I would make a " fuel log" that has "flow through", instead of it being at the end of the line on the way to the carb. It's eeeeezy enough to make your own out of braided stainless line.

You'll need 2 3/8" inverted flare to #6 AN adapters (the flare size is often specified by the threads, which for that size, is 5/8"-18), OR, instead of using the existing carb/flare adapters, #6AN adapters that go straight into the carb; 2 #6 AN tees; 6 #6 AN hose ends; acoupla feet of #6 hose; and 2 #6AN -> whatever fittings at the "input" and "output" of the "log". Hose barbs if you stick with the rubber hose and clamps, which if it was mine, I sure wouldn't; I'd make those AN as well, but that's another matter entirely. Start out with just the log, you can always upgrade the rest later.

Personally I like to use PTFE hose for this. Not only because it is FAR AND AWAY the eeeeeeeziest braided stainless to work with, but also, because its permeability is FAR less than the standard rubber lining of whatever sort it is. (not sure... nitrile? buna? EPDM? iunno…) The Summit brand line works just fine, and I like to use their black fittings. (not a fan of the red & blue although I use them when I have to) If you've never worked with that type of line, you'll need to do a bit of learning, but it's not hard. Use acoupla wraps of electrical tape over the cut, a wizz-wheel as the cutter, then take a razor blade to the inside of the PTFE liner and chamfer the inner edge just very slightly; a drop of oil on the nut threads, no oil on the inner; put the hose end in a vise with wood or brass or something to protect it, to push the hose on; and box-end wrenches to tighten the nut with, where possible, otherwise tubing wrenches, to avoid scratching the coating or anodizing. The nuts don't have to be very tight, 10 - 12 ft-lbs is ENTIRELY enough. I'd suggest, for a fuel log, make the 2 short pieces from the tees to the adapters first (very short piece of hose w/ the 2 ends onto it); install the adapters to the carb, and the short pieces to those; the center leg of the tees to those; put the fittings for the "log" piece on the inside of the tees where they face each other; then cut the "log" hose to about 1/16" longer than the exact distance that it needs to be.

Connect the fuel pump output after the filter to one end of the log, the regulator input to the other end, and the regulator output to the tank. Similar to NoEmissions' drawing except slightly different. Basically, the EXACT same plumbing arrangement that most EFI systems with regulators at the engine use. That way, the fuel in the log is kept constantly circulating, instead of it sitting still in there and only flowing as fast as the carb consumes it. Adjust the regulator to whatever pressure you like, IMO 4 - 6 psi is perfectly fine, since that's all a regular mech pump would provide anyway, and that's what a carb is meant to work with.

You should be able to make the whole thing for maybe $75 or so. I think you'll see when you put it up on there, why you don't want the rubber hose crap anymore... it'll look like the Mona Lisa next to the carb, and a 1st grader's scribbles on either side. In addition to the rubber crap being a serious fire hazard.

 

Back at it again years later. If you don’t mind you mentioned your idle needing to be 12:4:1 for this it to happen. Can you tell me What did you use to measure the air fuel ratio and does it hook into the carb to measure it?

 

Measuring AFR, to the extent that it's even meaningful, requires a wideband O2 sensor in the exhaust; subject to the caveat that an O2 sensor measures OXYGEN and infers AFR indirectly, not AFR directly, and therefore can be fooled by many things. Most notably misfiring.

 

I have a wideband installed, it's not a cheap tool but very handy when tuning a carburetor.
After setting the AFR to +-12.5:1 hard hot starts never happened again, another thing that had some influence in it was the 180 thermostat, my engine didn't like it at all, when the colder weather came in I swaped it with the 190 and it ran so much better never went back to the 180.