Farmall Cub

On my farmall 100 it tends to surge under load. When I surge I mean it will run fine for 30 seconds then kind of dies out then full power runns good repeat. Just driving around the property it is fine but put a disk behind or going up hill in the woods pulling a trailer full of fire wood it losses stride and sometimes up the hill wont pick up and quits and let me tell you full trailer up a hill and it stalls can be scary. I thought I had it fixed after I put new plugs in it but after a while started doing it again or more often. I am not sure if it is fuel starvation or an intermediate electrical problem does anyone have any suggestions?
Chad

fuel

Do you think its at the Carb?
I guess I will check the sediment bulb and make sure it is getting good gas there and the screen isn't plugged if that is good then should I pull the carb plug and see if it is getting good gas there? I am sure I did that and it seemed to be a good steady stream.
am I on the right track and if those are good what should I check then?

Start at the tank and work your way down. Could be dirt in the tank covering the outlet.

Sounds to me like you are describing a governor surging problem. Go through linkage checks etc, same as has been described for a surging Cub. The bumper spring is in the bottom of the governor, under the acorn nut.

A common problem on these is the screen in the inlet on the carb. It will fill with rust from the tank and cause fuel starvation under load. The screen is soldered to the elbow where the fuel line enter the carb. You will have to back the elbow out to get at it.

Daniel

A partially-clogged high speed jet will cause such symptoms. As the engine speeds up beyond the ability of the jet to supply enough fuel, the fuel mix becomes too lean and the plugs will not fire it in the cylinder. Thus the engine stops firing just as if the ignition had been shut off. As the engine slows, at some point the air-fuel mixture again becomes suitable for spark ignition. Since the throttle butterfly is open, the engine accelerates quickly until the fuel mix again becomes too lean.
As already pointed out by others, these symptoms may have multiple causes.

I will try out the main jet and the screnn inlet on the carb. Thanks
Chad

What kind of fuel line do you have
I had the same problem with our BN line was sagging lower than the carb, sounds like a good cleaning is in order. had a rubber line changed to steel.
Ours also had an in line fuel filter which I removed . Problem solved.
Phil

well I took the sediment bulb off and there was no screen so that wasn't it. Then I took the line off the carb and turned gas on and it gets a ton of gas. I pulled the carb screen out and it seem cleaned but I blew backwards on it and it seemed liked something woshed out. I get lots of gas with the screen hooked up. I ran the tractor with the fast hitch 5' disk. It seemed to be lots better but I had a few times it acted up but not like before. Maybe I need to pull the carb and soak the jets.
THanks for the help.
Chad