The Stovebolt Site Forums The Shop Area Engine Shop Carter YF carb getting too much fuel

I've been dealing with this issue awhile now and I'm stumped. It's been rebuilt twice. Once by myself and then again by a pro carb fellow. I've installed an electric fuel pump and a pressure regulator. No matter what I've done the carb dumps fuel into the manifold and all down the outside of the carb at the middle gasket. Engine is a 235 and it's in my 46 half ton. I installed the electric pump just in case the stock mechanical pump was the issue. I've set the Mr. Gasket fuel pressure regulator to 1 and still dumps fuel. I think the regulator is a joke personally. I don't know how it would run on 1 psi. That's where I'm at and I'm frustrated. Any input is appreciated.
Bob

Put a fuel gauge on the fuel line between the regulator and the carburetor.
In the immortal words of HRL, "test, don't guess."
(I'm pretty sure that it is proper to use, "in the immortal words of", if that person is not dead yet. Please correct me if I am wrong.)

The Mr Gasket fuel regulator isn't calibrated to psi. In other words, 1 doesn't mean 1 psi and 5 doesn't mean 5 psi. It's just an arbitrary gauge that raises and lowers your fuel pressure. The output is solely based on the fuel pressure from the fuel pump.

If the pump is putting out 10psi and Mr Gasket is set to "1", you may be reducing the pressure to 6 psi or 2 psi or something else. Who knows?

The 216 is supposed to operate at 2-4psi. 235 might be slightly higher. Measure it and see what you get. If it's working properly, then your carburetor is the culprit.

Need to verify fuel pressure and the others have suggested.

Also, unless you can confirm otherwise which kit you purchased or which or was used by your rebuilder, there’s a fair chance you have the wrong needle/seat.

The one that is commonly supplied in YF kits is from a Ford application and has a too-large orifice diameter.

The YF carb has a real flimsy diaphragm in it. It takes great care when installing it to get it in right. If the materials are not capable of handling ethanol fuel it can damage it. If this dia. leaks it can cause flooding.

George

What electric pump are you running?

Carl, I stole that phrase from the Sun Electric Co. equipment that was in Dad's shop in the early 1950's, so I'm pretty sure it came about before I discovered America!
LOL!
Jerry

I'm running a Carter 6 volt electric in place of the stock mechanical pump on the 235.

OK so I picked up a gauge today, installed it and I get 4 psi. I found at first that no pressure would read. So then I cranked down the screws that hold the top casting to the main body. Then I was able to get a reading of 4 psi. While the pump was on I could see fuel running out of the small nozzle inside the venturi inside the throat of the carb. I think from there it runs to the outside of the carb through the shaft hole on the fuel inlet side of the carb. It's really hard to tell where the fuel is leaking out from on the outside of the carb.

I think your fuel bowl is overflowing because the inlet needle valve isn't seating properly and/or the float is sunken or stuck.

Read through this thread:
https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1411879/2.html
regarding how true the cover that fits over the diaphragm is, as well as the size of the hole in the needle & seat valve. I had similar issues with my 964S YF on a 216, and sourced an original needle & seat set off of eBay and it's running great.

If the fuel delivery system is stock, then the YF used on Chevrolet engines WILL flood if the typical FLAPS fuel valve is used.

If an electric pump has been added, then the addition of a regulator with a bypass is pretty much mandatory.

The typical inline dial type regulators from your FLAPS regulate pressure by restricting volume. If the engine is used in a race vehicle, and using the rated fuel flow capacity of the regulator, the the regulator will work (sort of). If the engine is at idle, changes are good the output pressure from the regulator is IDENTICAL to the inlet pressure.

These regulators are quit useful.......................IF you have a strong right arm, and a rabbit problem in your garden.

Adding a bypass regulator may still not solve a flooding issue if the FLAPS kit fuel valve is used.

The most common valve used in the YF carbs designated for Chevrolet use is part number 25-239s, with an orifice of 0.081 inch. The typical FLAPS valve would be a non-spring-loaded replacement for 25-1076s with a 0.101 inch orifice.

