2100 series is an excellent carburetor design. The throttle shaft bores are prone to wearing in the castings after high mileage. Cause vacuum leaks. Check for this. Other than that... Arguably the best carburetor ever made, excellent fuel atomization with their annular discharge clusters. Not quite EFI though close. They are easy to work with.

First thing to check when setting up any carburetor is the fuel pump. Recent manufacture fuel pumps esp. imports, are notorious for being waaaay out spec for psi, on the high side and/or erratic. This is a critical setting to check because everything else that follows carburetion wise is based on the correct fuel pressure being maintained at all times under all conditions. Something like 3 to 5 psi. Don't guess, have to measure.

The dry float height spec listed in the instruction sheet or manual is a bench setting, just to get in the ballpark. The fuel height in the bowl is what counts and needs to be checked. Adjust the wet float height up or down after installation as required to achieve the correct fuel height in the bowl. Different carbs in different applications vary in the manual but 29/32" fuel height should work. As it happens this is the same diameter or near enough as a US $.25 coin or quarter, which makes for a handy gauge. Measure from the machined surface of the carb down to the surface of the fuel.

Look in the manual for the PV (economiser) for your altitude. It may be a 5.5" instead of a 6.5" or 7.5". That's going to be the listing for a stock engine, and is just a starting point.

Keep in mind if you have a performance camshaft the manifold vacuum will run much lower on average than a stock setup. So the correct PV for your engine may be lower yet. The situation to be avoided is where the power valve remains open constantly or opens too early. The only time the PV or power enrichment circuit comes into play is under heavy load on acceleration. If it is sized too close to the average manifold vacuum it will be open when it should not. Say, a slight headwind on the highway. Then you can watch the fuel gauge needle go down in real time.

This mismatch also makes correct cruise jetting impossible, and of course fuel economy falls off a cliff. Oil dilution and plug fouling etc. This is another situation where a mechanic's vacuum gauge is useful so the mechanic can see where his particular engine operates at steady highway cruise and acceleration, deceleration, and slight grades, elevation, camshaft etc. Then a power valve size can be selected that will work. Yes all this testing can be a pain in the *** to setup but do it once, do it right, you'll be glad you did. The alternative is to pay somebody else to do what they think will work. Good luck with that!

I read a forum posting somewhere, this one guy somehow got it in his head that float height adjustment had to be done on the 2100 with the engine running. His adventure was at night with a flashlight on the side of the road. Yeesh.

it goes without saying any kind of carburetor or fuel system work/maintenance should always be done with a full size fire extinguisher ready and available. I also carry a medium size extinguisher mounted in the truck. There's enough "tales of woe" here at this site and elsewhere, and some really sad YT videos, to make me a believer.

If one is VERY careful, it is possible to observe the engine idle with the air horn removed. It isn't really necessary though, the procedure spelled out is to let the motor idle for a few minutes on level ground. Engine fully warmed up. Shut it off then remove the top. Check the fuel height level in the bowl and adjust float, if required. Careful not to jam the viton needle tip into the seat when bending the tab. The fuel height in the bowl is also a critical adjustment, because it sets the baseline for how much fuel is drawn through the idle air and high speed bleed orifices &c. If it's too low it will be starved for fuel at high speed, and too high it may flood or run rich. Then the out of spec condition will lead to the tuner to add in compensation errors in jetting and elsewhere.

I wouldn't be worried so much about the distributor, esp. with the fan running, it would mitigate the fumes.

What would be far more likely though from a safety standpoint is the fuel pump w/ high pressure blasting a spray far and wide past the inlet needle and seat onto the hot exhaust manifold.

I tried it once just to see the fuel level at idle, and I found the fuel pretty much dribbles past the needle seat with pretty good pressure, (thankfully into the bowl, not across the engine bay) almost constantly.

I had thought it probably worked similar to a toilet tank and float, and would take maybe 30 seconds or more, before the needle & seat allowed more fuel in. Doesn't work that way. Had to drop the float quite a ways to get the fuel level in spec. Probably the fuel pump I'm using is a little on the high side pressure wise. Need to take my own advice and check that. Somebody on one of the auto forums said they picked up an extra mpg or so just by reducing the fuel pressure at the carburetor to dead nuts on spec.