Boiling Gas???

[srestum]

Okay, major problem. I rebuilt the carburetor about two weeks ago. Everything was fine for about a week. Then I went into a store and came out and the Bronco wouldn't start. From then on, it will not idle at all and I've done my best to read the manuals I have. I pulled the limiter screws out and blew air into them and checked the pcv valve, nothing helped. Then, in a fluke, I opened my hood right after I drove home. I only went about a mile and I live in Montana, where it's not exactly warm right now, and the gas was boiling in the carburetor. The only reason I know is because it was so loud that once I opened the hood you could hear the bubbling before even taking off the air filter. There was also wet gas on both sides of the carburetor. Please help. I don't know enough about this stuff and Mr. Reliable no longer runs reliably. Thanks to all who read. Scott

 

[76Broncofromhell]

Sounds like your carb is in need of a rebuild! A rebuild kit is only about $40 and has everything down to the heat isolator.

 

[srestum]

Sounds like your carb is in need of a rebuild! A rebuild kit is only about $40 and has everything down to the heat isolator.

That's the thing. I just rebuilt it!

 

[72bronco]

If the only thing you did was rebuild the carb then I don't see why you would be suddenly boiling fuel if you weren't before. It must be something else. Your air fuel mixture or your float levels could be set incorrectly. Another possibility is a clogged jet. Perhaps you left some debris in there that worked it's way around. I'd strip it down again, clean it, blow everything out with an air hose, and then try it again.

If that doesn't work then another possibility is that it isn't related to your carb at all. You said it ran fine for two weeks. It could be your coil, distributor, or ignition. I've done that in the past where I assume something is a carb problem but it turns out to be something completely different. Don't assume with a bronco.

 

[72bronco]

Or even your fuel pump. I used to have all kinds of weird problems on my bronco that I assumed was the carb, but when I went to an electric fuel pump they went away.

 

[bert]

If its pushing gas out when you shut it off I would check:
The float level,
The float drop,
Float is not rubbing side of carb,
Float is not too heavy,
Make sure the retainer clip is intalled correctly,
No dirt in the needle and seat,
Seat is not loose.
You said it worked great for two weeks after the rebuild. Its been my experiece to go back and double check the last repair if it seems related to the new problem.
Why did you clean it to begin with?

 

[guest]

carbs

You didn't mention what carb type. Yes, the fuel can easily boil in the float bowls. Especially if the carb spacer/insolator has been removed. In trying to gain hood clearance with aftermarket intakes and air cleaners, the spacer is frequently sacrificed. regarding your rebuild, if the OEM, 2-barrel carb, the float spring and pivot assembly is tricky. Have made the same mistake myself. The rebuild directions that come with the kit are pretty vague about this detail. Oh, have also seen a fuel line so hot that the fuel vapor was pushed past the needle seat. Caused the same results.

 

[Rustytruck]

Not knowing what year truck and carb you are using doesn't help us much. but here goes. Stock 2 barrel carb.
Most likely suspect is low fuel float level. Then if your truck is 72 or newer it probably has an egr valve. this valve is vacuum operated if the lines are not hooked up right the valve will stay open and the truck will run hot and not Idle. The carb needs the thick carb gaskit under the carb and this gaskit should have plastic rings where the carb studs go through the gaskit. this gaskit is about 1/4" thick. Make sure the vacuum lines are properly routed. Vacuum port on driver side front is for the Distributer and the vacuum port under the choke is for egr and air cleaner functions. The large port in the back of the carb is for the PCV valve. Make sure there is no vacuum leaks and extra ports are capped. any vacuum leaks will lean out the carb and Idle will suffer and the engine will run hot.

 

[4x4man514]

hey guys this sounds like a similar problem i have maybe yall can help me too.i have a holley 850 double pumper on a big block and evry time my motor gets around 200 deg. it starts loading up real bad.it never does this at lower temps.which means i practically cant drive it in the summer.Thanks in advance guys<kevin.

 

[srestum]

Thanks guys for the helsp. Sorry for not giving the information on the truck. It's a 68 with the motocraft 2 bbl (I think stock). I took your advise and opened the carburetor last night. It appears from the rebuild instructions that I was suppossed to bend the float tang down to seat the needle? It made more sense in the pictures. Anyway, I did that and it seems to idle now for the time being, but I don't know why it would have run okay to begin with and not now. The float may have been stuck, but by the time I got to it, it didn't look stuck. If it acts up again, I'm going to take the whole thing off and recheck everything. If that doesn't work, I'll start somewhere else I guess. Thanks again. Scott

 

[BoltBuster]

Make sure your float/bowl gasket is not leaking and the screws are tight. You might not hear gas boiling but rather the pressure of the fuel pump leaking by a gasket on the carb. Check this first-

Did you try tapping with a plastic handle of a screw driver on the top of the bowl to see if the float would drop when it wont start?

Do you have an electric fuel pump?

If so take out the float site plug on the side and have some one turn the key on, not the engine!! and see if the float will raise to the level on the bottom of the inspection port and stop. Your going to need a flashlight and flat head screwdriver.

Mechanical pump your going to need to turn it over a couple of times with the coil wire off, then check it.

Something also you can do is look down the carburetor while you throttle it one time or two ('of course with the engine off') and see if both jets squirt into the throat of the carb strong and the same. You may have clogged a jet.

Alot of old manifolds had a heat pan on the bottom side of the manifold right under the carb area to keep the hot oil from heating up the carb(I'm not sure what years or how long).

Also if hot oil is not getting back to the pan because of clogged ports under the manifold section, this can cause things to heat up also. Not sure if this is your problem-

I don't know what motor you have or if its been changed out for another and some engines had an EGR port that traveled under the carb and can cause heat if stuck in the open or dismantled to the open position.

 

[bpassmore]

Don't assume with a bronco.

Aint that the truth.

 

[DirtDonk]

And for any extra info on the stock Ford carbs, try BubbaF250's site here: http://www.spacedaily.com/images/led-blue-device-bg.jpg and click on the bottom link to the Motorcraft carb page. It's got some helpful info. Usually anyway.

Paul

 

[jpoore]

And for any extra info on the stock Ford carbs, try BubbaF250's site here: http://www.spacedaily.com/images/led-blue-device-bg.jpg and click on the bottom link to the Motorcraft carb page. It's got some helpful info. Usually anyway.

Paul

Hmm, are you sure that's the right llink? I just get an jpg of an blue LED.

JP

 

[DirtDonk]

Ooops! You're right jp, I musta zigged when I meant to CtrlC.
Try this: http://home.earthlink.net/~bubbaf250/index.html
Funny thing was, I even used it to view the page to make sure I was doing it right. I just didn't look at the link when I printed it!
Curious, as Mr. Spock would say.

Paul