Technical Carter YF flooding issue, need guidance

I've been at this for weeks and I'm getting desperate.

Car is a '54 Nash Rambler, I have a build thread going on it here

https://jalopyjournal.com/forum/threads/1954-nash-rambler-light-re-commissioning.1337941/

(I'd post a nice pic, but the board won't let me post certain pictures, seemingly at random)

The carb in question is the original Carter YF, with tag number 2014S. Seems like virtually the same carb that a ton of Jeeps used in the 50's and 60's along with a ton of other vehicles, it's not some oddball Nash-only thing.




I had the car running and idling using a little lawnmower style tank, gravity feeding into it, so I cleaned out the original tank (turned out nice), blew out the gas lines, added 2 inline filters, rebuilt the original mechanical fuel pump, and rebuilt the carb. The carb was full of fine rust particles from the tank when I first took it apart, but it cleaned up really nice, and the car only has 37K miles on it so nothing seems like it should be worn out.

Now I have a horrible flooding issue, as soon as I try to start it, gas comes out the bottom of the carb, maybe around the throttle shaft or at least in that area, hard to tell the exact source.

I've had the carb apart several times, checking and rechecking things, and I can't figure it out. The float is not sinking and the needle and seat seem to be sealing up nice. Last time I took it off, the bowl was still full of gas, and I could not blow into the fuel line to get air past the needle, even as hard as I could blow, so the float isn't sinking, and when I took it apart immediately afterward, there was no fuel in the float. The float does not seem to be hanging up on the pin either, and it's adjusted to factory spec.

The needle and seat seem to seal up nice, with the carb top off I can blow through it fine and then if I tip it upside down so just the weight of the float is holding it closed, I can't blow through it. It was clean every time I checked it, and I tried using the original needle and seat (all metal style) and the Viton tipped one, and neither made a difference. Currently have the Viton one back in.

I blew through every passageway and found none to be blocked, I figured maybe the fuel pump was making too much pressure after being rebuilt.

I've had 3 different pressure regulators on this car and they all seem like garbage. This dial one was the only one I could get to work at all, I had it set at 2 psi on it's dial and my inline gauge read 3 1/2, but one time I did get it to run long enough to at least check the gauge under hood and see what the pressure was.




I'm using what I believe to be a quality pressure gauge.

Knowing that those adjustable dial regulators are kinda shitty/unreliable, I tried a generic Holley look-alike one off of eBay and it was trash, couldn't get it to stop leaking and it wouldn't hold back any pressure, I sent it back.

Reading some reviews online, one of the best reviewed regulator was this Spectre one, so I bought one of those. Doesn't leak, but is supposed to be adjustable from 1 to 4 PSI, and even at the lightest spring tension it still seems to make 3 psi, and it's not stopping the fuel flooding issue.



Seems odd to me that a rebuilt stock/OEM mechanical fuel pump would make so much pressure it would blow fuel out of the carb almost immediately, to the point the car barely starts, won't idle, and leaks quite a bit of fuel out the bottom of the carb. I feel like I shouldn't even need a regulator.

What am I missing here? I must be doing something wrong. I do notice the throttle shaft does feel like it's worn/has some play in it, although I would think that would just cause a vacuum leak and not flooding, correct?

I need to know what else would cause these issues, what to check, and also if there are any fuel pressure regulators for very low pressure applications that aren't complete garbage.

 

Is the fuel tank vented properly? May be building pressure at higher temperatures. There's bound to be some form of pressure regulation built into the pump. Might have misplaced a spring or valve during your rebuild? Maybe a pump inlet valve not sealing properly.

 

A dumb question as you said you went through the carb, cleaned etc. did you set the float level to spec?
Dan

 

I'm going to check on the tank vent, I think it just uses a vented cap. This happens immediately though, like it won't even start and run properly before it starts pushing fuel out. Like a couple cranks, I can get it to start but running very poorly, and immediately is flooding and leaking out the bottom. Seems like that wouldn't be a tank venting issue, but I'll look.

As for the pump, I can't tell how much pressure it's making since I can't get it to run long enough to even get under the hood and look at the gauge. But even if the pump was making a ton of pressure, shouldn't the regulator resolve that issue? The pump "rebuild" was really just diaphragms on both ends (it's a dual action one with a vacuum pump) and cleaning everything nicely, the little one-way check valves in the pump seemed to work very nice (held pressure one way, released the other way) so I didn't replace them, the original ones looked to be much better quality than the stuff that came with the kit. I'm pretty confident nothing is missing, I don't know how a cleaning and new diaphragms would suddenly double the fuel pressure, but maybe? I honestly don't know.

Yes, float set to spec, as per the Nash manual, 1/2" from the top without a gasket. I cut a little "feeler gauge" at a half inch out of an old gift card so I could slide it under and get an exact measurement, instead of just eyeballing it with the little measuring stick they give you. I feel like it's dead-on, but even if it was off a tiny bit, I can't see it being the cause of this issue.

