Fuel Pump Or Vapor Lock?

[wdoland]

6 cylinder spitfire ran great then sat for about an hour. Started it up and it stalled. Could not see any gas in the filter. Did I lose the prime? It's pretty hot today, is it vapor lock? Might be time to switch over to electric pump.

[greg g]

Next tine it happens, treat the engine as if its flooded.  Slowly push the gas pedal to the floor, hold it wide ope then engage the starter.  If the car starts, you are likely suffering from fuel percolation due to under hood heat and the tendency of modern fuel to absorb heat, expand and overfill the float bowl flushing it into the manifold where it pools.  Then the residual pressure in the pump refills it till the lie from the pump to the carb empties.  If it starts ad runs when started as above, reset your float level down a 32nd or two.  Thie will leave room int he float bowl for some expansion, and keep the needle and seat valved closed instead of dropping to allow more fuel in to heat up and flow over again.

[wdoland]

Had my son spray starting fluid in the carb while I drove it up the driveway (really steep) into the garage. I could see little gas in the fuel filter. About 1/2 full. Shouldn't that be full? Won't stay running on it's own. I'll see what happens tomorrow after work when it cools down. At least I got it in the garage.  

[greg g]

Take a close look at the hose between the frame and the fuel pump inlet.  they will some time look great onthe outside but be mushy and collapse under vacuum, cutting of fuel flow. 

[TodFitch]

Starts and runs for a minute then dies? That sounds like it might be vapor lock (starts on the fuel in the carb bowl but the pump isn't pumping so the carb runs dry after 30 seconds or a minute).

 

If it happens again, pour some room temperature water on the fuel pump. If it starts up pretty quick (will need a few strokes of the pump to get gas to the carb) and then runs okay, then its vapor lock. And you have your work around. If it doesn't start up then it's probably something else.

 

Do you have the heat shield between the exhaust manifold and the fuel pump?

[wdoland]

Well I guess it's not vapor lock. Went out this morning and it wouldn't start. Nice cool morning in the 60's. No fuel in spraying in carb but there is fuel in the filter and glass bowl.  I did see gas around the pump where the gasket is. (right in the middle of the pump) 

[Don Coatney]

Have you pulled and inspected the spark plugs?

[wdoland]

Plugs and wires are new. Should I pull them anyway? If so, what am I looking for?

Shouldn't I see gas spraying in the carb when I work the throttle linkage?

Edited August 14, 2013 by wdoland

[greg g]

If gas is leaking out, air is leaking in.  Air is not a friend of a mechanical fuel pump.  It wants to move liquid.  Start with addressing that.  Then pull the top of the carb and check the condition or the leather bellows on the acc pump piston.   Likely it it dried up or chewed up by ethanol.  They are available without buying a carb rebuild kit. While the top of the carb is off you can address your float level.

 

As Don C mentioned pulling the plugs and checking your firing conditions can tell you a lot about the health of your engine.  Do a search of reading spark plugs on the internet, you chould be able to pull up several sites that show pictures of plugs and describe their condition as they relate to a properly runnnig engine.

[TodFitch]

Well I guess it's not vapor lock. Went out this morning and it wouldn't start. Nice cool morning in the 60's. No fuel in spraying in carb but there is fuel in the filter and glass bowl.  I did see gas around the pump where the gasket is. (right in the middle of the pump) 

 

Right in the middle of the pump? That sounds like the diaphragm, not a gasket.

 

If gas is leaking out, air is leaking in.  Air is not a friend of a mechanical fuel pump.  It wants to move liquid.  Start with addressing that.

 

Definitely. Sounds like a new pump or, my preferred solution, a fuel pump rebuilding kit, is in order. Antique Auto Parts Cellar (a.k.a. Then and Now Automotive) has kits and they aren't that hard to rebuild.

 

Also, if the diaphragm went out, there is a good chance you've got some gas mixed into your oil. So if thats the case you'll want to do a oil change when you fix the problem.

[wdoland]

Thanks for all the quick replies. I will pull the pump and rebuild or maybe look into an electric pump. I'll let you know the progress.

[Don Coatney]

It does not matter if your plugs were new yesterday. If your engine is flooded the plugs will foul and the engine will not start.

[wdoland]

You were right, Don. Took the plugs out and they were all carbon fouled. Cleaned them up, put them back in and still wouldn't start.  Sprayed a little starter fluid down it's throat and it started and instantly quit.

I ordered a new fuel pump today from Rock Auto (then found it was cheaper on Amazon...Doh!!) Figured by the time I get a rebuild kit, for a few dollars more, I could have a new pump. Now I'll have a backup. Hope that solves the problem with getting gas. 

Now a question about the spark plugs. Since they were only about 2 weeks old, do you think I need hotter plugs or just running too rich. ? I replaced what was in there which were Autolite 306 

[Don Coatney]

What is the general condition of your engine compression, etc?

[wdoland]

I have no idea but the last owner had the engine rebuilt and said there was about 500 miles on the engine since the rebuild. Starts right up with a squirt of starter fluid. Just cuts out after a few seconds.

