Dual Carbs, Idle Options

[cpavlenko]

Starts right up with good idle, but after a good drive when stopping for red light, it wants to start dying and drops idle real low. Like 500 or less rpm. My idle on the Weber 40's when cold is about 1200 rpm and and smooth. Any thoughts out there. 1.7 built to a 2.2. Engine has almost 600 miles since build. Other than this problem, it runs great. Oh oil temp after good run bout 210 to 220 degrees in 95 degree weather.

[michael7810]

Couple thoughts. The linkage shouldn’t be an issue if both stop screws are set properly. Even if the cross bar is affected by heat the throttle plates can’t close if the screws are set. Is the idle mixture set while hot? Maybe try setting the mixture screws after a run when the idle is low. Are the carbs synced? Is the centrifugal advance sticking when cold and retarding too much when hot (check timing at idle cold and see if it changes when hot). Are you using vacuum advance, if so make sure it isn’t advancing the timing at idle (check hot and cold). As said above it could be the float setting.

[Mark Henry]

Couple thoughts. The linkage shouldn’t be an issue if both stop screws are set properly. Even if the cross bar is affected by heat the throttle plates can’t close if the screws are set.

Wrong.