74 Ford 3000 fuel (gas) system plumbing

I have a '74 Ford 3000 with a gas engine. It's a great tractor that was in need of a lot of TLC when I got it. One of the issues is that between 1974 and when I got it, someone decided to convert it to gravity feed. That wasn't a high priority on the fix it list until I noticed some spitting, sputtering, and eventual stalling when it would get low on fuel and I was going up or on the side of a hill.

I have no idea why they would do that since the fuel pump seems to work - has suction and pressure when removed and cycled manually. No idea if it's producing the right amount of fuel pressure or if it leaks since I don't have the plumbing complete as of yet. They didn't even do a good job when they converted to gravity feed. They cut the line coming from the tank, cut the line going into the carb, and spliced the two with a rubber hose with a plastic shutoff valve. They removed and discarded most of the other bits in between including the sediment bowl. They didn't even put another filter in the line!

Hasn't been a big deal to replumb - 5/16 steel lines with standard double flare fittings (1/2" - 20)(male, just like brake lines) - the flare nut that goes into the tank shutoff valve needs to be one of the ones that are longer or it won't seal. I didn't realize that until I was making the lines. I had to make up the difference with O-rings for the time being. So, no problems. That is, until I got to the line going from the sediment bowl to the carb. I can't figure out what those fittings are. The one from the sediment bowl is the same as the one going into the carb, with the exception that the one into the carb has a screen on the NPT side that threads into the carb (no idea what NPT size, 3/16 maybe).

I can find the fitting (377733S36 [$19.00]) and seal (377732S [$17.50]) in the New Holland catalog, I just can't see paying almost $40 for what I should be able to find for around $5 or $10.

I've rebuilt the Zenith carb with a complete kit from Mike's Carburetor Parts, added a sediment bowl from Yesterday's Tractors, and replumbed all of the missing lines with the exception of the one that's giving me problems.

I would greatly appreciate it if anyone knows an alternative or what type and size these fittings are, and is willing to share that information.

Most likely the threads in the carb are 1/8" NPT. That will actually measure around 5/16", as the size roughly refers to the ID of the fitting. Finding one with a screen tough will have to come from a carb shop or the dealer.

The orings you added to the other fitting, probably not going to work. Keep looking until you find the right fitting. Short cutting fuel lines over a hot engine, with a gravity feed bottom tank fitting, not a good practice.

But as for using the old pump, even though it appears to work, I would go ahead and replace it. If it's been running open, no fuel through it, dirt and whatever that may be inside, dried up diaphragm, asking for trouble trying to use it.

Not only will it release whatever is inside into the carb, if (when) the diaphragm goes, it can fill the crankcase with gas, and drain the tank on the ground, or worse!

The old mechanical pumps don't like ethanol gas to begin with, so please, start with a new one, not worth the chance!

You might want to consider an electric pump, the smaller the better you only need a couple of PSI. How about a rubber fuel line, pretty easy

Those 3 cylunder gassers did take a rather circuitous route from the tank to the carb didn't they.
But those engines were first designed to be diesel and kind of as an afterthought made to run on gas. About the only place to put the fuel pump on them was on the timing cover so that's what they did.
I think the threads that go into the sediment bowl and into the carb are 1/8" NPT. The other end is like a compression fitting that uses a rubber ferrule inside the nut. About the only place I've ever seen them is on these Fords.
I do have a pair of those fittings here that I would give you free if you want to pay the shipping. Would throw in the correct inlet pipe that loops around the throttle and governor rods too if you wanted it. Same price.
The fittings would go in a $7.50 Flat Rate box. If you wanted the pipe too it would have to go into the next size larger box $12? $15?
Those 3 cylinder Fords are my favorite tractors. I have 3 of them. But I got tired if dinking with carbs and points so mine are all diesels now.
By the way, welcome to YT.
There is a very good Ford Board here. Bunch of knowlegable guys there.
I would post your Ford questions there instead of here.
Email me with your contact info if you want these.


Cluck here for the Ford Board

Thanks for the response. 1/8 NPT? Could be. The 5/16 is the tube size of the lines, I'm certain that isn't the size of the NPT fitting into the carb or sediment bowl. You are most likely right on the 1/8 NPT. It's been a very long time since I've dealt with pipe, and even then I didn't work with small pipe. Either way, I don't need the one into the carb or sediment bowl, just something that will fit the other end of those two fittings. That said, now that I have pretty reliable information, thanks to you, that it's 1/8 NPT, I may be able to find another fitting that will work and isn't as expensive.

