More Carter YF-938SD problems

[Nemo von Klepper]

My CJ3B is finally showing signs of life.
After going through recommended long dormant engine restart procedures, I started cranking it. The carb flooded badly, actually dripping over the side--at least I know I don't have a pump problem, lol.

I wasn't even getting a hint of combustion even if I disconnected the fuel and used starter fluid. I decided to check the ignition, resetting the points and spark plug gap. This time when I used fluid it fired at least 4 or 5 times before sputtering out. At least the ignition seems responsibly within range.

I reconnected the fuel line and immediately flooded the carb again. My understanding from my service manual is that the float needle prevents the bowl from overfilling. Presumably my float height is improperly adjusted. I used a 5/16ths drill bit to measure the spacing, but I presume it's set too high.

Am I on the right track? Presumably I need to lower my float just a tad. I'm still surprised so much fuel is leaking out. I'm inclined to think the float needle isn't closing at all.

[gmwillys]

Also check to ensure that your float is actually floating. A sunk float will cause you all sorts of heart burn. Another thing to check is that the needle itself isn't cobbled up. If the needle has a rubber tip, often if ethanol fuel is used, it eats up the rubber tip.

[Nemo von Klepper]

Thanks,

I recently rebuilt this carb, so the needle is new. The float moves freely, but when I pull the carb apart, I'll check to make sure it doesn't have fuel inside (?).

I think I may have misunderstood the instructions in the manual. It stated not to force the float down (up). I interpreted this to mean that I should set the float so that the needle spring pressure just allows the float to rest on the gauge with the top inverted. Thinking about the flooding, and how this might work in a toilet tank, for example, where the valve didn't shut off, I'm thinking that with the needle in closed position (pushed closed), the gauge should measure the gap between the float and the carb top.

[LarrBeard]

I think I may have misunderstood the instructions in the manual.

Cjeck this:

https://www.youtube.com/watch?v=8FqEjQsJfIU

Mike's Carburetor Shop has a lot of info about the Carter YF series as does the CJ2 Forum.

[Nemo von Klepper]

So...
According to that video, it's definitely a problem with the fuel not being closed off.

I pulled the carb apart. This is what I can't figure out, the vast difference between the float adjustment of my old needle and seat and the new one.

With the new needle seat, the one that floods, the float can be pushed all the way down until it actually touches the bowl cover.

Since the keep actually ran with this needle & seat previously, I decided to adjust it as close as I can.

With the old needle & seat, I can't even push the float down far enough to reach the 5/16 feeler gauge. Resting on just spring pressure, inverted according to the instructions, the top of the float rests well above the feeler gauge.

Since my keep actually ran with the old needle & seat without flooding, I decided to reinstall the older set, adjusting as close as I can "Allow the weight of the float to rest on the needle and spring. Be sure there is no compression of the spring other than the weight of the float (Service Manual, 98)".

Now it's not flooding, but it's still not starting either, even with ether. I'll give it a try later with ether.

[Nemo von Klepper]

It's Alive!!!!
It ran for 30 seconds until I pushed the choke back in. I probably should have waited.3089

It's still flooding, but at least I'm narrowing on the target.

[gmwillys]

If the engine ran with the choke pulled out, but not when pushed all the way in, is that the engine is starving for fuel. The choke limits the air flow going in, and the vacuum pulls more fuel. Spend some time to go through the adjustment screws. The air/fuel mixture screw is too far in, or there may be crud in the port. You are on the right path. I've had issues with aftermarket carb kits as well. The parts are close, but rarely set the same.

[Nemo von Klepper]

Well, I managed to get it going again and it ran for about 3 or 4 minutes until my improvised Coke bottle gas tank ran out of gas.
I couldn't get it started again. This is a multi variable problem. It wouldn't start even with ether, so it seemed to also indicate an ignition problem. The spark was weak and orange so I decided to start eliminating variables in that department. I happened to have a spare Bosch coil out of my Saab C900 parts car that fit. That did it. The jeep is now starting with ether consistently and running on gas until it floods out after about a minute. At least now I don't have to throw any ignition parts at it for the time being.

After initial flooding with the needle & seat sent with the rebuild kit, I swapped for the older one. Getting the float adjusted right with that one was a pain, there's no criteria for gauges: It's completely out of service manual specs and bend the lip too far one way and the bowl doesn't fill; too much the other way and it cascades over the sides, all while eyeballing the difference in the lip.

