42 special issue

[Adam08ski]

This is perplexing me. My newly rebuilt 42 special is starting fine, idles well. Revs well and then suddenly leans out bogs and stalls if I don't feather if back to idle. I've replaced the tank vent and regardless I've ran it on the side with the cap off with the same issue. Tank is debri clean. Impulse is good, seals are good, metering lever set to the height of the body and needles set to 1 1/2 as per the service manual. To me it's as if it revs up, and then starves of fuel. Could the hose be collapsing at WOT? Poor coil at WOT? Or does the carb need a complete overhaul? The gaskets and diaphragms are better than some carbs that I have used that work fine. Help needed!

Cheers in advance guys!

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[Derf]

Sounds like as heat soak sets in a vacuum leak opens up. I’d check the boot between the carb and the cylinder, make sure carb bolts are tight.

 

[Adam08ski]

I can't seem to find any loose bolts on either the carb set up to cylinder or the cylinder to case. Hmm. I agree that something might be opening up causing vacuum condition but I just can't find it

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