1948 Farmall Cub - stored and not running

[Jimmymike]

......It's getting a good flow of filtered clean gas .......

Do you have an in-line fuel filter added? If yes, perhaps it is restricting fuel flow just enough at the low idle to shut it off. Just a thought.

Or even the factory screen in the carb inlet? Good luck.

I do have both, inline and factory screen. After it stopped the first few times (both slow and fast idling.) I took both apart and both were clear, screen and inline filter. Checked the flow to the carb by disconnecting at the carb fitting and it had good flow there also. But when running under load I would assume the engine would need more fuel than when idling. But when running up and down the road it runs fine.

[Mike in Louisiana]

Just a SAFETY note since you said you live in hilly country, keep the left side on the up side of a hill. They will turn over pretty easy on side hill. BTDT.

PS Welcome to the forum.

[staninlowerAL]

I do have both, inline and factory screen. After it stopped the first few times (both slow and fast idling.) I took both apart and both were clear, screen and inline filter. Checked the flow to the carb by disconnecting at the carb fitting and it had good flow there also. But when running under load I would assume the engine would need more fuel than when idling. But when running up and down the road it runs fine.

Are you using a "rubber" type hose for fuel line? I have had those to swell inside and restrict the flow. Preferred metal (5/16 brake line) is best IMHO, but if you use a flex line, make sure it's rated for gasolene. If your carb still has a factory screen in the fuel inlet, there could be sediment build up there that's restricting the flow. Better to open the drain on the bottom of the carb and let about a quart flow from there to ensure the needle valve and seat are working properly and no restriction in the fuel delivery system to include the shut off valve on the tank. Also check the vent on the fuel tank cap for restriction which will cause the tank to operate under a slight vacuum if not properly vented. BTDT

[Rick Spivey]

Not sure, but I wonder if having the idle mixture wrong (too lean) would cause it to cut off when idling for extended time. That is the screw on top of the carb at an angle. It is adjusting the flow of air, not gas, so in is rich, out is lean. You might try adjusting that; we normally look for no black smoke at idle, and it should run straight up to full speed without any stumble or hesitation. If that has no effect on the Cub whatsoever, your circuit might be clogged (two very small holes in the carburetor throat or venturi area), and I had one that had the wrong screw (some are more blunt, others more sharp). Just a thought.

[Jimmymike]

I adjusted the carb to it's happy medium but it still may be to lean. I don't see any signs of black smoke when running or idling. I also checked the fuel line to make sure it is free and found good flow. The fuel line is metal except for two very short pieces of rubber fuel line that connects the in-line filter between the fuel bowl / stainer and carb. I did change the original fuel cap to the IH replacement I received in the mail. I will change back to the original and see if that has any bearing. Like I said, when running the tractor up and down my very hilly road the tractor runs great in all gears. When in a pull the governor picks the engine up and lets off when satisfied. Throttle works well with no hesitation when increasing engine speed. Runs fine in every other respect except when idling. The idle is smooth then after less than a minute the engine just stops. I guess the Cub is trying to reduce it's carbon footprint in it's own way ?

[Don McCombs]

When you disassembled and cleaned the carburetor, was the idle tube present or missing? It's the vertical brass tube above the black arrow in this photo.

[Jimmymike]

When you disassembled and cleaned the carburetor, was the idle tube present or missing? It's the vertical brass tube above the black arrow in this photo.

Yes it was there. I cleaned with carb cleaner and blew it out with compressed air. All seemed ports and cervices appeared to be clean and clear. When I took the carb apart for the first time I was amazed how clean it was. After sitting for many years I thought it would be gummed up. I talked to the gentleman I bought it from and he thinks he cleaned it when it wouldn't start a few years ago. I think he was thinking correctly. I reassembled the carb using new gaskets. I did have to make a replacement mounting studs to attach the carb to the intake manifold. My friend had stripped the threads out of the carb when he last tried to clean and remount it (I guess). I had to tap the threads to 5/16" to fit a new studs in the carb. On the manifold end of the new studs I turned them down to 1/4" and threaded it to 28nf to fit the holes in the intake manifold. Both mounting studs pulled up tightly against a new mounting gasket.

