Hi,
I noticed that you mentioned the problem started after steep hills. The MF 135 has a large, flat fuel tank and the sloshing of fuel back and forth may have dislodged debris and blocked the fuel system. Check your ignition first, then consider the following:
1. There's a small filter in the tank directly over the outlet, or at least I believe there was from the factory. I hear talk of these blocking. Mine is missing so can't block, but it allows debris to get down the line.
2. The glass fuel bowl, if you have one, gives an idea of how much fine debris is coming from your tank. Check to see if there's plenty there. If so, consider that the carby might have debri in it.
3. Remove the fuel line from the attachment at the tank/sediment bowl. Turn the fuel tap on and expect a steady stream of fuel. If not, your issue is a blockage above that point. You'll need to remove the tap and investigate.
3. Check the line from the fuel bowl (or tank if there's no bowl) to the carby by removing and blowing it out. Try starting it again. If the problem persists, consider the following.
4. Debris often gets caught in the needle valve on these types of carbys. Checking this involves disassembly for most carbys, hence why you want to have checked the ignition system first. They're not unduly complex, but it depends on your level of skill and enthusiasm. The second point that debris often blocks a carby is the main jet and the idle jet.
I have found algae, paint flakes and a Phillips screwdriver causing issues by following these steps. Hope this helps.
