Hey folks, I know this has been discussed numerous times on past forum threads, but I don't remember one aspect of this discussion.

Quick update on my 1924 coupe fuel issue. Fuel starvation begins at 2/3 to 1/2 full tank. Even on slight inclines. I want to pull apart the carb and look for any blockage or sticking floats, but assuming it's all clear I then have two options, go from 1/4" line to 5/16" to see if that helps flow pressure, (I've read that forum thoroughly so I'm not looking to start any controversy with that. Or, I put in a low pressure fuel pump.

Here is the main question that I don't remember seeing...did anyone put on a fuel regulator for a low psi 6v pump? Is that needed with a 2-4 psi pump and did you put a small fuse with the set up? I just want to be safe as I'm surrounded with hills in Lancaster County Pa.

Is the gas cap vent hole open? If the tank isn't vented enough your fuel won't flow. Pretty common in old cars, tractors without a fuel pump.
What about the sediment bowl under the tank. Is the screen partially blocked. Simple things to check for before adding some sort of pump which most don't use in a T.

New fuel tank, sediment bulb, fuel line, and a good quality carburetor rebuild will definitely fix your issue. $400 worth of stuff, but its a sure thing, not a gamble.

If you are running out of fuel to the carb on a slight incline with that much fuel in the tank, bottom line is you have blockage someplace. Even with the tank under my seat, I don't have flow issues till the tank gets down to about the last inch or so. Do not assume that things are clear till you check them.
RE fuel pump, you can buy 6 volt pumps that are low pressure. Buy one of the new type ones (most are very quite), not one of the older type.

Millions of Model T's have operated without a pump and without fuel starvation. Like some other "upgrades", a fuel pump is a band aid sometimes applied instead of fixing what's wrong. These "fixes" often introduce problems of their own.

Fuel starvation DOES happen in a normal stock Model T if the supply gets too low. The saying is that two gallons of fuel is plenty and one gallon is not enough. Your having it with five gallons or more says that something needs fixing, and that can be anywhere from the cap to the carb.

If your car has an aftermarket fuel line filter you may want to remove it sometimes they cause unnecessary headaches.

Hi Scott,

Like you, I have a '24 coupe. The fuel system is entirely stock, 1/4" fuel line, Ford's sediment bulb, even use felt in the pack nuts. I have never had fuel delivery issues.

I live in hilly New Hampshire and even with a low fuel level (1/4 tank) I do not encounter a problem. Methinks that your stock 1/4" line is adequate and the cause of your problem lies elsewhere.

Good luck with your project and please let us know what you uncover. Bill

Okay, great input. The tank is brand new, I did peer into it and it was flawless, no signs of rust or corrosion. Perhaps i have some of that dreaded ethanol slim in the sediment bowl. It appears to have the bung style cap and I never recalled seeing a vent hole in the bung style cap. It doesn't have an aftermarket filter. I didn't check the sediment bowl. Will do that for sure. Thanks guys!

Scott, I went through fuel issues too and read the forum alot. I personally chose to go to 5/16" line.

But my issues were cured when I did the following, make sure the gas cap vent was clear, remove the filter I had placed inline, and make sure the fuel line was sloped upwards at the carb (it went up but then slightly back downward to the carb creating an air pocket).

I don't have answers for your fuel pump questions, and do understand your concerns, but honestly if you can find the issue with you stock setup, you might not need those other parts.

Let it die and immediately open the gas cap. Did you hear air rush in?

i did not try that, I'll try tonight. That would indicate that air is being sucked through the system and isn't air locked....am I interpreting you correctly?

I recently ran into endless fuel starvation headaches with a Center Door. I discovered that the tank was chock full of sediment/rust/debris. I ended up cleaning/restoring the tank. The sediment in the tank was choking the sediment bulb and fuel line. So, consider checking the tank to make sure it is clean. Then make sure the sediment bulb and screen are not clogged.

