Topic: 1947 Ford Starting Problems


Bill E Bob    -- 01-23-2018 @ 2:09 PM
  Need some guidance with my assumptions.
I'll preface this with current situation:
1. Starter a bit slow--to be rebuilt.
2. Carb rebuilt with ct Ken kit.
3. Once started, runs fine.
4. New fuel pump.
Problem:
After sitting for extended periods, have to prime before it will start. Once primed, starts and runs fine. Starting after sitting a short time, have to hold accelerator to floor to get enough air in to start.
My "assumption":
A leak around the power valve that allows the carb. bowl to drain after engine shutdown.
IF that is the case, is there a recommended fix. If NOT, any guesses as to what the problem is?
Any assistance is Most appreciated.




cliftford    -- 01-23-2018 @ 7:33 PM
  Pull the dipstick and see if it smells like gas. If so, the power valve gasket is probably leaking. Also check the fuel pump for excessive pressure, should be about 2.5 lbs. You could add a pressure regulator if needed. Also check float level , needle valve and float making sure it is not binding. See previous posts on this subject.


42wagon    -- 01-24-2018 @ 3:13 AM
  The problem of having to reprime the carb after sitting for sometime seems to be a common problem since there are no check valves to keep gas from running back down the line to the tank. Others have resorted to an auxiliary electric fuel pump to reprime the system. I can't offer any advice regarding your other problem.


supereal    -- 01-24-2018 @ 8:28 PM
  That problem is caused by the evaporation of the gas in the carb bowl from engine heat after shutdown. Many of us use an electric pump to reduce cold cranking, and a QuickStart diode circuit to compensate for low system voltage due to starter draw. As to gas running back to the tank, both the position of the float needle in the carb and the check valves make that unlikely.


TomO    -- 01-25-2018 @ 12:25 PM
  Bill, I agree that your guess is probably correct. A leaking power valve gasket will also cause problems with idling as the mixture will be too rich.

I use the power valve gasket with the triangle cutout and tighten it hand tight then add 1/6 turn. Fill the bowl with enough gas to cover the power valve and let it sit overnight. If the gas level is lower the next day, tighten 1/6 turn more. Repeat until either the leak is fixed or you have added more than 1/2 turn. If you have to add more than 1/2 turn, the bowl seat or the power vaolve is bad and need to be repaired.

Tom


Bill E Bob    -- 01-25-2018 @ 1:47 PM
  Thanks Tom. I pulled the carb, checked all the jets, removed the power valve and noticed the threads being a bit rough, sooo, I wrapped the threads with some teflon tape, taking care not to cover any orifices nor bind the spring and reinstalled the valve, however, did not think to do a leak test before reinstalling. Will let the unit sit for some time and see what happens. Will post results.
William(carbfounded)Brown


cliftford    -- 01-25-2018 @ 2:33 PM
  Bill, using Teflon tape is not usually recommended for carb. work. As TomO suggests, get a good gasket to go between float body surface and the power valve. This is the area that needs to be well sealed.


Bill E Bob    -- 01-25-2018 @ 3:28 PM
  Ok. will do.
Thanks
Bill


TomO    -- 01-27-2018 @ 8:39 AM
  The Teflon tape will shred and plug up the passages in the carburetor. I would not run the car with Teflon tape or pipe dope on the threads. The power valve threads are not sealing threads, the gasket does all of the sealing.

White Teflon tape is made to seal water leaks and should not be used anywhere on a 32-53 Ford, Lincoln or Mercury.
Yellow Teflon tape is only for natural gas, not gasoline.

Tom


Bill E Bob    -- 01-27-2018 @ 5:33 PM
  Removed!
Thanks


TomO    -- 01-28-2018 @ 8:56 AM
  Slow starter could be low battery or connections. Do a search for 'Voltage drop' and you should come across one of my posts for checking out the starter circuit. If that doesn't work, search on 'slow starter'. I may be able to get on a full size keyboard in a couple of days and if you have not found it by then, I will search for one of my posts.

