Vapor lock or Faulty fuel pump?

[jgf100]

Hi, i was heading back home and truck stopped on me, fortunately a few houses down from mine. I notice the fuel filter was near empty, so that worried me since I just filled up a couple days ago. I had my son crank it over and i noticed fuel was not being pumped in. I put some gas directly in carb, cranked it and filter got full and truck turned on. Then 1 min later truck turned off. I noticed that fuel from filter went down to almost empty after a couple minutes. I figured bad pump, but after a few hours I tried again and fuel did go into filter and turned on, but it idled terribly. Turned it off and it wouldn't turn on again. I doubt that's it's vapor lock since it was cool. Fuel pump issue? Carb issues? Anything else that i can check?

[basketcase0302]

jgf100
Hi, i was heading back home and truck stopped on me, fortunately a few houses down from mine. I notice the fuel filter was near empty, so that worried me since I just filled up a couple days ago. I had my son crank it over and i noticed fuel was not being pumped in. I put some gas directly in carb, cranked it and filter got full and truck turned on. Then 1 min later truck turned off. I noticed that fuel from filter went down to almost empty after a couple minutes. I figured bad pump, but after a few hours I tried again and fuel did go into filter and turned on, but it idled terribly. Turned it off and it wouldn't turn on again. I doubt that's it's vapor lock since it was cool. Fuel pump issue? Carb issues? Anything else that i can check?

The fuel filter says a lot, (prob the pump) but I'd still try to get it cranked again with a pressure gauge in line to see what the pump is pushing out. There's also a few things behind the pump you should look at AND TRASH/RUST IN THE TANK WOULD BE THE FIRST THING I'D START AT THERE.

Have you ever replaced the tank/have you ever had the sending unit out (there's less than 1/4" from the bottom of the sending unit pickup and the bottom of the tank so real...easy for anything to clog it there).

Not ruling out carb but I'd focus on the fuel supply to start with and confirm these things first.

[jgf100]

jgf100
Hi, i was heading back home and truck stopped on me, fortunately a few houses down from mine. I notice the fuel filter was near empty, so that worried me since I just filled up a couple days ago. I had my son crank it over and i noticed fuel was not being pumped in. I put some gas directly in carb, cranked it and filter got full and truck turned on. Then 1 min later truck turned off. I noticed that fuel from filter went down to almost empty after a couple minutes. I figured bad pump, but after a few hours I tried again and fuel did go into filter and turned on, but it idled terribly. Turned it off and it wouldn't turn on again. I doubt that's it's vapor lock since it was cool. Fuel pump issue? Carb issues? Anything else that i can check?

The fuel filter says a lot, (prob the pump) but I'd still try to get it cranked again with a pressure gauge in line to see what the pump is pushing out. There's also a few things behind the pump you should look at AND TRASH/RUST IN THE TANK WOULD BE THE FIRST THING I'D START AT THERE.

Have you ever replaced the tank/have you ever had the sending unit out (there's less than 1/4" from the bottom of the sending unit pickup and the bottom of the tank so real...easy for anything to clog it there).

Not ruling out carb but I'd focus on the fuel supply to start with and confirm these things first.

HI, I just installed engine after having it rebuilt, so the tank did sit for about 4 months. It had very little fuel so, I topped it off with fresh gas and seafoam, probably not a good idea. It was running real nice for about a week until yesterday so I thought I was in the clear.
Another think I noticed that I forgot to mention was that after cranking engine, what looked like steam, came out carb? Something I need to look out for? Thanks for help.

[jgf100]

UPdate: I decided to check spark plugs before anything and after removing the first cylinder plug, a TON of fuel came out. Same thing with cylinder 5. Not good obviously. I removed the line from carb after the filter and gas kept pouring out. I always assumed that no gas would flow if the engine isnt running, which in turn the fuel pump wouldn't be 'pumping'. What am i dealing with here? Its obvious gas keeps pouring into engine, but is that the fuel pump or carb's problem? What else could this have affected? Neighbor of mine told me that there could be gas in oil now? Really frustrating since I just paid a good amount to have engine rebuild. Any help is appreciated.