I decided to put the needle & seat from the rebuild kit back in; it matches the illustrations in the service manual for the Carter YF SD. Tinkering so much with the float gave me a pretty good feel for how it works. When the bowl flooded, there was no pressure in the fuel line. When the engine stalled and no fuel was in the bowl, the line was under pressure. I might have a fuel pump pressure problem. I might try an inline pressure regulator later.

For now I decided I needed a graduated way to gauge my float height. Since my bowl was flooding with a 5/16th gauge I decided to go up to 3/8. I used a wood spade bit. That did it. The jeep now runs until I switch it off. No fuel dripping down the outside of the carb throat, etc. The motor also accelerates evenly, giving me an idea that the carb low and high speed circuits are close to spec. Now at least I have a new reference point.

The jeep is backfiring quite a lot, but I image refining the timing will help.
Note to self: I'm definitely going to need a new radiator. This one leaks like a sieve.

[LarrBeard]

"I might have a fuel pump pressure problem. I might try an inline pressure regulator later."

Well, you are getting into the swing of working on old Jeeps. You will often work two or more problems at the same time.

As for fuel pressure; the Carter YF does not need much fuel pressure, a couple of pounds is plenty. We found that new fuel pumps can deliver a lot more pressure than floats and needles can regulate. We had similar flooding problems and ended up with a regulator in the line. It ended up being set at about 1 1/2 pounds and that's plenty of fuel for the F 134.

This one works well and it doesn't break the bank:

https://www.autozone.com/fuel-systems/fuel-pressure-regulator-and-control/mr-gasket-1-to-6-psi-fuel-pressure-regulator/833011_0_0

In the picture we're verifying fuel pressure; you can see the regulator in the carburetor supply line.

Resist the temptation to pour some stop-leak in the radiator. I've had mixed luck with such products and in the end they have caused more issues with thermostats and overheating than they have fixed - but your results could vary.

[gmwillys]

I agree with LarrBeard, time and money spent fixing the radiator correctly now, will keep you from having troubles later.

[Nemo von Klepper]

Thanks, I've been off line a little while now, but I'm back.

I absolutely agree about the fuel pressure regulator now. I ended up getting a Holley 1208, offered by KW. It has a range between 1 to 4 lbs. The instructions indicate that the pressure can effect the float height, so I'm confident that I'm on the right track: set the float height as close as I can to factory spec and then adjust the fuel pressure to as close as I can get to 1.5 lbs.

Any recommendations on where to mount it? I was thinking of someplace near the carb or mounted to the fender opposite of the fuel pump.

Re: the radiator: Thanks for the tip. I wasn't so sure. All the stuff I could find on the web only indicates stop leak is good for emergency fixes. I also had a friend that completely screwed up his newish Ford SUV. My other collector cars are Saab C900s and I wouldn't dream of putting stop leak in them--way too much precision engineering. Because the Willys are so rough 'n tough, I thought they might be able to take it. Thanks again for the caution.

[LarrBeard]

Any recommendations on where to mount it? I was thinking of someplace near the carb.

In the '48 we put it just under the fuel filter - which you can just see in the attached picture - and that kept it out of the way. The Mr. Gasket regulator works very well and isn't all that hard to tuck away.

Looking back a bit - we probably should have put the filter first in line to keep any crud out of the regulator ..... duuhhhhhh.

[Nemo von Klepper]

Ok, that's good info. I'm still in the process of getting this thing running. I've had the jeep sipping gas out of a gas can: plastic gas can> rubber gas hose> fuel filter> fuel pump> rubber gas hose> carb. Because of my float/pressure problems causing flooding, I decided to put in a pressure regulator.

I plan to go ahead and install all new factory spec fuel lines next month if I can get it fired up this month and fix the pressure/flooding problems. On the 3B, the setup more closely resembles a 5 than a 2B, I think. Anyway, the previous owner put in the wrong fuel pump. I need a dual action to operate the windshield wipers (unless of course any of you would have any reason to advise against vacuum wipers). The setup for the 3B and 5 had a sediment bowl in the pump, I believe.

I'm sort of inclined to run the fuel line: Steel tank> steel line> dual action pump w/ bowl> flex hose> fuel filter> flex hose> pressure regulator (mounted on the fender)> flex> steel line> carb.