Tom


Bill E Bob    -- 01-28-2018 @ 9:15 AM
  Well, all new cables (including engine to firewall), new solenoid, fresh battery, cleaned battery connections, dielectric grease. complete rewire. Starter Bendix weak so assuming starter could use a tune up. Will make sure starter to engine connection clean to insure proper grounding, but still think starter rebuild in my future.
Thanks
Bill


cliftford    -- 01-28-2018 @ 12:21 PM
  this would be a good time to install a diode quick start system as mentioned above. All you need to do is run a circuit from the starter side of solenoid through a diode to the batt. side of coil. This will make it start easier and save wear and tear on the starter and battery.


MG    -- 01-28-2018 @ 12:55 PM
  cliftford > Maybe supereal will post his schematic of the circuit you describe....


ken ct.    -- 01-28-2018 @ 1:41 PM
  You didn't tighten the PV enough I have to assume. The PV that was in the kit have never had a problem with the nylon gasket and have sold and used hundreds of them that way. ken ct call me if you wish. 1-203-260-9780


TomO    -- 01-29-2018 @ 10:14 AM
  Just because you have new parts doesn't mean that they are working correctly. A friend has a slow starter and after looking at the cables, it was determined that he had 12 volt cables. He picked up a set of 6 volt cables from NAPA and still had the slow starter. We did a voltage drop test and found that one of the new cables had high resistance. Replace it and then his starter turned over his engine nicely.

The most common cause of a slow starter is resistance in the circuit from the battery to the starter. To check for this connect a voltmeter COM or black lead to the NEG battery post and the + or red lead to the terminal on the starter. Operate the starter with the ignition off and read the voltmeter. It should read 0.3 volts or less. If it reads more than that, move the red lead to the next connection toward the battery, this should be the starter switch or solenoid, repeat the test and look for a reading of 0.2 or lower. If it is more than that, the cable from the battery should be replaced.

When you have determined that the cable and connections on the NEG side are all good, check out the grounding circuit by connecting the red lead of the meter to the POS post and the black lead to one of the starter mounting bolts. Operate the starter and read the meter. It should show 0.1 volts or less. If it shows more, remove the starter from the oil pan and clean the mounting surface of the starter and the pan. Repeat the test. If it is still more than 0.1 volts replace the ground cable from the motor to the body and the ground cable from the battery to the frame. Make sure that the area where the ground cable is connected is clean, with no rust or corrosion.
To check the battery, connect the voltmeter across the posts of the battery and operate the starter. The volt meter should read above 5.0 volts. If it is less than that, your battery does not have enough power.

If all of the above tests are satisfactory, either your starter is bad or the engine is too tight.

Tom


Bill E Bob    -- 01-29-2018 @ 11:31 AM
  Good information. Will follow directions and see what transpires.
William(combating ignorance one forum post at a time)Brown


Bill E Bob    -- 01-30-2018 @ 10:51 AM
  UPDATE:
Tried suggestions from Tom RE: starter.
All cables checked out OK. So we have a sick starter OR operator failure.
Today's start from cold took awhile, but she finally lit (without priming), so I'm leaning toward drain back to the gas tank, OR I'm so used to the 12v instant start that my expectations are too high.
Will continue on with measuring fuel pump pressure and, if necessary, will add pressure regulator.
At this point, have eliminated power valve gasket leakage as a problem, so will continue my investigation. Expecting possible supplemental 6v electric fuel pump or flexible fuel line connection with check valve. We'll see.


cliftford    -- 01-30-2018 @ 12:07 PM
  Bill, here's one more thing to try: temporiarly bypass the ignition resister with a jumper and start engine. This gives full voltage to the coil. If it starts easier, you need to install the bypass circuit. I might add, a 6 volt system in good condition will start an engine as fast as a 12 volt.


Bill E Bob    -- 01-30-2018 @ 12:34 PM
  Cliftford,
Will give it a try. She does start immediately after warmed up, just slow to start when cold, but, since I'm pretty much a noob with these old Fords, who knows?
William(with a LOT to learn)Brown


TomO    -- 01-31-2018 @ 9:19 AM
  When someone can show me how gas can get past the needle valve in the carburetor, both fuel pump valves and overcome the pressure of the gas in the tank, I might consider that gas could drain from the carburetor to the tank. Gas will evaporate from the carburetor bowl after several days, but if the bowl is empty after sitting for less than a week, there is a leak.

