stromberg cd150 running rich

[spittyholly]

my gt6 is running rich at 9% co it has stromburg cd150s which you adjust needles down the dashpots I removed the carbs and set the float levels to 18mm as in the big red book checked again and still the same I set the needles delving washer flush with the pistons still at 8% co when I weakened the needles anticlockwise 1 turn.the exhaust note is chuffing.while on the machine I pulled the pipe off the rocker box that feeds the two pipes to the carbs and it purred like a cat co2.5% hydrocarbons 360. sweet I changed the oil today to see if poss fuel contamination in oil.its better but still runs better with the pipes to the carbs going to atmosphere..when I put my finger over the pipe going to the carbs the idle dropped and co went back to 8% so I guess these carbs need the air to feed to the carbs via these pipes. could I put the pipe off the rocker cover into a breather bottle and put one of them breather filters onto the pipes feeding the carbs or would I be better of blocking the pipes to the carbs and trying to set it up cheers I did read somebody done it with their vitesse but cant remember wear I see it has anyone done it :-/

[rotoflex]

I have seen many versions of running the rocker cover pipe to a catch can, & then blocking off the pipes at the carbs (at least one way was to just run a hose from the pipe on one carb to the other).

I really can't remember where the vacuum on the carbs for the rocker cover goes inside the carbs, but I think you do need to block them off if you're running to a catch can.

[Pete Lewis]

if you have the temperature compensators fitted on the sides check the two sealing rings and that the valve
is closed, if the thing is not 'just' seated turn the small nut till it closes the plastic needle and shuts off the air bleed bypass to the throttle plates,  if its ope all the time at cold and normal running you wont set the mixture  correctly


Pete