fugly
Well-Known Member
I will repeat this one more time- I DO NOT KNOW WHAT THEY WERE SET UP FOR OR WHAT YOUR ENGINE SPECS ARE. This makes it near impossible to tell you definitively what to do. I have alot of info on the white paper mentioned above as well as three or four more carb papers at the same site. Some basic stuff I see wrong tho- one is the perception that the doors are opening too slow- if you are launching at 2800, the doors will not be open and if they open too fast, that will cause a bog not the other way around. There is no accelerator pump shot on the secondaries, therefore if they open too fast, you WILL go lean. The last thing you want to do is start with all the weights out. The quicker the door opens without a bog, the better the 60', but I would start with one screw in each side.( some people completely remove the doors and have no ill effects on launch-I do NOT recommend this unless it is a large high revving engine- if you do not move enough air, you risk an extreme lean spike this way, and the doors also help to form the venturi and affect the midrange curve) Also the jetting and rods you put in are likely too rich ( don't even know CID on yours so this is an educated guess). Just to put things to bed one last time I hope, there are numerous internal mods ( these have to do with internal circuits and calibration) -I am not going to reveal info on that, but there are over 70 possible mods on the auto carbs and 74 on the ones for manual. Many are to help the curve, but some that apply to both are specifically to deal with bogging and high end lean out (same mods affect both)This is one of the primary reasons I build them car specific and the main reason trying to get a used set calibrated can be difficult......all that said, the carbs will tune well enough not to bog, I just don't know how well they will do compared to a proper set (could be the right set for yours, I just don't know) Like I said before , most are designed for stock jetting- if you are too rich or too heavy on the springs what happens is there is nothing left to add when you launch (load) the engine. If you are to light on the springs, they will never open- the carb paper explains how to test those so I won't repeat it here. I would go back to 7147 rods at a minimum and I will guess it may want blue springs ( PLEASE READ THE PAPER AND CHECK THEM) you want the metering rods lean at staging and immediately to rich on launch- if they do not do this, it will bog and usually this is the reason when they do. If you did not crank the pressure up, this could also cause it. the floats should be set at .380" , not the stock setting. Normally, the launch is covered by the primaries well past the bogging area, so I would concentrate tuning efforts there to start with. Also, the mixture screws and idle speed setting are critical, ESPECIALLY the speed setting- if the primaries are too far open, it WILL bog- how much of the transfer slot is exposed? How many turns out are the mixture screws? These settings are also major clues to what is going on. How big is the engine, what's the cam specs, how hard are you turning it?