[gmwillys]

With the cost of a double action fuel pump, I would install a filter before the fuel pump. I have one on the frame rail, just past the steering box. If you have a good tank, and clean fuel lines it's not a big deal, but odd things end up in fuel tanks.

[Sebastian21]

I am intalling a Carter YF on my F 134 1961. The solex keeps flooding. Bought a rebuilt Carter off ebay. Received it and as soon as I saw it I knew it would not work. The choke linkage was on backwards. I could also see the accelator pump was not working. Have to rebuild to use. Just because you buy a part " rebuilt to factory specs" check it over before you install. I am going to keep it because I need the body.

[Sebastian21]

The ebay seller said he is sending a rebuild kit. It is nice to know that some sellers stand behind their product. Should only take hour to put carburetor in working condition. Will see if a Carter will solve the flooding problems of the Solex.

[LarrBeard]

[QUOTE=Sebastian21;6105Should only take hour to put carburetor in working condition. [/QUOTE]

You had mentioned that there were issues with the accelerator pump.

I had an adventure with the accelerator pump on my YF. There are two coaxial springs on the pump diaphragm shaft that want to go zinging all over the shop when you replace them. The are called Da**it Springs because that is what you say when they take off. The little clip that holds them in place is also sometimes called a da**it clip - for the same reason.

There is a block secured to the carb body with four screws that holds the accelerator pump diaphragm in place. If the diaphragm was not replaced, the old diaphragm gets really sticky and glues everything in place. I used an industrial heat gun to get things to come apart on my YF.

I hope you have an easier time...

[Sebastian21]

you nailed the problem exactly. One of those spring was missing and the clip was gone. When I get the rebuild kit I think I will do it inside a box so I do not have to chase the springs so far. Thanks for the heads up.

[LarrBeard]

More than you would ever need to know about the Carter YF.

https://www.cj3b.info/Tech/Carburetor.html

https://www.cj3b.info/Tech/CarbsDave1.html

[Nemo von Klepper]

Good luck with the rebuild. I had mine blow apart, but luckily they didn't take out an eye or get lost.

So...
I installed the pressure regulator to hang off the carb with a couple L brackets. It's not pretty yet, but I can probably fabricate a prettier one later after I get these bugs ironed out. The pressure regulator solved my flooding problems right away. The engine runs as long as I want and I can shut it off with the switch.

Now I just swapped one problem for another: The pressure regulator has three 3/4"ports: one in, two out. I plugged the one and reduced the others so that they will accept the standard pressure fittings. This thing is leaking rather badly, which is why I shut the engine down sooner than later. The pressure fittings seem to be ok, but the reducers and other threaded locations seem to be suspect.

Anyone have a thread sealant they can recommend? If this were regular plumbing, I would have used teflon tape. I didn't because I was afraid of it melting and gumming up my carp, etc. I've also red that even yellow gas tape can have little pieces break off and jam the float valve, etc. I think some sort of thread paste is wanted. Anyone have any recommendations?

[gmwillys]

We use loctite 567 thread sealant on all our pipe thread fuel fittings, with no issues. It holds up to JP8 and diesel fuel.

[Nemo von Klepper]

With the cost of a double action fuel pump, I would install a filter before the fuel pump... but odd things end up in fuel tanks.

Thanks, I agree. I was going to add a sediment bowl on my system with my current fuel pump until I realized the dual action has a sediment bowl and I would need that fuel pump for my vacuum windshield wipers. Honestly the reason I am still sipping the gas out of a plastic gas can is that I don't trust that the tank doesn't have a hornets nest in it that would just clog my filter. I'm trying to keep problems at a minimum at this stage, until I have that engine tuned and ready to roll. It's a thought to just add a filter in line ahead of the pump regardless, the way I have it now--they're cheap enough.

[Nemo von Klepper]

We use loctite 567 thread sealant on all our pipe thread fuel fittings, with no issues. It holds up to JP8 and diesel fuel.

Thanks, that's good advice. I did a little more research and it turns out a lot of boaters use Permatex Aviation Form-A-Gasket No.3 for this kind of problem. A pint can costs $8.

