Hey everybody- I've got a '66 convertible that I dropped a 331 stroker motor I recently built into. Everything is new, including the 80gph Holley mechanical fuel pump and the Holley 650 mechanical secondaries double pumper carb. Primaries are jetted down 2 sizes because I live in Denver, Colorado.
Issue: when I originally installed this engine and got it running, it ran fine unless I let it sit and idle for over 5 minutes- at which point the primary fuel bowls would both drain themselves dry & the engine would die. initially thought I ran out of gas & the fuel gauge was off, but after adding gasoline and finding that that didn't work I ended up literally dumping fuel down the carb until it would suck fuel back into the bowls again and run. I built this engine as a bucket list project with my dad back in Wisconsin, then drove it back to Colorado and had no problems with it during that 2000 mile trip because I made sure not to let it sit and idle for 5 minutes anywhere- in fact, it ran excellent! since then it has gradually progressed until now it runs fine until it gets hot (10 to 15 minutes) and then the fuel bowls completely go try again. This carb had no choke so I literally have to put a towel over the venturi and crank the crap out of the motor to get fuel to pull back through. I am at a complete loss as are all my mechanic friends as to why this is. I know the fuel pump works fine because I disconnected the fuel line from the carb and cranked it into a bucket -excellent and consistent flow. which also means no problems with the fuel tank, sending unit pick up or clogs. I tried running it without the gas cap on to make sure there isn't a venting issue-no improvement. So everything from tank to carb checks out. When trying to set float levels in the bowls, I could not get consistency. Anybody?..
Issue: when I originally installed this engine and got it running, it ran fine unless I let it sit and idle for over 5 minutes- at which point the primary fuel bowls would both drain themselves dry & the engine would die. initially thought I ran out of gas & the fuel gauge was off, but after adding gasoline and finding that that didn't work I ended up literally dumping fuel down the carb until it would suck fuel back into the bowls again and run. I built this engine as a bucket list project with my dad back in Wisconsin, then drove it back to Colorado and had no problems with it during that 2000 mile trip because I made sure not to let it sit and idle for 5 minutes anywhere- in fact, it ran excellent! since then it has gradually progressed until now it runs fine until it gets hot (10 to 15 minutes) and then the fuel bowls completely go try again. This carb had no choke so I literally have to put a towel over the venturi and crank the crap out of the motor to get fuel to pull back through. I am at a complete loss as are all my mechanic friends as to why this is. I know the fuel pump works fine because I disconnected the fuel line from the carb and cranked it into a bucket -excellent and consistent flow. which also means no problems with the fuel tank, sending unit pick up or clogs. I tried running it without the gas cap on to make sure there isn't a venting issue-no improvement. So everything from tank to carb checks out. When trying to set float levels in the bowls, I could not get consistency. Anybody?..