Some Bronco's I feel have a major design flaw. Look at the carb fuel line elevation and the level of the bottom of the tank. If the tank is no more than about 1 1/2" above carb inlet, they run fine till the spring type fuel inlet needle gets some hours on it and then fuel delivery problems ensue. Factory is "not aware" of issues when I asked, but I can tell you for sure that uphill will be a problem, and under load as when you engage the PTO will aggravate the issue. We fought a unit for a month, then discovered the stupid issue. It was 2 years old when the issue appeared, replacing the carb helped but will only have a return issue in my opinion.