1951 B surging after rebuild

1) First, try removing the throttle rod from the governor and see if when you manually throttle her it will idle smoother and NOT SURGE??? If it will run smooth then at all RPM's and not surge, you may have a governor or linkage problem. The last rod to the carbs top should be set to where at open throttle on the hand throttle and wide open on the carb, the rod should be about 1/2 hole short of dropping in.

2) Next, a vacuum leak can cause poor idle and surging. At idle, spray WD 40 or Carb Cleaner or an unlit propane torch around the carbs mount and its throttle shaft bushings and the manifold base etc and if she speeds up n smoothes down someplace, you found a vacuum leak.

3) If manually throttling dont help, and you dont find any vacuum leaks, especially at the carbs throttle shaft bushings, and adjusting the carbs top needles dont help, you could have an internal clogged idle circuit in the carb.

4) Fixing that usually requires heat to remove the brass drill plugs over the idle circuit passages. See

Link

~You will also have to pull the load nozzle & clean it's air emulsion side holes as those holes plug up with dirt & rust..

***************** Removing The Load Nozzle**********************

~ To do that just remove the carbs float bowl [be real careful removing the bottom bowl nut as the carb stem breaks easily & watch you don't lose the nozzle retaining spring],, then you will probably have to at least tap threads in the bottom of the nozzle.. DON'T drill it first, just find a tap that will fit the hole & use that..

~Try to find a standard size tap so you can use a long bolt or piece of all-thread rod that will fit the tapped hole.. Don't run the tap in any farther than about 1/4" on those DLTX carb's.. You don't want to tap in so far that you effect the bottom metering holes that are drilled in the side of the nozzle..

~Once the load nozzle has threads tapped in it's bottom just use a long piece of all-thread threaded rod with a stack of washers with a nut on the bottom.. Screw the all-thread in the bottom of the load nozzle, then install the washers & nut & when the nut is tightened the nozzle will pull out .. DO NOT pry on the top of the nozzle to help it out as any damage there could severely effect carb metering.

~Once the nozzle is removed clean the air emulsion holes that are in the side of it..

~Then you should clean the bowl vent in the top of the main casting inside the top of the float bowl area as a plugged bowl vent can also effect the metering & carb's operation..

~There are a few other areas that need cleaning & attention so I sent you a carb cleaning diagram [check your E-Mail]..

~On the throttle holding position?? You probably either have a broken spring [look closely at that spring as a break is hard to see] , or the seat is worn. Try cleaning of some of the lube with brake clean & if that doesn't help add a stronger spring or a couple of washers to increase the spring preload..

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