i want to know EVERYTHING there is to know abuot how vaccum secondaries work. how to check them, test them, checking the floats, amount of RPM needed to open, everything.
my four barrell is not kicking in.
my four barrell is not kicking in.
DJCarbine said:How have you come to the conclusion that your secondaries are not kicking in?
Cobain03 said:you can go WOT untill about 4k rpms (engine dont rev high) and bring it back down and look at the vents inside the carb on the secondaries side and see that they are dry
Cobain03 said:might not be "proper" but if they have had fuel in them, then they should be wet, or at least a little slick.
This scenario would only happen if the secondary butterflys open but no fuel flows. If they don't open, no fuel flows and the engine's rpm will simply be limited to whatever the primary side will support. It will not lean out on the top end and cause any damage nor will it stall.BottleFed70 said:My question exactly.
Unless there is a mechanical obstruction keeping the secondary throttle plate from opening your engine would run very lean when you put your foor into it. It would bog badly and probably stall untill you back off on the pedal.
D.Hearne said:This scenario would only happen if the secondary butterflys open but no fuel flows. If they don't open, no fuel flows and the engine's rpm will simply be limited to whatever the primary side will support. It will not lean out on the top end and cause any damage nor will it stall.
They don't work that way. With the engine shut off and the throttle closed, the secondary butterflies are as well. They do not open after you shut the engine off. They as well will not open with the engine shut off and the primary butterflies pulled open. The secondary spring pushing on the diaphram keeps that from happening, they close by means of the linkage (drivers side of the carb) connecting the primary to the secondary throttle shafts. This link can also serve to convert the secondary opening to manual(or mechanical) by inserting a machine screw and nut into the slot that the secondary linkage rod operates thru, creating a sort of "poor-mans" mechanical secondary. But to make this work better, a larger 50 cc accellerator pump needs to be installed in the primary side to compensate for the temporary lack of sufficient fuel when the secondaries are opened ( which to those newbies out there is the reason for the secondary side pump on a "double pumper" Holley-type carb)BottleFed70 said:To check if the butterfly is opening, just look down the carb with the engine shut off. It should be wide open because there is no vacum with the engine off.
This is all you need to do to determine if the secondaries are working or not.
D.Hearne said:They don't work that way. With the engine shut off and the throttle closed, the secondary butterflies are as well. They do not open after you shut the engine off. They as well will not open with the engine shut off and the primary butterflies pulled open. The secondary spring pushing on the diaphram keeps that from happening, they close by means of the linkage (drivers side of the carb) connecting the primary to the secondary throttle shafts. This link can also serve to convert the secondary opening to manual(or mechanical) by inserting a machine screw and nut into the slot that the secondary linkage rod operates thru, creating a sort of "poor-mans" mechanical secondary. But to make this work better, a larger 50 cc accellerator pump needs to be installed in the primary side to compensate for the temporary lack of sufficient fuel when the secondaries are opened ( which to those newbies out there is the reason for the secondary side pump on a "double pumper" Holley-type carb)
Cobain03 said:engine off, the butterflies are closed. i have pushed them open before while the car running and it sucked air like crazy and no fuel came out.