Re: 1937 ford flathead won’t rev up
If definitely sounds like a fuel issue. It's time for a carb overhaul. Closing the choke to get it to run eliminates everything else. I worked with a guy that was the carburetor rebuilder at a Ford Dealer in the 1960s-1970s. He took a regular air blow gun that has the threaded safety nozzle to reduce pressure. Unscrewed it and replaced it with a brass adaptor that accepts a foot-long piece of the smallest brake tubing, 3/16". He blew-out every passage with that tool. Then he took a spray can of carb cleaner that has the red plastic straw nozzle and forced it against each passage to make sure it sprayed out the other end of. I never saw one of his carb rebuilds not work perfectly. He always put a little white grease on the base gasket so that if you had to remove the carb later on the gasket was reusable and you didn't need to scrape it off the intake. The other thing is to not gorilla tighten the screws and strip them or warp the pieces. Just snug them. Check the carb base and carb top to make sure its flat and the throttle-shaft for play, a tiny bit of play is okay. A lot of play will give you a vacuum leak at the shaft. If you know every passage is clear, the carburetors have no cracks. you replace everything that is not metal. the gasket mating surfaces are flat, throttle shaft play is okay, float level is set correctly it should run great when your done.
Air fuel adjustment is the fial adjustament that is done, First the points dwell, then the timing and lastly air-fuel-ratio. It must be done it this order. Adjust final air fuel mixture using a little camping propane bottle. Its not necessary but it works great. Gently bottom out the A/F screws, if you overtighten those precision needle and seats you can damage them. No matter what carburetor I'm working on I always back them out equally 1 1/2 turns. With the engine warmed up adjust the idle speed. Open the propane bottle a little and pass it over the top of the carb. If the idle goes up the mixture it too lean, If it goes down it's too rich. When you have the mixtures screws turned equally, adjusted close to where they need to be the rpm will not change with a "little" propane. Because atmospheric pressure, temperature and altitude vary while driving you want to set the idle mixture slightly to the rich side. Give the screws a n additional 1/8" to a 1/4" turns out and your air fuel mixture will be perfect. Anybody can do this. "Always", work outside when working with fuel systems so that if there is a fire (you forgot to tighten a clamp and a hose comes off,...) you don't burn your garage and house down. That also applies for starting engines for the first time.t is real easy to get distracted and leave something loose. Its good idea to double chek it before you start an engine.