Jon

Thanks Jon, I installed the electric pump simply to rule out a problem with the mechanical pump. This also allows me to pressurize the line and try to see where the fuel is leaking from without starting the engine. So yes it dumps fuel all over once the pump gets going. Also the regulator was an uneducated attempt at an easy fix in my mind. Too much pressure, put in something to lower it...
Should I be replacing the fuel valve again? What part number would I search for to get an original one? The second rebuild was done by my buddies "carb guy" whom he relies on for all of the rigs he restores and works on. It's a reputable place with lots of expensive classics. Also I don't know what the acronym FLAPS stands for.

Before replacing anything, test!

How much pressure is at the carburetor? Gauge!

What is the orifice size of the fuel valve seat? Measure!

Is the fuel valve spring-loaded? Eyeball test!

Too easy to throw money with the only results the lightening of one's wallet.

Test first!

And

(F)riendly (L)ocal (A)uto (P)arts (S)tore

Jon

Um, well thanks Jon. I stated that I HAD to purchase a gauge to TEST the pressure. 4psi. I don't have a pin gauge set to check the valve seat dia. So I'll have to BUY that...
Your input is awesome to have but I feel you are frustrated or terse with me. Sorry, you can't hear tone or inflection on here.
I'll continue to do what I can with what I have and utilizing the info I glean from here.
Bob

Unfortunately Bob unless you have pretty thick skin you are going to have a rough time surviving the plain to the point answers you may get to your questions. Rest assured it’s not you it’s the way several of the site’s experts choose get their points across. Just let it roll off and take the advice offered and move on. BTW you ain’t seen nothing yet!

You probably have drill bits in 32nd or 64th increments. That will suffice for estimating which size orifice you have.

Bob - not frustrated, nor intending to be terse; simply attempting to convey information; sorry you took it the other way.

Pin gauges are wonderful, but a 1~60 drill bit set will get you close enough in this case; most folks have one of these.

SOME of the FLAPS will loan a fuel pressure gauge, but not a common thing.

All of us can guess, but if we guess wrong; and you use our guess as a fix, it costs you money, not us.

The money NOT wasted in guessing will help you acquire test equipment.

Another thought: locally in this area, every podunk town (and I happily live in one) has a cruise-in every 4~6 weeks during the summer. If you have them in your area, attend, make a friend. Sometimes a friend with tools and knowledge, AND a supply of your favorite beverage can be a much more enjoyable Saturday than the TV schedule.

And 4 psi is marginal to too much with the correct fuel valve, way too much for the wrong one.

Stay with it, you will get it fixed.

EDIT: JW - you type faster than I

Jon

“Friendly Local Auto Parts Store”.

I’ll keep trying to sort this out. I have and maintain three other classics but this one has me stumped. I just want to set it back on the road. I’m usually at most of the show n shines.

Now that made me laugh out loud right there.

Just an update;
Finally located the proper fuel valve and needle. Put it
It all back together and fired it up. Same problem᠁
Sooooo I decided to go drastic. Popped the top, grabbed the float with a couple pairs of needle nose pliers and gave it a bend. Put it together and it ran. No leaking. But then it starved. We’re close! Another couple round’s going back and forth and I got it close. So close.
It’s way off of the stated float level the rebuild kit said to adjust to. Maybe it’s not the correct float? Who knows. I’m closer than ever now and much happier.

Where did the kit come from? Do you know if the carburetor is even the correct YF for a Chevy truck.

NAPA sold the kit. Turns out the carb was jetted for a ford 300. So I did find the proper jet. Just don’t know the spec for the float level for this carb on a Chevy motor.

If the float level is too high, gas will dribble out of the venturi when the engine is idling. Set the float as high as possible without gasoline dripping into the airflow at idle speed. If you could see a cross section of most carbs, the level of the liquid in the float chamber will be just slightly below the narrowest point in the carburetor body (the venturi) so just a slight increase in airflow above idle starts drawing fuel into the air stream. The higher the float level is, the richer the carb will run at any midrange to cruise RPM.
Jerry

What is the carb number? I may have a spec sheet for it I can scan.