[basketcase0302]

=jgf100
UPdate: I decided to check spark plugs before anything and after removing the first cylinder plug, a TON of fuel came out. Same thing with cylinder 5. Not good obviously. I removed the line from carb after the filter and gas kept pouring out. I always assumed that no gas would flow if the engine isnt running, which in turn the fuel pump wouldn't be 'pumping'. What am i dealing with here? Its obvious gas keeps pouring into engine, but is that the fuel pump or carb's problem? What else could this have affected? Neighbor of mine told me that there could be gas in oil now? Really frustrating since I just paid a good amount to have engine rebuild. Any help is appreciated.

Only one thing will let gas flow through the carb when the throttle is not pushed-the needle and float assembly.
If it's a Holly that doesn't surprise me at all as the secondaries on them are known for doing this-I ALMOST BLEW AN ENGINE 30 MILES OUT IN THE WOODS ON MY SWAMP BUGGY ONCE SOLD ALL MY HOLLY'S AFTER THAT!

Even if it's not a Holley your needle and float assembly are stuck/not seating, (could just be as simple as the spring not seating the needle valve in the carb that lets get flow through the carb/could be trash has the needle off its "seat"). If your not good with carbs, (rebuilding them can bring on more problems it you're not careful-I'd locally source a rebuilt carb to put on it.

[basketcase0302]

And yes I'd almost be willing to bet the trash from the tank got past the fuel filter to cause the needle and seat to not stop the gas flow through the carb.
GET ANOTHER REAL GOOD FUEL FILTER BEFORE CHANGING THE CARB OR YOU'LL CONTINUE TO HAVE MORE ISSUES! IS YOUR FUEL FILTER THE STOCK CANNISTER TYPE ON THE FUEL PUMP ITSELF OR AN AFTERMARKET? NOT HIGHLY RECCOMMENDED BUT IN YOUR CASE PUT A 2ND FILTER INLINE TILL YOU CAN GET THE GAS TANK PULLED OUT AND FLUSHED!

[jgf100]

And yes I'd almost be willing to bet the trash from the tank got past the fuel filter to cause the needle and seat to not stop the gas flow through the carb.
GET ANOTHER REAL GOOD FUEL FILTER BEFORE CHANGING THE CARB OR YOU'LL CONTINUE TO HAVE MORE ISSUES! IS YOUR FUEL FILTER THE STOCK CANNISTER TYPE ON THE FUEL PUMP ITSELF OR AN AFTERMARKET? NOT HIGHLY RECCOMMENDED BUT IN YOUR CASE PUT A 2ND FILTER INLINE TILL YOU CAN GET THE GAS TANK PULLED OUT AND FLUSHED!

The fuel pump has the stock canister type filter on it. I then have a plastic filter in line before the carb. I plan on taking off the carb today and taking to shop. Also got a new fuel pump just in case. I did notice the gasket on pump to block was broke. Don't know if that causes some vacuum issues. Thanks for info. Hope to have an update soon.

[jzjames]

IMO, NOT the fuel pump, not rust from the tank. Get your carb straightened out.
Gas pouring into the cylinders isnt good, and yes, I would change the oil after the carb problem is solved.

Why dont you take the plugs out and crank the starter a bit - with the gas line disconnected - to dry out your cylinders. That might spray out any gas youve got in the cylinders. You might squirt some oil in them as well for good measure.

This is what I’d do, but take with a grain of salt - I’m no great mechanic.

