FUEL SYSTEM

Open the fuel valve two full turns for normal operation, and all the way out to get the remaining one-gallon reserve.

It's a good idea to close the fuel valve completely when you shut the tractor off for the day. It's a gravity-feed system, and the tank is above the engine, so if the float in the carb does not seal, all of that fuel could end up in your engine. Especially if it has a couple of days to drain.

The Ford 8N Tractor fuel system has three (3) screens. All three of those screens need to be clean for proper fuel flow. A good way to test the system is to put a can under the carb, remove the large plug at the bottom of the carb, and then open the fuel valve on the tank. You should get a good steady stream of fuel after the carb drains. If the flow of fuel slows down significantly after what is in the carb is gone, start looking for the problem.

One screen is in the tank. You have to completly drain the fuel and remove the fuel shutoff valve assembly to clean that one. Don't forget to also drain the reserve fuel supply by screwing the fuel shutoff knob all the way out. If you don't you will still have about a gallon of fuel in the tank when you remove the valve. Ask me how I figured that out. Before starting this repair it might be a good idea to have a replacement fuel valve assembly. The old one can probably be cleaned, but a replacement will have your tractor ready to go again much faster.

A second screen is located just above the glass sediment bowl at the bottom of the fuel shutoff valve. Loosten the bottom nut, remove the glass jar, and the screen is above the seal. Before removing the glass bowl, it is a good idea to have a replacement gasket and filter to put in there. It might not be a bad idea to have a replacement glass bowl in case the old one gets dropped on your concrete floor.

The third screen is attached to the fuel inlet elbow on the carb. Remove the fuel line and unscrew the brass elbow to get to that one. It is made right on the end of the brass elbow.

If any of the screens is clogged, look immediately upstream to find the source of the problem. Usually the problem will be a dirty or badly corroded tank. Flushing and cleaning the tank may help, but if the problem is corrosion, you need to fix it or get a new tank. There are several tank repair products available that coat and seal the inside of the tank and may fix the problem. Make sure the coating is suitable for ethanol fuel if you run pump gas with ethanol.

When replacing taper-threaded fittings don't forget to use sealant on the threads or they will leak. Don't use regular plumber's tape, use the sealant that is suitable for natural gas lines and fuel systems. It comes in a tape roll similar to regular plumber's tape, but it's usually yellow color and thicker than the teflon stuff. There are also brush-on products if you prefer.

The fuel line is a flare fitting, the threads on this tpe of fitting don't seal anything, so there is no need for sealant on the fuel line fittings. Just make sure both the pipe and the socket are clean.

Replace any lines or fittings that are corroded or if hex nuts are rounded-off.

Please, DO NOT use rubber hose, add inline filters, or use anything but plain steel tubing for the fuel line! Rubber hose next to a hot manifold becomes an instant fire hazard. The in-line fuel filters are generally too restrictive for a gravity fuel system. They may flow ok with a full tank but when there's only a gallon ot two left, there's a lot less weight pushing fuel through the screens. Adding anything else usually causes fuel feed issues.

I often see copper tubing substituted for steel. Obviously after replacing a rotten fuel line a previous owner decided to more permanently fix it. The problems with copper are a little more subtle.

The cheap, unprotected steel fuel line was used on purpose. The engineers knew that when dissimilar metals come in contact, and are exposed to weather, one will always become sacrificial and protect the other. Their intent was to make the least expensive and easiest to replace part the sacrificial part. That is why the fuel line was plain steel. When you use copper your gas tank becomes sacrificial! When we replace a rusty fuel line, all that ugly rust is rust that didn't form on or in the gas tank!

Copper tubing is also softer then steel, it will work harden and crack at the fittings which is of course a fire hazard. I mention fire because a little fuel leak plus sparks from an implement in the middle of a dry hay field occasionally leaves a tractor owner with a few very fast decisions to make before he becomes the weekend barbecue.

UNLEADED GASOLINE: Even though this is an antique engine, it is not necessary to add lead to the gas or use hi-test gas. The Ford tractor engine is a low compression (6.5:1), low hp (25-30 hp) industrial engine with hardend valve seats for long life. It will be perfectly happy and run best on regular low-test unleaded gas.

ETHANOL FUEL: I have not noticed any problems with ethanol-blended fuel other than reduced efficiency and perhaps slightly more corrosion in the fuel system. Those observations are opinion and not proven facts. Perhaps I should apply for a government grant to do a comprehensive study? Does 12 million sound about right?

DRAINING THE FUEL:If you let your tractor sit, mostly unused over the winter months, this is considered short-term storage. You should put some Sta-Bil or equivalent fuel conditioner in the fuel to keep it fresh. It is also a good idea to keep the tank nearly full of fuel at all times, unless you are completely draining it for long-term storage. This will help prevent moisture and rust from forming in the tank.

One recommendation passed down from our grandfathers is to drain the carb after each use. You turn off the fuel valve and let the engine suck all the fuel out of the fuel system until it dies. This practice may never have been a good idea for anything except long-term storage. With today's ethanol blended fuel the residue left in the system after each draining quickly dries and leaves deposits. Draining the system frequently will cause those deposits to quickly build up clogging filter screens and passages.

FUEL STABILIZERS: I have heard that the regular Sta-bil product was not intended for anything but gasoline. Using it on ethanol-bended fuel may be a problem. I don't know, but the marine supply stores do have a new Sta-Bil product that is intended for modern ethanol-blended pump gas. Perhaps, by the time you read this, all of the stabilizer products will have been reformulated. Please, Read the label!