[gmwillys]

There are two useful ways to clean a gas tank, to ensure that you don't have crud in the tank;
1. Have a radiator shop hot tank the gas tank. Cost depends on the shop.
2. Use fish tank gravel and shake vigorously. The gravel is a bit tedious, and tough to get all the rocks back out. It isn't impossible, because the tank isn't baffled.

Both methods would best be followed up with a gas tank sealer. Redcoat sealer works well, and lasts for a long time, if not forever. The sealer smooths out any rust spots, and prevents new spots from forming.

[LarrBeard]

Teflon tape does not dissolve or deteriorate in gasoline - it's OK for making up joints if you don't have the Loc-tite or Permatex stuff.

[Nemo von Klepper]

Redcoat sealer works well, and lasts for a long time, if not forever. The sealer smooths out any rust spots, and prevents new spots from forming.

Thanks for that advice. So I was looking at some videos about application. It seems the instructions require the tank to be rotated for 3 hrs to keep the sealer from pooling. I was wondering if this is a constant rotation, or come back every 30 minutes and agitate it? If it's the former, you would just about need a gimbal. Obviously the same gimbal would work great with your fish tank gravel. Any thoughts?

[gmwillys]

When I did the last tank, I rotated the tank until there was a good coating all over. Then go back every 5 to 10 minutes and repeat. On the first Jeep tank I did, I turned it more often, since it was light. On the bigger military tanks, it gets tiresome quickly. Just keep a close eye on it until the liquid dries.
You want to ensure that the top of the tank gets the most attention. Rust forms where gas isn't, so rust flakes that clog the filter comes from the top.

[Sebastian21]

Why clean a rusted tank? You will be dealing with pin holes that will continue to give you problems. You can get a new tank for 175.00.

[gmwillys]

True, the CJ tanks are relatively cheap. The military tanks, (M38, M38A1, M151, A1-A2) are not cheap. I have only had one M38A1 tank that sat open that was too far gone to fix. Most tanks that I have dealt with have rust scale on the upper sections of the tank. The best cases/easiest fixes were the ones that had old varnished gas in them. Depending on whether there was a cab installed, or the heep was kept outside in the elements. Sometimes there are pin holes in the top, and aren't too difficult to patch. It isn't hard to braze, or weld in a patch, then pressure test. After that, then apply the Redcoat. In my opinion, I would put the Redcoat in a brand new tank.

[gmwillys]

One thing I didn't think about, was the heat riser vane in the intake manifold. The guy that runs the old Jeep carb website posted this;


.
Post by scoutpilot on 3 hours ago

Without a properly functioning heat riser valve, going after the carburetor will frustrate the living heck out of you. If the valve is stuck in the open (cold) position, heat from the exhaust will continuously bathe the bottom of any carb you put up there. The heat will cause the gas in the bowl to boil. The resulting pressure will force fuel past any metering device and flood the manifold.

[Nemo von Klepper]

Without a properly functioning heat riser valve, going after the carburetor will frustrate the living heck out of you. If the valve is stuck in the open (cold) position, heat from the exhaust will continuously bathe the bottom of any carb you put up there.

This is definitely something to keep in mind when I get to the point the engine stays running long enough for this to potentially happen... :confused:

Speaking of vapor lock, I finally mounted my pressure regulator to the driver's side fender, near where the lower radiator hose passes by. I installed factory style fuel lines. Off the fuel pump I ran a flexible fuel line with compression fittings to the regulator intake port. I used the flex line from the fuel line kit to run from the regulator output port back to the carburetor tube next to the fuel pump. No alterations in the fuel lines were necessary.

Where that flex line was originally supposed to be, between the fuel tank line and fuel pump intake port, I've set up with barbed nipples on both ends. I've used regular fuel hose with hose clamps and I have the fuel filter in line here, right before the fuel pump intake but after the steel line from the fuel tank.

Question: One of the flex lines to the pressure regulator passes about 4 inches from the exhaust manifold. Is this too close and a potential source of vapor lock?

I am guessing "no" for now since the regular fuel lines pass within this distance to the exhaust lines and the fuel pump.

[gmwillys]

No, the rubber line also acts as an insulator. The exhaust really doesn't put off enough heat to cause vapor lock, unless you are running hard in the heat of summer. I've never put much thought into the heat riser, and haven't checked to see if mine even moves. I figure it's rusted shut, but wouldn't bet on it.