Fuel problem?

[Jim in SC]

Well, I was getting ready for a few days away, so I thought I'd start my '51 Cub and let it run for a bit (keeping the oil pump primed, etc.). Well. It started fine, but died when I took it out of the barn. It wouldn't start again, and eventually ran the battery down. The gas was fresh and I'm getting spark. I disconnected the gas line and the gas ran, but not terribly fast, so I'm thinking it might be a blockage (dirt) in the fuel line. Any thoughts? Oh - I got it back in the barn by towing it behind my newly acquired '69 Cub Cadet 106! That thing is a hoss!

Jim

[ricky racer]

The obvious place to start is by draining the fuel tank, removing the sediment bowl, giving it a through cleaning and flushing the tank out. I would also pull the main jet and check it for any obstructions. Once you've established good fuel flow to the carb, try it again.

[Eugene]

Start at the carburetor by removing the main jet from the carburetor. Check the fuel flow and for any blockage in the jet.

The work back towards the fuel tank looking for the blockage.

If it were only a partial blockage in the fuel line leading to the carburetor, the carburetor would fill after the tractor sat for a few minutes. The tractor would then start and run until the carburetor ran out of fuel.

It doesn't take much of a fuel flow to keep the carburetor full. Tractor burns about 1 gallon per hour with the tractor under load.

[Jim in SC]

Eugene, it did start and then die after sitting for a few minutes. It did that several times. I think both you and Ricky have hit it on the head. I'll be flushing out the fuel system when I get back in town. Thanks to both of you for the help. I'll post again when I get 'er fixed!

Jim

[Lt.Mike]

The brass elbow connecting the fuel line to the carb has a small screen attached which is hidden when its screwed into the carb.

My cub ran weak and would die when a load was put on it. It behaved very much like what you have described.
I checked the filter under the tank and sprayed out the main jet. All that could have caused the problem but didn't help.
It was frustrating until I discovered that little screen and then confirmed it was also packed with paint chips from the tank.
I sprayed it clean and the result was dramatic. Perhaps yours is a similar issue?
Mike.

[John *.?-!.* cub owner]

Lt. Mikes fuel screen appears to be the one used on a Zenith carb., If I remember correctly, the screen on an IH carb is a little cupped screen where the line screws in

[Jim in SC]

Thanks Mike and John. I'll be getting into the fuel line this week. While I don't think my filter screen is like yours, Mike, I suspect it has the same kind of "junk" in the line!

Jim

[Eugene]

The IH carburetor as John states, has or is suppose to have a screen in the carburetor inlet.

Disconnect the fuel line from the carburetor. Then check the fuel flow. If fuel flow is fine, then you will need to remove and clean the carburetor

[offrink]

Just for giggles try running it with the fuel cap off. Rare chance it could have a vapor lock. Easiest place to start and probably the least likely thing to be wrong, but I like to start with the easy stuff.

[Jim in SC]

Thanks again to everyone for the sage advice! I drained the tank and removed the stock fuel line and fuel strainer. The glass bowl had maybe a 1/4" of sludge and paint chips in it. The screen was doing its job (it was new when I restored the tractor a few months ago). The fuel line was running clear. The inlet to the strainer from the gas tank and the shut off valve were a different story. Clogged almost shut with sludge. Cleaned all that up and now I have to inspect the tank itself, hoping its not TOO dirty! Probably is though.

I'm thinking about replacing the stock metal fuel line and strainer assembly with a flexible fuel line, shut off valve, and in-line filter. I know, its not "stock", but is a lot easier to clean out, plus the fuel valve is much easier to get to.

Does anyone know the size fuel line to buy? 3/8" sounds right to me, but I would like some advice.

Jim

[staninlowerAL]

One objection to the flex line and filter is the greater possibility of a leak around the hot manifold which if happens might result in a fire. There are several threads on the "HOW TO FORUM" that deal with filters and fuel delivery system. You might pick up some ideas from others who have BTDT. I personally like the "in the tank" approach, using the upper neck of the fuel shutoff valve to anchor the filter (picture attached). Using a shop extension magnet, you can install it through the top opening. (Everything will have to be drained and dry to avoid colapsing the filter.) Unless your system is really bad, a good tank cleaning and the filter screen and sediment bowl will do a good job. OEM fuel line is 5/16 tubing, same as automotive brake line (steel is best). Carb inlet and shutoff valve outlet is 1/2 X 20 bolt threads. Don't use any type pipe thread fittings, they are tapered, the wrong thread size and count and will damage the soft metal on the carb and shutoff valve. The best fix for one that is damaged is helicoil. Stan

[Eugene]

Does anyone know the size fuel line to buy? 3/8" sounds right to me, but I would like some advice.

I'm using plumbing fittings with 1/4" hose barb.

[danovercash]

Check Stan's post above! Plumbing threads are different, don't ask how I know this. Also this is a gravity system, inline filters can cause flow problems. You probably don't need to fix a problem you don't have. Just clean system and go.

[staninlowerAL]

Does anyone know the size fuel line to buy? 3/8" sounds right to me, but I would like some advice.

I'm using plumbing fittings with 1/4" hose barb.

If you want to use plumbing fittings you can use a brass 5/16 compression union and rethread one side of it with a 1/2 x 20 bolt die nut to fab a male threaded fitting that will thread into the carb and shutoff valve. The brass is soft enough to thread easily, then you can use compression fittings to make other connections. Stan

[Jim in SC]

Okay, great responses and advice from all. Much appreciated. After draining and drying the inside of the tank, I checked it out with a flashlight and its not so bad. a rust spot or two, but really looks pretty good. After reading all of your posts, Danovercash's resonated with me - it may be a problem I don't have. Also, the comment about in-line filters and gravity flow fuel hit home. I'm just going to clean up the sediment bowl real good and clean out the tank real good, fill it with non-ethanol gas, and get to some fall plowing.

Thanks again to all who responded! This forum is such a great resource!

Jim