I have a 1969 MF industrial 20 with a Perkins AG3-152 gasoline engine for which I have had for years. Lately, the tractor runs great for about 30 minutes to an hour or so of continuous use, then it starts to die. It seems to run somewhat if I use the choke but will die if the choke is not used. If I use the choke for a few minutes then stop using the choke it will run fine for a little while and then the problem repeats. Also, if I stop and let it sit for about an hour or so, the problem goes away until again, 30 minutes or so later of use. I replaced the coil, and check the fuel lines and the filter at the carb. Nothing found. Still have problem. Any other suggestions? Thanks.
Jim
Jim