OK, what about the choke (electric, thermal, or manual?)... should likely be adjusted open if the ambient is above 95*. If not, wire it open temporarily.

Looking down the carb venturi (engine off & choke butterflies OPENED), are you getting a squirt of fuel from the accelerator pump when the main butterflies are thumbed open? If so, that squirt(s) should be enough to start on. If not, that's a problem...


For the "high idle", you need to confirm the butterflies are closing COMPLETELY once running.

- Is the throttle linkage holding it open? Pull it off and see...
- Have you checked/backed off the idle stop screw? (not the idle mixture screws) It's used to set the idle RPM & could be holding the throttle open.

*IF* the throttle butterflies are closing all the way, you have (at the least) a vacuum leak. (use extreme caution here!)Use some flammable carb cleaner or RRichs propane trick (harder to use without disconnecting the cooling fan as it blows around) to check for vacuum leaks around the manifold-to-adapter and the carb-to-adaptor areas. Some adaptors are uber prone to sealing issues due to the bolt spacing vs the carb flange and require additional sealant to seal completely.