 

Did you replace any springs in the fuel pump rebuild? At work we got a notice from one of our vendors about rebuilt fuel pumps and kits. It said a lot of them now have the wrong pressure springs in the rebuilt pumps and in the kits. So if you used the new spring in the kit, the pump may now be putting out way more pressure than it was originally. If you did change the spring, and have the original one, put it back in. It may fix your problem.

 

I don't think so, but I do have the old parts/leftovers from the kit yet, so I'll check and see if there even was a main pressure spring in there, and if so, which one I used.

Again though, seems like with a pressure regulator on it, the carb shouldn't immediately be blasting fuel out the way it does, even if the pump is putting out way too much pressure.

 

OK I've got new info that may be helpful (or in my case, even more confusing).

First I tried to start it with the gas cap off, just to make sure it wasn't a vent issue, and that did not resolve it.

Then I figured I'd hook up my little gravity feed tank again, and send the fuel from the pump directly to a gas can, with the gauge but without the regulator.

I wanted to see if the engine would run OK with just gravity feed fuel, and also if I could get it to idle, I could figure out how much pressure the pump is making.

I hooked that all up, and even with the fuel pump totally out of the picture, and with only gravity feeding fuel to the carb, it's spitting fuel right out of the top of the carb, all over the place.

So we've taken the pump and tank totally out of it now. What would cause fuel to spit out the top of the carb? Maybe this isn't even a carb issue? The more I dig into this, the more confused I'm getting.

 

I just checked my firing order and that seems right, I never moved the distributor or anything so I don't know how or why it would suddenly be way out of timing, I'm so confused.

 

By far the most common cause of flooding in a non-Ford Carter YF has nothing to do with adjustments; rather, the use of incorrect parts.

A vast majority of the YF's used were used by Ford, often for the 300 CID engine.

Many of the cheaper FLAPS kits use the Ford valve for all YF applications (it costs money to produce low-volume parts).

The orifice in the fuel valve seat for the Ford YF is 0.101 inch.

The orifice in the fuel valve seat for the Nash is 0.080 inch

Doing part of the math:

Area = pi times r times r

So Nash fuel valve area is pi times 0.040 times 0.040 = 0.0050 square inches

The Ford fuel valve area is pi times 0.0505 times 0.0505 = 0.00801 square inches

The area of the Ford valve is 60 percent larger.

I am too lazy to finish the math as to how this effects the pressure that the float must exert to close the larger valve, but even setting the float too low may still allow flooding as the pressure will bleed through.

We run into this issue frequently with the Jeep YF and the aftermarket Chevy YF.

The part number for the original valve used in the Nash is 25-195s.

Check the orifices in your fuel valves.

Jon

 

Using a gravity feed system and still over filling the carb bowl tells me something is way off. If the gas tank is two feet above the carb the pressure would be 0.64 psi I don’t believe that is any where near enough pressure to lift the seat.
Is the gasket #27 in place?, also when setting the float level did you have the top #23 upside down, the float level needs to be set with the top upside down.
From @carbking
https://www.thecarburetorshop.com/Service_Carter_YF.pdf

Dan

 

If the float is brass and has a fuel in it, drill a small hole less than 1/16" in it, opposite of where it is leaking. Shake it to get all the fuel out, then a heat gun helps to dry it out. Shine up the brass with fine sandpaper and solder the original hole and the one you drilled. I have fixed lots of them this way.

 

I appreciate all the replies. I am 100% confident that the float is not sinking, and I'm also confident it's adjusted properly. I really don't think that's the issue. The needle and seat seem to be opening and closing fine, I also can't see how that could possibly be the issue.

The openings in the needle seat looks identical to the original one. I still have the original one and I tried it as well and it seems like there's no difference made between the old needle/seat set and the new one (other than a small float adjustment between the two)

I do wonder about the metering rod and metering rod jet. It seems like the jet is huge compared to the diameter of the rod, like the position of the rod wouldn't even matter up or down, there's always a ton of space for fuel to go through. Would this cause issues? I didn't replace either of these, I just cleaned them and re-installed them, but that doesn't mean they were right when I took the carb apart, who knows who's been in here.

The rod says 75-779 and the jet just says 120 on it, as best as I can read.








Also, does this seem like it's assembled right? The tip of the rod isn't even in the jet, it's kinda off to the side until you move the throttle, then it slips back down, and there's a big gap on the accelerator pump shaft between the #25 piece and #26 piece in the illustration above.

 

I can't really get it started, or just barely, and there was fuel mist puffing out of the carb opening when I did have it running, but it was barely running, and very poor. Like the timing is suddenly massively off (although I can't imagine how, I didn't change it). And even if the timing was off, would that make it spray fuel out of the top of the carb?

Nothing seems to leak or have any issues when the car is just off. The carb will hold fuel in the float bowl fine. But when I try to run it, it runs very poorly if I can get it to start at all, and there's fuel everywhere, including all over the base of the carb, and I can see it blowing out of the top, too.

Maybe I need to take a video of this to better explain what's happening. I can't seem to get it running enough to get out of the car and look at what's happening, to check the fuel pressure gauge or anything like that.