[Jimmymike]

I have a question about the oil breather / oil filler cap. Does this cap fit real loose? Mine is so loose I think it would be easy for something like a limb or something brushing up against it could make it come off. All the old cars I've worked on with breather caps had a "spring like deal" on the inside that would slide on the filler tube to hold the cap in place. Am I missing something on this cap or are Cub breather / filler caps made to just lie in place on the filler pipe?

[Bigdog]

The fit should be snug. The large cap should fit well down onto the filler tube.

[Eugene]

what would cause it to just stop running at idle when it is running so smooth?

Back side of carburetor is a set screw on a bracket. Set screw controls the amount of opening in the carburetors butterfly/throttle valve.

Give the screw 1/4 clockwise turn and see if that doesn't solve the engine dieing at idle issue.

[Jimmymike]

Here’s the latest on the 1948 Cub. All fluids changed, magneto turned 360 degrees to get distributor 180 degrees in and re-timed. Changed metal inline fuel filter to a see through fuel filter and adjusted carburetor. Filled with premium no-alcohol fuel with a good dose of Sea Foam and Mystery Oil witches brew. Running great and the engine dying at idle went away. Decided to work her pretty hard today by pulling 5’X10’ utility trailer filled with hickory wood ( 3 loads ) from my closest neighbors house (1/4 mile). The road is a slight uphill pull from his house to mine and it worked the tractor pretty good. Pulled in third gear without any hesitation. I think I’m done with the engine. Now I have a question about brakes. My brakes are really weak. Going up and down my hills they barely stop the tractor without a load, with a load it’s really bad. At first I thought they may be a little rusty from sitting so long because they would chatter when applied. But after working the tractor they did not get any better, maybe even worse. Anyone have suggestions about tackling this problem?

[Dale Finch]

First check the pedal/rod-length adjjstment in the manual...Service Manual, I think.

Next, look from the rear of the tractor through the hole in the final at the break bands and see if they are centered over the brake drum. It is hard to tell if they ARE in place, but if the set screw has allowed tbem to migrate left or right, it will probably be obvious.

If both those things are OK, you will probably have to pull the finals to access the brakes. They could either be worn or could just have oil on them from leaking final or differential seals. Once you pull the brakes, if there is plenty of brake material all around, but they are oily, you can use a prolane torch to set them on fire and burn the oil off. If you are pulling the finals for the first time in a long time, go ahead and replace those seals in the finals and the differential...they are easy while its apart and are available at NAPA.

NOTE: I am sure you are aware, but a reminder to block the front axle any time you are jacking up the rear end, especially when removing the rear wheels with all that weight. There are several posts about brake and final work. GOOD LUCK!

[Don McCombs]

You should be able to see into the opening on the final where the brake rods come out. You may have to clean years of accumulated dirt and debris out in order to do this. See if you can tell if you have any lining left on the shoes. If you do, try adjusting the clevis on the rods to get more braking action. Be advised, though, that Cub brakes were never very good. Even straight from the factory.

[Dale Finch]

Here is a post done a while back...maybe it will help. Again, good luck!
http://www.farmallcub.com/phpBB2/viewtopic.php?f=1&t=78421

There is a part 2, but using my phone, linking is difficult!

[Smokeycub]

As Don said you can see what's going on visually and chances are the brake band linings are worn away. While there may be some lining still there, they could be glazed with rust/grease/dirt. Either way if adjusting the peddles doesn't help then a tear down will be in order. Here's a link to Rudi's manuals listed above, a great resource. Thanks Rudi and all those involved in that process. http://www.cleancomputes.com/Cub/Blue%2 ... Brakes.htm