As for the O-rings, yep, they probably will fail. I just need them to hold until I see if I've fixed the spitting and sputtering. I can bend a new line with a longer nut in a matter of a few minutes (after I get the longer nut that is.) I was very careful not to route the lines around anything too hot. I'm fairly certain I routed the lines pretty close to where they were originally (based off of diagrams and use of my brain housing group.)

Thanks for the advice on replacing the old pump. I'm not as worried about it putting crap into the sediment bowl, but certainly wouldn't want it dumping gas into the engine via the timing cover. I will probably rebuild it instead of replacing it though. Especially since winter is coming, this site has the kit, and I'm a bit of a tinkerer.

Thanks again. Very good information!

The electric pump and rubber lines might work. The only issue I have with that is that I kind of want to keep it as designed with as few changes as possible. I do still use it as a working tractor, but want to kind of bring it back to its factory originality. If that makes sense. There's really no urgency to get it back in the field so I can take my time and use steel tube, brass fittings, and mechanical pump. Maybe I'm just hard headed.

Thanks for the alternative though. I'll keep it in mind if I can't get it done the way I'd like.

Fantastic! Thanks for the welcome, the offer for the parts, and the better location for my post. I'm not sure how I missed the Ford forum. My view must have been blocked by my colon. LOL.

I had no idea these engines were initially designed as diesels. Very interesting! That would help explain these fittings. I found a nut that I think would work, in an Eaton catalog. It's called a diesel nut! It's for 5/16 tube and has a 5/8-18 thread (part number 8112x5). Measuring the male compression/rubber seal fitting, I'm thinking it's the right size, but can't be sure without having one in my hands.

Yes, the fuel lines are all over the place! Fortunately, I have a little experience with figuring out how to route pipe (or in this case tube) from my time as an HT in the Navy. GO NAVY!

As Steve suggested, although before he suggested it, I routed the lines away from anything hot to reduce the chances of vapor lock. Fortunately, some of the tube from the tank to pump was still attached to the tractor so all I had to do was plumb from the tank shutoff to the remnants of tube to the pump. Then from the pump down to the bolster, across the timing cover, and back to where I'm placing the sediment bowl. A lot of measuring and bending, but it was a lot of fun! At least until I got to the fitting I can't identify.

I will certainly take you up on the offer for the fittings and tube. I don't really need the tube, especially since I probably don't have the sediment bowl in the same place as the factory. But I'll take it because I may bend some new lines to bring it closer to original routing.

I'll hit you up with a PM to coordinate for the parts. Thanks again.

You are probably way beyond the need for these but I have a couple photos of the original lines on one of those tractors.
Jerry
MR2 USN 71-75

One more.

We seen them still pump fine but leak into the engine oil,, might be why they deleted it the way they did
cnt

Oh yeah, way past that point. But, it looks like I plumbed the tank to pump correctly. At least in the front of the engine. The line from pump to sediment bowl was still attached. Thanks for the pics, they definitely validate my work.

So, you were an MR2 in the early '70s. That's right about the time the HT rate came into existence - '72. One of my best friends while I was in was an MR. We hung out while we were in common core, A-school - after classes of course, then were assigned to the same ship. I was assigned to the pipe shop at first, then went to NDT C-school and was on a permanent TDY to QA. It was kind of strange being in boot camp at 29. The Company Commanders didn't give me much grief since I was older than them, and all of the other folks called me grandpa. Ah, good times!

You know what they say...if you're not engineering, you're a passenger! LOL.

HT2 (SW/AW) Blythe
CVN75 '99 - '03

Correction: This site does NOT have a kit. Looks like I'm buying a fuel pump.

Interesting, sounds like it may be a fairly common problem then. It looks like I'm going to be replacing the pump anyway. I'll just have to keep an eye on it to see if it starts to leak into the oil.

Ultradog, I tried to send you a message using the email function on here, I'm not sure it's working though. If you want to send me an email, we can sort out the details about those parts. My email address is [email protected]. I won't be able to get it if I'm at work (1300-2200).

Thanks again,
Kirk