I have searched the carb over and no numbers. Just says Carter YF made in USA

Post a pic of the carb, Bob. Might be able to help you locate numbers if I can see what you’re working with.

Bob, take a close look in the area I've highlighted in the attached pic. That's where the model number on a YF will be. It may take some cleaning to find the numbers.

Another location as well on mine

I'll take another look. My carb is clean as a whistle. Boy those numbers are stamped very nice and clear on you two fellows carbs. Mine has been looked over with a magnifying glass. Frustrating. Can't really get any proper data for the float levels without a model number... I've been tinkering with it the last couple days. I have it close but it still starves out going up a bit of a grade.

Bob, the Carter YF that came with my truck didn't have any numbers , either.

It was determined by carbking to be a mongrel re-man carb from the 70s or 80s or something. Base was from a 50s Willys Overland Jeep and the body was from from some 60s Jeep. It was jetted wrong, etc.

I ended up getting a correct YF carb for the 216 and rebuilding it with a correct kit.

I'll bet yours is a re-man assembled from random hodge podge parts and sold as an off-the-shelf Fitzall that offers mediocre performance to a variety of vehicles instead of perfect performance for your specific application.

Bob if there is any way to post an image of your carburetor, some of us might be able to help with identifying or at least we might see some clues. For what it may or may not be worth, I have used an electric fuel pump since 1996 and I've learned about 2.5psi to 3psi pressure is ideal for the 235.

One thing which could be important here: unless I missed it I'm not certain which year of 235 you have. There were several versions of the YF made for 235s. They all recognized differences in design for the engine. And there were numerous YF models made for many other makes of vehicles, too. We're happy to help.

Oh it’s very likely a Frankenstein carb. It came with the truck when I bought it earlier this year, in a box of parts. The carb on the truck was a Chinese knockoff. That. Can’t. Happen.
Here’s a couple images

It MAY be a genuine Carter since it says “Made in USA” on it. But that may be counterfeit.
It has the patent number list on the side but they seem pretty worn (or sandblasted) off. Maybe that’s what happened to the model number as well.

Thanks Bob. Man oh man. I was hoping to find some hint but as you said there's virtually no clue, is there? I can read the numbers on the throttle body but those are generally of no use...other than they may indicate when it was made. Maybe. You probably are on the right path by altering the float level...monotonous as that work will be. Generally 1/16" difference in float height will amount to 1 step difference in the jet. My experience has been even a very slight change will make a difference. Maybe raising the float level a wee bit would help with the lack of power on incline. Just be certain you don't change it enough to cause it to dribble into the venturi, though. At a point it will start doing that. Sorry...had hoped to have some more information for you.

For clarification purposes, I don't know what I am talking about, but every carburetor I have ever worked on, once I set the float level as per the instructions, the flat part of the float (closest to the carburetor body) was parallel with the carburetor body when held upside down so that the needle was seated in the seat. I suggest that you start there and give it a go. I can't help you with the float drop setting. My seat-of-the-pants technology has it's limitations.

Just for giggles, try measuring the center to center spacing of the two mounting bolts (to the intake). Also check to see if the mounting holes in the throttle body have been slotted.

One of us is going to be surprised with your answer.

Jon

You did post that you had acquired the correct fuel valve.

So, GUESSING that I am right:

Invert the bowl cover and allow the float tab to rest on the pin inside the spring of the plunger (DO NOT PRESS ON THE FLOAT).

Measure 9/32 inch from the free end of the float to the surface of the bowl cover without the gasket. Adjust by bending the tab a.k.a. lip of the float. If it floods, try 5/16 instead of 9/32.

While you have the bowl cover off, read the number on the metering rod just below the pigtail.

And after all that, it will probably be me that is surprised!

Jon

I had to make a trip to Wyoming for a couple weeks. I’ll use your suggestions when I return.