[basketcase0302]

good advice from jzjames, especially about yanking the plugs, (pull the coil wire + and insulate so no spark so the engine doesn't try to start-I crank the engine over with a remote starter switch like this) cranking it over to dry out the engine. And leave the plugs out a day if there were still alot of fuel in the cylinders. Really no need to change the oil unless it smells like the gas got past the rings into the crankcase, (if so, yes def change the oil).
And yes, that rubber O-ring causes more guys issues than I can count here! I hated the FE CANNISTER FUEL PUMP as the ethanol fuel attacks that rubber O-ring the very first time that type of fuel is put in the tank, (as well as the carb moving sealing rubber parts IE:needle valve which are still made of soft butyl type rubber construction if I'm not mistaken). Ethanol fuel will also cause issues with the rubber o-ring gasket at the gas tank sending unit and a few other places so look carefull at the fuel you're running after all is said and done.

One resource we have is a site called:
https://www.pure-gas.org/

[Ohiotinkerer]

good advice from jzjames, especially about yanking the plugs, (pull the coil wire + and insulate so no spark so the engine doesn't try to start-I crank the engine over with a remote starter switch like this) cranking it over to dry out the engine. And leave the plugs out a day if there were still alot of fuel in the cylinders. Really no need to change the oil unless it smells like the gas got past the rings into the crankcase, (if so, yes def change the oil).
And yes, that rubber O-ring causes more guys issues than I can count here! I hated the FE CANNISTER FUEL PUMP as the ethanol fuel attacks that rubber O-ring the very first time that type of fuel is put in the tank, (as well as the carb moving sealing rubber parts IE:needle valve which are still made of soft butyl type rubber construction if I'm not mistaken). Ethanol fuel will also cause issues with the rubber o-ring gasket at the gas tank sending unit and a few other places so look carefull at the fuel you're running after all is said and done.

One resource we have is a site called:
https://www.pure-gas.org/

Thanks for that link - my local Bellstores has what they call 90 REC that is ethanol free but I take the bump to Tennessee ever once in a while so this info is nice to have. I can attest to the problems that normal gas can cause after forgetting to flush out the system once when i had to use normal pump gas - after sitting over winter here in Ohio I had to tear down and clean the carb because it was so garbaged up l had to drive it home from the next town with the choke partway on - lesson learned.

[basketcase0302]

Being an airboater...
So I sold my $50K counter rotator airboat back in 2008 once ethanol free gas hit $5.00 a gallon!
Now...AVGAS (100 LL) is actually cheaper down here than ethanol free gas!

Thought I'd never see the day!!!

[jgf100]

IMO, NOT the fuel pump, not rust from the tank. Get your carb straightened out.
Gas pouring into the cylinders isnt good, and yes, I would change the oil after the carb problem is solved.

Why dont you take the plugs out and crank the starter a bit - with the gas line disconnected - to dry out your cylinders. That might spray out any gas youve got in the cylinders. You might squirt some oil in them as well for good measure.

This is what I’d do, but take with a grain of salt - I’m no great mechanic.

Thanks for info. After reading your advice I took carb to carb shop and mechanic said he replaced the needles and that the pump was a little stiff. Other than that carb looked good inside, no rust or junk. I explained to him my problem and he suggested fuel pressure might be too high. He did not seem convinced that the problem was the carb. I plan to check the fuel pressure this week.
1. Could it be fuel pressure ?
2.What is the ideal fuel pressure?

[fastEdsel]

Do you have a vented fuel cap on your fuel tank?

[jgf100]

Do you have a vented fuel cap on your fuel tank?

Not sure. I have not changed it since I bought it, but if the fuel is flowing out the tank out the fuel line, doesn't that mean that it is venting?

[fastEdsel]

I have vented fuel caps on all my Ford's. When the fuel is being sucked out of the tank, the volume removed has to be replaced by atmospheric air. A vented fuel cap will do just that or you will be chasing the small problems for nothing. If your cap is stamped "vented" or "not vented remove slowly" then replace it anyway, they're only new once. If your truck quits again then quickly, in a safe way, remove the cap and listen for a vacuum sound. Vented caps are fairly inexpensive and will save you a lot of grief in the long and short term. Our airplanes also have vented fuel systems for obvious reasons. Hope this helps, keep in touch.