Ford 860 stalling under load

[Jmunden]

Ford 860 is stalling under load. It’ll run fine for maybe 20-30 minutes while brushhogging and then it’ll start sputtering and stalling. We’ve tried changing points/condensor, cleaning oil bath and air intake. Only thing we can think of now is the carb needs cleaned

 

[Fordfarmer]

Ford 860 is stalling under load. It’ll run fine for maybe 20-30 minutes while brushhogging and then it’ll start sputtering and stalling. We’ve tried changing points/condensor, cleaning oil bath and air intake. Only thing we can think of now is the carb needs cleaned

Easy /cheap stuff first. Have you verified good flow to the carb when this happens? Could be clogged vent, causing a vacuum in the tank, junk floating in the tank, getting sucked up against the valve opening, partially clogged screens, etc

 

[showcrop]

Did you try opening the main jet just a little?

 

[Jim L WA]

Try a new coil.

 

[Btzj02]

Ford 860 is stalling under load. It’ll run fine for maybe 20-30 minutes while brushhogging and then it’ll start sputtering and stalling. We’ve tried changing points/condensor, cleaning oil bath and air intake. Only thing we can think of now is the carb needs cleaned

I agree with Fordfarmer, easy cheap stuff first. Take the time to verify if the stalling is due to loss of fuel or loss of spark and go from there. Check for spark right after it stalls. Does it restart immediately or does it have to rest for a while before you can restart? Conventional wisdom is if you are losing spark after 20 or 30 minutes it may be the coil but, if you do not lose the spark it may point to a lose of fuel TO the carburetor or THRU the carburetor.

 

[Jmunden]

Easy /cheap stuff first. Have you verified good flow to the carb when this happens? Could be clogged vent, causing a vacuum in the tank, junk floating in the tank, getting sucked up against the valve opening, partially clogged screens, etc

Took the sediment bowl off and it flows fine to it and the gas is clean in the bowl. This was the first thing we did and I forgot to put that in.

 

[Jmunden]

Did you try opening the main jet just a little?

Haven’t. Will give this a try. Thanks!

 

[Jmunden]

I agree with Fordfarmer, easy cheap stuff first. Take the time to verify if the stalling is due to loss of fuel or loss of spark and go from there. Check for spark right after it stalls. Does it restart immediately or does it have to rest for a while before you can restart? Conventional wisdom is if you are losing spark after 20 or 30 minutes it may be the coil but, if you do not lose the spark it may point to a lose of fuel TO the carburetor or THRU the carburetor.

It does start back up after stalling but will also start stuttering again and attempt to stall, unless I throttle it a bit, which will keep it going. So I’m really wondering if it’s something with the carb. Trust me I want to check all the easy and cheap stuff first haha

 

[Jmunden]

Try a new coil.

Appreciate the advice! I’ll look into this as well. Thank you!

 

[used red MN]

The elbow that the fuel line connects to on the carburetor has a fine screen that can plug, see 17 in linked parts diagram.
You need to test fuel flow out of the carb.
Here is the process to test if you are getting enough flow out of the carb drain. If you pull it out make sure that the area around it is cleaned up good with carb cleaner.
CNHI Ford 860 carb parts diagram
I suggest you test your fuel delivery to the carb. Get a pint jar, something that will measure a pint. Open the carb bowl drain and let it drain about 5 seconds. This lets the fuel that is held in the carb bowl drain so the test is not thrown off. Then begin catching the fuel for a timed 1min 45 sec. Should fill the pint measure in that minute and 45 sec. If it does not run enough fuel out of the carb drain to fill it recheck it at the line disconnected from the carb. Here you can immediately start the test on this line. If it has good flow there it is possible that the fitting that the fuel line connects that screws into the carb has a fine screen on it that can plug. Pull it out and check it. Some models have them and some don't. If the flow is not good enough out of the line you have to figure out where it is getting blocked. It may be the screen on the outlet to the sediment bowl in the tank. Take a good flashlight and look in the bottom of the tank to check for an abnormal amount of debris in the gas The 1 minute 45 seconds for a pint calculates to be 4:2 gph, this is a bit over what your tractor consumed when tested under full load. This will assure you have adequate fuel to operate the tractor under full load. You will probably never do this unless you participate in a plow day.

 

[paul]

Coil gets hot. We put an inch block of wood under it, with longer bolts.

Distributor shaft gets worn. Needs a rebuild.

Gas gets too hot. Move the muffler out from under the tank; change up the fuel line to keep it shielded/ away from heat.

Some random thoughts. If it runs pretty good when cool, but doesn’t when it gets worked hard and hot.

Paul

 

[rotozuk]

Been dealing with something similar on a different vehicle. I'm going to check for lack of venting on the fuel tank. Pretty sure that will be it, but I also have a cheap chinese fuel filter, that will be going to the bin.

 

[showcrop]

Having gas to the carb is nice but it is a whole lot better for it to be getting into the cylinders.