of air into the tank when the fuel pump is sucking a small bit of fuel out from the bottom of the tank. Since your car has set a long time I doubt the cap has a tight seal anyway.

.....

If you discover the fuel pump is defective you may be surprised that you can buy a new one at a modest price from the major car parts on line stores.

.....

My old car tip: don't throw away any old parts, working or not, or screws or bolts or clips or ANYTHING. They may come in handy a year or two later for their part number, or size fit or such. Just saying.

[RobertKB]

My old car tip: don't throw away any old parts, working or not, or screws or bolts or clips or ANYTHING. They may come in handy a year or two later for their part number, or size fit or such. Just saying.

 

Never truer words spoken!! It's when you throw them away that you will find you need them shortly afterwards. Been there and done that.

[Ulu]

The cap on the gas tank neck should not be a tightly sealed one. This year car needs to let a small bit of air into the tank when the fuel pump is sucking a small bit of fuel out from the bottom of the tank. Since your car has set a long time I doubt the cap has a tight seal anyway.

.....

If you discover the fuel pump is defective you may be surprised that you can buy a new one at a modest price from the major car parts on line stores.

.....

My old car tip: don't throw away any old parts, working or not, or screws or bolts or clips or ANYTHING. They may come in handy a year or two later for their part number, or size fit or such. Just saying.

 

If I suspect poor fuel flow on traditional fuel systems, the first thing I do is remove the gas cap & if that works I check the vent hole. It's the easiest thing to check & they do plug up sometimes. This applies to all pre-charcoal canister vehicles.  (If you have a canister, you must have a sealed gas cap, or else the canister will never purge.)

Edited July 1, 2015 by Ulu