hi just observation , the fully closed aspect is not critical ignore it on that end of it , still chokes if not closed , better open a bit anyway .. many ( better) carb set ups describe putting a certain size drill in there to hold choke NOT fully closed. when setting , that matches the sides too Dont look for more precision in this than it has . It is quite crude as has bern discussed . — in particular temp of choke coil and so position of choke cold is inherently erratic (“ bend the rod, “ ambient temp, calibration of rod / zero point at coil adjustment end at coil lever at 70F to temp as it warms etc ) .Rate it opens at … all variables clearly fast idle gotta work right , and fully closed end precision is just not required . But fast idle has to work What IS required and hard to get is they both pull off as best you can get it at same time, at same rate . That involves heat risers too Very much so . Maybe measure temp of carb base with IR gun on warmup — has to match during warmup or you get nowhere If one goes off high idle before other you get loping and stalls Another aspect ( here goes John, he cant resist ) is vacuum advance on these is manifold vacuum not ported (!!) must be only car like that on earth, you get full vacuum advance at idle (!) then goes away, (that slows motor rpm off idle if it drops (!) then it comes back at higher rpm . Dead wrong , why there is ported vacuum on every non ram car made , except some corvettes with 290 cam ( no vacuum there anyway) ( look up how ported works and why —if not familiar - great idea) Vacuum comes smoothly as you open carb , rpm rises port is exposed — it us on top of throttle plate no vacuum to speak of or low at idle . Co ordinated by design with idle screw typical opening . Designs vary , impacts mileage So per fsm you do all this with vac off , then redo to lower rpm ( I guess) when you reconnect . Trying to think — why this air valve ? ? I think they picked special carb with air valves , no idle screw on butterfly , to avoid interaction across throttle linkage setting idle by idle screws ? I mean why else? They depend on counting turns of air valve opening to natch sides but then you cannot have ported vacuum slots that work right , as idle air is bypassing throttle plates just off idle through the air valves. — on regular setup that flow at throttle edge in front of port is a critical part of ignition advance action below 2500 rpm Here , vacuum to the ignition just off idle charges little , maybe they fixed somewhat by special metering rods ? dont know. Do know it is not right , really I got into similar quandary , what IS fast idle RPM? you saw in F FSM ,I Quote ; “ There is no specification for fast idle RPM “ —- right Electric chokes really help as they are far more likely to track side to side , imho THE problem (as designed ) electric eliminate about ten erratic variables , only downside is eliminating the suffering purists love . Noel has noted how he does fine without erratic carb heat risers ( me too ) he has more miles by a factor of ten ( guess )than anyone in a ram 300 today — his chokes are / can be set to track no doubt ,consistent rate under hood warming , also set so so fast idle can be lived with . Much more stable , slower warmup is much less of an issue than flooding stalling , unequal pull off , overheated carbs due to stuck or unequal heat risers , melted ram floors etc To me ,— just don't want that , or risk of it Not driving a 300 in 2026 at 20 degrees either . YMMV PS Next build if I ever get there , AVS carbs ,,idle screws , make bell crank linkage adjustable at ends for that ,or Lokar pull cables , ported vacuum , electric choke , water heat in J plenum , no connection to exhaust manifold , Use “uni sync “ to balance carb air flow Someday .. in a blue F waiting for it .. On Jan 9, 2026, at 12:15 PM, John Nowosacki <jsnowosacki@xxxxxxxxx> wrote: -- For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang --- You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group. To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx. To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/20FC6920-306F-4AD4-A400-54BF781D6BE8%40gradyresearch.com. |
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