A quick check for a leak is to let the car sit for a few days and then remove the air cleaner and operate the accelerator. You should see 2 strong streams of gas from the jets. If you do not see these, there is something wrong with your carburetor. You should also check your spark plugs and exhaust pipe for black sooty deposits. These are an indication of a rich mixture that may e caused by a carburetor leak.

Each carbureted engine has its own starting procedure. Some of them flood very easy and others need a shot of gas and a full choke.

Try pulling the choke out most of the way next time you do a cold start. If it still takes a lot of cranking to start it, try pressing the accelerator pedal once with the choke out. Most Fords will start with one of the procedures. Be ready to push the choke in slowly until the engine smooths out. When the engine temp moves from the cold rest position, push the choke all the way in.


Tom


Bill E Bob    -- 02-05-2018 @ 6:53 AM
  Update:
Add'l info from Len47Merc (via TomO) suggested possible sediment bowl gasket leak so removed sediment bowl. Attempted to reverse gasket and it crumbled, so now a new gasket after removing fuel pump, cleaning gasket surface, discovering inappropriate fuel pump inlet fitting and reinstalling fuel pump with added clear plastic gravity flow fuel filter BEFORE fuel pump. This, to determine if fuel will stay in the line upon shutdown. Won't go into detail RE: missing the fuel pump rod when reinstalling fuel pump. At any rate, got it restarted, ran till warmed up, shut her down and the next day no fuel in the gravity flow filter indicating to me drain back to the tank, which further indicates an air leak or something similar. At any rate have a new fuel pump and push rod on order.
Now for a new question: What is the size of an OEM fuel line from tank to firewall and from fuel pump to carb? Currently sporting 1/4" line from tank to firewall and pump to carb with clamped 1/4" hose as flexible fitting. (Yeah, that part's wrong) So, since going for original am willing to replace from tank to carb if necessary (to include proper flexible fitting without the in-line filter).
Apologies for the long post, but figured a follow up might be helpful.


42wagon    -- 02-05-2018 @ 7:46 AM
  Bill
Fuel drain back must be a fairly common problem. At least common enough that someone makes a fuel hose with a check valve in it. If you have the latest V8 Times check the ad on page 106. "Fuel Hose FH-2V Built in check valve $40ppd Check Valve in pump fitting stops fuel drain back and makes starting easier." So sez the ad. I don't have one of these but am certainly thinking about it before the next summer driving season. If you get one and it works post the result. It just may be the cure for your problem.

Ted


TomO    -- 02-05-2018 @ 9:33 AM
  Even if the gas in the line evaporated or settled back to the tank level, there should be enough gas in the carburetor to start and run the engine for a minute or so and if you do not have any air leaks on the input of he fuel pump, it should prime itself and fill the carburetor bowl.

The 47 fuel pump has a glass sediment bowl and you can install a filter in the bowl. The inline filters can be a source of air leaks on the input side of the pump, so you may have added a problem.

Think back to your high school science class and history class. The ancient Egyptians used water levels to build their pyramids, because a fluid always tries to equalize the level. The tank line on a Ford is "L" shaped with the short leg of the line leading to the fuel pump. The level of gas in the line leading up to the flex line will be the same as the level in the tank, if air is allowed to enter the line. The input valve to the fuel pump will stop holding vacuum after about 1 minute.

If you have a full tank, the level of the fuel at the flex line connection will be very close to the level in the tank. As the tank becomes closer to empty, the level in the line will also drop after the vacuum from the pump is lost. This has been going on in all Ford cars since 1932 and the one way valves were not needed then or now.

Where the vacuum leak on the input side of the fuel pump comes into play is when the fuel pump needs to prime itself. The pump sucks gas up the line, and if there is a vacuum leak or the input valve on the fuel pump is bad, the gas will drop back to almost its previous level. This will happen on each cycle of the pump and eventually it will prime itself. When you pour gas in the carb, the engine starts and the pump runs faster allowing it to overcome the leak down.

What it all boils down to, is you may have a leak in the carburetor and a leak at one of the connections to the input side of the fuel pump. Another item to consider is that the fuel line from the tank may be rusted almost closed on the inside.

The original fuel lines are 1/4" copper coated steel lines. You can purchase quality lines from Roy Nacewicz or Narragansett reproductions. Some of the other lines sold are just plated on the outside.

Tom


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