Farmall 240 - Engine stumbles after 30 +/- minutes

Walter60 Farmall · Jul 29, 2014

Help. I have replaced coil, points,condenser,rotor,cap,wires and plugs. I have rebuilt the carburetor. I have pulled the head, pistons and sleeves. New pistons,rings,sleeves and had the head done with new valves.It starts easy and runs perfect until.....Thermostat works. Gas is good. Air filter clean. Coil is wired direct from battery with switch to eliminate old wiring issues. I have had and used this tractor for years.Need advice. Thanks

Janicholson · Jul 29, 2014

Feel the coil when it stumbles. If it is way hot, the issue might be that it is a 12v coil for use with a ballast resistor (which means it is really a 6v coil). If given 12v it can heat and break dowm, causing misfire.
If the coil is warm and not way hot, My guess is fuel related. Put a can under the carb, and drain fuel for at least 2 minutes. If the flow slows down you could be having a blockage at the tank to sediment bowl connection, r in the screen at the carb fitting. The fuel cap has one or two vent holes in the top. Make sure the vents are open. Jim

Walter60 Farmall · Jul 31, 2014

The coil is never hot. Coil is marked 6 volt no external resistor. Good flow from bowl drain. I ran the tractor with the cap loose. Nothing changed.

Janicholson · Aug 1, 2014

Drain gas out of the bowl for at least 2 minutes into a clean can. It is necessary to let the needle and seat have full flow. If it slows down, the Flow is restricted at some point.
One other possible issue is a intake manifold that is cracked or loose on the head and when it gets warm, it pulls away and lets in air. this can be checked with a unlit propane torch used to add fuel to the manifold area and listen for engine smoothing. (must be done when it is stumbling). Jim

Farmall 240 - Engine stumbles after 30 +/- minutes

Walter60 Farmall

New User

Janicholson

Well-known Member

Walter60 Farmall

New User

Janicholson

Well-known Member

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