I had a very frustrating problem with a motorcycle. The tank was above the engine. I had added a fuel filter to catch some sand left from a pain process. At any fuel level, including full, the fuel would not flow into the carburetor even though the bottom of the tank was 4-5 inches about the carburetor! I resorted to disconnecting the vent line and when the engine would start to sputter I would blow in the vent pressurizing the tank. I did this sometimes every 5 or 10 miles or I might go 20 or 30 miles. The fix? I removed the filter and routed the line back to it's factory location. No more problems. NONE! Why that gas wouldn't move to the carb I don't know. All I can say to you is there are probably 1,000's of Model T's out there using the factory fuel pipes and routing that have no problem.

If you must go to a pump, Briggs and Stratton has one operated on vacuum pulses for about $15. I would guess that would be a quick and safe way to use something other than gravity to move the fuel.

Good Luck!

If you have a paper element filter, any water in the fuel will cause you to stall, you don't have one so the vent seems like a good starting point. loosen the cap and drive it and see if that takes care of it.

Rick

If you look at your gas cap it should have a small hole in the top like the one in the picture. Make sure it is not plugged up.

looks like I have a plan thanks to all of you. Thanks for the many years of insight!

Scott,

No, the other way around. If it dies and you immediately remove the gas cap and hear air, it is an indicator that the vent is plugged (Or was never there to start with. I've seen it.). What is happening in that case, is that as you use fuel, no air can get into the tank to take it's place. You eventually end up creating such a vacuum that the fuel can no longer flow down to the carb, even though it's at a higher level. Think putting your finger over the end of a soda straw and pulling it out of the cup. You have a straw full of soda, but it won't flow out until you let some air in the top. Same with your fuel tank. If you hear air rushing in when immediately removing the gas cap after it dies, it's because there was a vacuum in the tank created by the fuel going out but no air coming in to take its place.

Yep, as soon as I started reading your thread I knew exactly what you meant. Thanks for setting me straight.

You have a problem with fuel delivery. I won't recap all the advice given here but don't spend a lot of $ replacing stuff that doesn't need replacing. Sounds like a blockage problem. A slightly lower level in the tank would not affect the carb or the float level. Runs OK on a full tank? cap vent, junk in tank, tank bulb & screen. It's somewhere in that area.

If you have a standard sediment bowl under the tank there is a vertical screen in the cap facing the engine and it could be plugged up. Do not remove the gas line at the cap and poke into the hole to make gasoline come out. At that point you have made a hole in the screen and it will no longer work properly. There is a ledge cast into that front hole to keep the gas line from poking through the screen. This set up works wonderfully if kept clean! .....

If the pipe has minor bumps in it, it will allow air to accumulate in the pipe and cause fuel starvation. The Ford Bulletins describe how the pipe should be routed and sure enough it drops very slowly to about the engine arm and the turns up to the carb. This way no air pockets can accumulate. Most cars I’ve seen run a pipe almost horizontally with bumps all the ways. Air locks waiting to happen.
On my coupe I ran a slightly diameter pipe as described in the Bulletin and have never had a problem.

Forget the plastic (or any other material) in line fuel filter and fuel pump. They look terrible and unnecessary.
Steve summed it up correctly however I do convert my system to 5/16. Any larger is pointless as carburettor orifices are smaller anyway
Alan

I've never subscribed to the high spot in the line being an air pocket theory. Yes, there could be some air but I don't see it as a problem. As a matter of fact, I think if you disconnected it from the carb and let it flow, it would purge all the air out anyway and unless you ran the tank dry, it would stay that way. And if there were some some air in there, I don't see the problem. It's no different than the trap under your sink or toilet. There's plenty of air in high spots in those systems and they flow just fine. The only time I see air trapped in there being a problem is if it were somehow to become pressurized and prevent the fuel from flowing down from the tank, but I don't see how that could happen. As soon as the carb needed fuel, the float valve would open and any pressure would immediately be relieved through the carb. As long as the high spot in the line isn't above the fuel level in the tank, I think it will flow just fine.