[Don Coatney]

In my opinion the use of starting fluid is not a good idea. The burn rate is much faster than gasolene, it may cause severe detonation, and it will wash away all cylinder lubrication possibly leading to piston ring galling. But as I said that is my opinion.

 

I do suggest you do a compression check to insure engine health. What are you using for an air filter? Prior to this latest no start issue how did your engine run? How many miles have you driven it?

 

[desoto1939]

After installing a new fuel pump and also the new rubber fuel line. Then let us know if the car starts.  If the Fp is now working right now even with squirting Starting fluid into the carb it will only run on the small amt of starting fluid that has atomized and gets to the appropriate cylinder to fire over. But since the fp is not sending any fuel to the carb then the egine will stop running because of no fuel.

 

Correct the firt issue then report back. Hopefully it is just a FP that needs to be replaced.

 

Also as Don stated using starter fluid can be dangerous. The Starting fluid has a tendency to wash the oil from the cylinder wals if the car does not fire over.  I would recommend that you get an electric fp have it installed as far back near the gas tank as possible. Then you can always use that to get fuel to the carb.  When a mechnaical FP fails the electric will still push the gas to the carb, Also help when the car has sat for a long time and if you do have a vapor lock issue it then can also push fuel through the system.

 

Rich Hartung

Desoto1939@aol.com

[wdoland]

Will let everyone know what happens with the fuel pump. I read somewhere that I should remove the mechanical fuel pump and block off the hole so that if it fails, gas won't enter the engine. I thought about getting an electric fuel pump but I'm not sure how to wire it up. I still haven't installed my dash clock because I'm not sure how with a 6 volt positive ground system. I'm reading up on it now, but that's another post..

Right now I'll just work on getting "Walter" started.

[greg g]

Now something to check before you install the new fuel pump.  The ones in country now seem to be made or re manufactured  in Mexico.  The "craftsmen" down there seem to have forgotten the need of staking the cam lever fulcrum pin.  This simple procedure locks the pin in place within the casting.  Without this process, the pin tends to walk out with use.  This has led to simple pump failure from lack of leverage to move the diaphragm, to the engine ingesting the cam lever, and spitting it out through the oil pan.  I have personally witnessed both scenarios.

 

So check your "New" unit carefully.  Several folks here have addressed retaining the pin in proper position by fabricating a sheet metal retaining clip that bends over both ends of the pin.  Others have properly staked the pin through the proper application of a prick punch and hammer.

 

Once you have your new pump installed, you can verify fuel flow is proper by doing a simple flow test as outlined in the shop manual.  You may also want to run some low pressure compressed air into the fuel line from the inlet side of the pump to the tank.  This will clear the in tank filter and move any debris in the tank away from the pickup.

 

If the filter you are referring is the glass bowl type attached to the carburetor inlet, you might also want to take it apart and check the fine brass screen these usually have in them.

[wdoland]

Thanks, Greg. The fuel pump says it's made in the good ole' US of A but I'll give it a good check anyway when I get it. I have read about people getting rid of the in tank filter but no one has said how. I read that it looks like a piece of coral after all these years. How do you get to it and is blowing air into the tank enough so you won't have problems down the road?

[Don Coatney]

As Greg said using compressed air from the pump towards the tank is a good idea and this can blow the in-tank filter off the line and this can be a good thing. Suggest you also do a complete inspection of the line from the tank to the pump. Any small pin hole will suck air and not gas. I also suggest you install an in line filter between the tank and the pump.

 

Once again, what are you using for an air filter? Prior to this latest no start issue how did your engine run? How many miles have you driven it?

[wdoland]

Sorry, the air filter is the original oil bath that I soaked in kerosene, dried, and filled with new oil (to the proper level)

Also, I was going to take off the old fuel pump and was thinking about what Greg said about the pin. I see what looks like a pin coming out where one of the bolts to the fuel pump. I took a picture of it now if I can figure out how to post it.

http://imgur.com/ht2pzzp

Edited August 15, 2013 by wdoland

[Don Coatney]

I think you have found your problem. That pin should be centered as it is the pivot point for the actuator. Looks like it slipped out and no longer in a position where it will work. Pictured is the pin in a fuel pump I recently rebuilt. It has circlips holding the pin in place.

 

[wdoland]

Great news! I think. Can I bump the starter to get the pin back in or do I have to take the pump off? What size is that pin for circlip?

 

Oh, Don, did you see the 

Leesburg Air Show - Northern Virginia

post? I saw that you were coming up to Front Royal in Sept.

I'm north of there a few miles.

Wayne

Edited August 16, 2013 by wdoland

[TodFitch]

Great news! I think. Can I bump the starter to get the pin back in or do I have to take the pump off? What size is that pin for circlip?

 

Oh, Don, did you see the 

Leesburg Air Show - Northern Virginia

post? I saw that you were coming up to Front Royal in Sept.

I'm north of there a few miles.

Wayne

Pull the darned thing off: You'll need to get the pin through the actuating arm pivot and its only two bolts and two fuel line connections.

 

I think that your pin will be too short for circlips. . . and not grooved for them anyway. The one Don has is from Antique Auto Parts Cellar and they make good quality repair kits that anticipate things like this. See my above post about getting a repair kit from them.