Qjet Float Height Looks Wrong

[Bonnewagon]

The check ball is there as a one-way valve. Gas can flow in for the accelerator pump but when the plunger pumps, gas goes out the spigots. The APT (Adjustable Part Throttle) was set at the Rochester factory by means of a big fancy analyzer/computer to pass emissions. But WE use it to tune for best performance. It raises and lowers the rods a bit for better take-off power. If you have an exhaust analyzer you are better than me. I just use the seat-o'-the-pants meter. Doug Roe's excellent book explains all this better than I can.

 

[Supercharged111]

The check ball is there as a one-way valve. Gas can flow in for the accelerator pump but when the plunger pumps, gas goes out the spigots. The APT (Adjustable Part Throttle) was set at the Rochester factory by means of a big fancy analyzer/computer to pass emissions. But WE use it to tune for best performance. It raises and lowers the rods a bit for better take-off power. If you have an exhaust analyzer you are better than me. I just use the seat-o'-the-pants meter. Doug Roe's excellent book explains all this better than I can.

My intent is to use the cheeks and, down the road, a wideband. It ran good before, response was nice and snappy, but it reeked and was always rich. Plus when I did a 1-2 1 wheel peel in front of my sister it left such a cloud I wasn't sure how much was tire smoke and how much was exhaust. That and the idle screws doing nothing have me wondering what was to blame there. Hopefully the dejetting for altitude does the trick, but I suspect all the notes I'm taking will come into play once I try tuning this thing again.

 

[Supercharged111]

The APT is also a Double D just like the idle screws. So the 1/4" DD socket fits. But a cheapola like me can also use the secondary hanger with the end ground off. It is just long enough to turn the APT screw. In all the carbs I have taken apart the APT was always between 3.5 and 4.5 turns. Thus 4 turns is a good ballpark adjustment.

Hey guess what? It HATED 2 1/4 turns. It's at 5 right now, 4 wasn't enough for a free rev without a lean pop out the exhaust.