Physics. As long as the source is the high point, ups and downs don't matter. I could route a fuel line all the way down to the ground and put a dozen coils in it, and as long as the tank is higher than the carb it wouldn't matter. The pipes from the water tower to your house go through a lot of ups and downs, and you still get your water.

Good day everyone...just an update. Cap was open and clear, sediment bowl drain petcock flowed fast and got I got a little fine sediment in the coffee filter but nothing that made we think WOW this is the problem. Also was letting the gas come out of the bottom of the carb and that was flowing decent. I cleaned the sediment screen which was open but cleaned it anyway. So then I was laying under the car wondering what my issues were since everything was so free flowing and overall clean......I dug in deeper. Removed the brass fuel line and cleaned it out, seemed normal. Got to the carb and disassembled from bottom up, bowl was clean but low a behold....some ethanol gunk in the jet....darn ethanol. cleaned and blew out with air and the hole became large and open.

Putting in some non ethanal gas and will take it for a rip...will let you know.

okay, back from test run. Idles perfect and runs great until the bowl empties. I back off the throttle and the bowl fills up and I'm able to keep going but at that point I lost all momentum and don't have the power to regain the hill with any kind of authority, just happy I made it up.

Going down hill, the bowl starvation doesn't seem as bad but going down the grade with throttle wide open it wants to sputter....not getting enough fuel but I'm confident that it's not tank to carb....at least I think I'm confident. :-)

I messed around with the lean/rich knob and that seems proper. Turn each way to much and it stalls out. Interestingly, it backfired when I shut it down...never did that before but then again, I was messing with the richness right before i shut it down.

I guess now I should go into the carb more in-depth to investigate float and needle which I didn't do. Just took off the bowl and unscrewed the pilot. Am I on the right path to think that ethanol could be built up around the needle which is slowing down the fuel into the bowl?

I've heard tale of the fuel line going so far up into the fittings on either end that it blocks fuel flow. Some fittings have a stop built into them. Others not. But you say you have good flow out the bottom of the carb? If you have a good heavy steady stream of fuel coming out the carb drain then I can't see how you can have a fuel delivery problem. What would cause it to flow correctly into the bowl when sitting still, but not when going down the road?

Float set too low?

Carb vent dirty/plugged?

Did you varified all the passages where clear too?

My simple advice is to keep your wallet in your pocket until you KNOW what is wrong. Then spend money only on the part that is causing the issue - don't over think this or you will put in future problems. The T is the MOST DEBUGGED car on the planet at 15M+ of them built. Every stock Model T problem I have ever heard of on this forum was found and fixed many times before most of us were born. We fall victims to our own thinking that the people who built these cars didn't know what they were doing on any part of the car that is up on the forum for debate. There are known issues with T's but I think most of them are electrical. Fuel flow was a much bigger problem then with the gas they had versus what we can buy so you don't need to redesign the fuel flow system - just find out what is stopping the gas flow and unplug it or replace it but the stock 3/16 I.D. fuel line can provide all the gas you are going to need even if you run a steady 40 MPH for 3 hours which is way more time than it will take to drain a full tank if you drain it on the ground at the carb end of an open disconnected fuel line when all is correct with the flow at that point. If you have a good flow there then your problem is in the carb/motor

Good hunting!!

Along with the other thoughts, it sure is worth a look Scott. Sluggish needle action: Some time ago at work I had a really odd running, brand spanking new 18 horse air cooled engine.
I started messing and found a shard of plastic from a machining operation upstream along side the needle.
Goop or a bit of something sure can mess it up.
Mr Jelf found an issue on one of his carbs where the float hanger/mount was tweaked and the float itself was dragging on the bowl.
I must've found something similar when I was a kid (I sure as heck don't remember) but thru force of habit, every time I put a carb together, I gotta tip the carb up and gently rock it and listen for the clunk/tink of the float moving back and forth.
:-)

WHICH shut off needle do you have in the carb? Sounds like everything is new up to the carb, correct? If you have the Grose valve take it out and replace with proper needle type valve. If you have the proper needle valve look for an obstruction at the inlet. The other possibility is, something has fallen in the tank is is covering the sediment bowl opening.