 

Did you get a measurement on #28 orifice .101 for Ford .080 for Nash, like Jon said that could be the problem.
Unless I’m not understanding something the fuel can only overflow the bowl through the float needle assembly. Either the float is sinking or mis adjusted, the seat is defective or of wrong size, or the system is bypassed due to leak - bad gasket, cracked assembly, there is no other path.
Dan

 

You guys respond and type faster than me please disregard my previous post.
Dan

 

Had a friend with a similar problem. 55 Nash and Carter side drafts. the fuel was overcoming the needle and he ended up using a needle and seat from an edelbrock carb and it fixed it for him.something to think about perhaps

 

Last time it did look like a mist, like air and fuel were moving out the top of the carb. I do wonder about a bad valve or something, although I did have it running last year off of the little lawnmower tank with gravity feed, I just can't figure out why I can't seem to replicate that anymore. Seems odd that the valve would suddenly now be stuck or burnt after just sitting in my shop for a year.

It's kinda late tonight and I'm overly frustrated with it so I'm going to call it quits for tonight, but next week I'll try again and I'll see if I can get a video of what it's doing, I feel like I'm not explaining it very well.

 

It's so hard to say where exactly the fuel is coming out of because the car won't stay running long enough for me to get out and look at it. It's bizarre. But I'm a bodyman pretending to be a mechanic and trying to learn this stuff as I go, it might be something stupid and simple and I just don't get it.

I'll circle back soon with more info and hopefully a video showing what's up, maybe Monday. I really do appreciate all of the responses, it's been a frustrating day.

 

I can check compression too.

One last thing, there's no separate intake on this engine, the carb bolts to the head, and when I took the carb off this last time I stuck one of those blue shop towels in the hole just to keep dirt or whatever from getting in there. I noticed that the towel had absorbed fuel from inside and when I stuck my finger in there it's still wet. I wonder if I didn't flood the engine out so badly that it just wouldn't start properly right away when I hooked up the little lawnmower tank?

I might try the little tank again once it's had time to air out/evaporate.

 

Metering rod and jet are correct.

Check the adjustment

And 10-4 on the compression test !

Jon

 

That's good to know about the metering rod and jet. I will dig into this further and Ill report back with what I find.

 

I got it running good again! Here's what I did.

I talked to a friend of mine that does a lot of Pontiac Tri-Power stuff and told him what was going on, he gave me some good advice. He said to try setting the float way below the book-spec, as he has run into several issues of fuel running out of the throttle shafts from too high of a float. He also said I should start by trying to get it running off of the lawnmower tank first, and also that my plugs were probably so cold-fouled that it wasn't going to start anyway until I had those cleaned off.

So I started with the plugs. They were very fouled, a few were wet, and a few were loose!? Kinda unexpected. I could see the plugs were new looking but I never thought to check them for tightness, a couple of them were even wet past the threads a bit. Cleaned every plug, blew out every cylinder to make sure there was no fuel left in there, and put them back together.

Then I set the float way below the factory spec. Factory spec is 1/2" below the underside of the carb top (held upside down) which I re-checked before I moved it and it was right on. Now it's way lower than that, probably another 1/4" down. Might be overkill but I can always tweak that.

And I hooked up my lawnmower tank, and ran my fuel pump into a gas can, with the pressure gauge inline to try to see how much PSI my pump was making.

First attempt at starting, it started up, running a bit shitty at first, but clearing up once it ran for a bit, and no carb leaks/wet carb base. A first success! No internal engine issues found.

It finally ran good enough to idle so I could get out of the car and check the pressure gauge, which read 0. Me not thinking, it won't build up any pressure without being hooked up to the carb, it's just free-pumping into the can. So no telling yet what pressure the fuel pump is making, but at least the engine is good.

So next, I decided to disconnect the lawnmower can and run the engine off of the fuel pump, no regulator but through the gauge to see how much PSI my pump was making.

I set that up, got it running, and it ran pretty good for about a minute, long enough for me to get out of the car and check the gauge which read 9 PSI! Way more than I would have expected. And then it stalled out, with fuel running out of the throttle shaft/soaking the carb base again. But that's clearly too much fuel pressure.

So now, knowing that my pump makes a lot of pressure, I put in my new Spectre regulator (not the old Mr Gasket dial ones, which I know are unreliable), which I had tried to set very low ahead of time but I could never get the car to run long enough to actually read the gauge.

Started it up again and it started at about 4 PSI and with a carb drip but once it ran a bit the drip stopped and the gauge fell down to about 1 1/2 PSI, which the engine seemed to love and no more carb drips. It's probably never run better than it did this last time.

I can probably bring my float level back up from where it currently is, and I could probably also add in a bit more fuel pressure, although this carb seems to like 1.5 and the current float level so I don't know if either of those are even necessary. Maybe once it's out on the road but for now, moving it around the shop and parking lot, it seems to be happy.

Apparently the fouled out (and also loose) spark plugs were what was making it run so poorly, which was (mostly) caused by way too much fuel making it past the carb, due in part to super high fuel pressure from the mechanical pump and also (maybe) too high of a factory float setting.

I really appreciate all the responses and I was excited to share my findings, not the most interesting story but maybe it'll help someone like me in the future figure out what they're doing wrong. Now I'm off to go change out the most horrible oil imaginable.

 

Sweet!