Mercury Monarch carb problem?

I’ve got a 1977 Mercury Monarch with 144k and a 302 V8. When cold it starts immediately but often is difficult to start when warm. The engine runs great with plenty of power but sometimes stops on a curve or while waiting for a light. I’m also only getting 10 mpg. Is this a carburetor problem? I don’t see the model listed so I clicked on Grand Marquis.

1 Like

Everything you describe as a problem is pretty much what ALL drivers of these cars lived with every day!

The car was never made to run on gasoline with 10% ethanol (alcohol) added. The ethanol degrades EVERYthing in the fuel system over time. Fuel pump, lines, and carburetor. It also reduces mpg’s overall and can be much worse on cars set up for non-alcohol fuel. If you continue to drive this car, replacing the fuel lines with ones better suited to modern gas is in order.

I’d also guess the carb does need a rebuild sine the ethanol destroys the rubber parts inside the carb.

Given that these cars didn’t get a whole bunch more than 10 mpg (city driving) back in the day and will get less with modern fuel, don’t expect miracles with a carb rebuild!