Hey folks, so after taking care of some much needed outside work, I took apart the carb which I was told is a NH.

Took out needle and cleaned, float doesn't seem adjustable, and I believe there was the Grose Jet which has some stainless steel balls inside. There didn't seem much play in them when I shook it back and forth so I cleaned that hard as well. Sprayed down every nook and cranny there was to be cleaned. Popped it back on and went down the road.

At first run it was sputtering a tiny bit but with each grade pull and drag I did it sputtered less and less which I believe had to do with the bowl still filling up? By the end of my test runs, I'd say it was back to 85-90% of what it had been.

I don't know the physics behind the Grose Jet, but does that allow as much fuel in as a normal main jet?? Sounds like the overall opinion of the Grose jet is that it stinks....are there different size jets I should get for replacement or are they all the same size. Like cycle/quads etc.

Either way....I had the smile back on my face!! ;-)

Scott, you're correct in that Grose Jets stink. I had one in my '14 with a Holley G carb. and it would either flood or not start at all. Replaced it with a stock needle and seat from R V Anderson and all is well. I understand that the Grose Jets are worst when used with the Ethanol gas.

I'm glad you got it fixed.

Keith

I haven't used a Grose jet because they have a reputation for getting stuck. Some people have great success with the neoprene tipped needles, but I've had a couple of them stick so I use the original style.


I put it in a drill and run it against a stone, then 600 grit paper, then 1500 grit.


I run a piece of poplar dowel in the seat to make sure it's smooth.

Once the float valve is in the carb, tap the needle with a small hammer to seat it.

You adjust the float by bending the little arm that shoves up on the needle.

You could say the main jet is adjustable, the spray needle adjust the amount of fuel that passed thru it. Only come in one size. The float is adjusted by bending the metal tab that rubs on the bottom of the needle fuel valve.

The name "Grosse jet" is misleading. It's not a jet at all. It's just a float valve. Even the term "Needle valve" is misleading, as the spray needle and main jet could be considered a needle valve.

Lots of people have had trouble with those "Grosse jet" float valves. I was told the NH in my TT had a Grosse jet when I bought it. I dont know if it does or not, but it runs well. Until it dont, I'm not messing with it. If i had a carb problem, that's the first place I'd look, though.

I opted to put a Holley "G" on my '13. The carb I acquired had a Grosse jet float valve which I changed back to the original. Seems to me the Grosse valve is unnecessarily complicated, may be restricted flow compared to original parts, and certainly looks like the sort of item that would fail if "crud" in the fuel, gelling or "varnish" occurs. Of course all of the above can befall the original setup, but it's easy to correct.

The replacement needle and seats used to be a problem, and the opening in the seat was too small. We solved the problem by making and exact replacement. We had 2000 made, and they are all gone now. As I recall, the replacement seats were .100, and stock is .125".

FWIW and not jumping into the MMO controversy, I put a small amount of 2 stroke oil in my gas, maybe a cup to a tankful. It burns well and lubricates the cylinders when the car sits, acts like fuel stabilizer, and I believe puts a thin film of oil in the carburetor and on the needle valve to prevent corrosion and sticking if the car sits for a while. I recently helped an older gentleman get his 1922 fire truck going after 5-10 years and the NH had a Grosse valve that was corroded and stuck closed.

Hey gang, took the T out for a lengthy ride and it performed very well. Never hit fuel starvation once...only on a real real long steep hill did it start sputtering but that was with around 3-4 gallons in the tank and if I backed off the throttle it kept on chugging. Hard to be disappointed with that. :-)

We had it in Ruckstell high on a flat and my son GPS'd our top speed at 41mph on a flat and 49mph down hill. Don't worry, I'm not a speed racer just wanting to see if the carb would keep up....and it did.

I'm attributing all the issues to ethanol gas and the Grose Jet balls sticking from the ethanol. Probably wasn't bad idea to give it a total cleaning anyway. Happy motoring!!!

That sounds great Scott!