belarus 310

Any commonly seen problems with the pto suddenly stoping mid mowing?

some friends of mine just bought a 310 and it will not get fuel to the cylinders. is there a cut off on the pump or are they going to have to rebuild the pump? the tractor set up for about 3 years an di know they need to buy two, but they did not and we need to get this one running

Anyone have any experience with one of these or a sibling?