I'm trying to see if my idle screws need adjusting. I think they are Hex Heads between 4 and 4.5mm... Maybe 1/8"?? Does that sound right ?? Carb is brand new, car runs great, just smells a little ruch if it idles for a long time and smells like there s a fuel leak when sitting at a show. Can't find leaks so I'm wondering if it's a little bit rich at idle.... I'm trying to adjust with a 5mm but I don't think I'm doing anything. No real RPM or vacuum change if I turn the screws (unless I'm really not turning them).
The screws should be slotted,why not just turn them with a screwdriver? You should be able to stall the engine by turning them all the way in. If you can't, that is an indication that the carburetor isn't running on the idle system, but instead on the main system. Biggest contributor to that is either the wrong carburetor for the application, or the throttle screw being too far in (throttle plates open too much) due to insufficient ignition timing at idle, or again, the wrong carburetor (for example, a small block carburetor on a big block)
Larry - The carb was built by Everyday Performance for my car, so I know it's right... There is no slot in the screws... And my timing is set per your Power Timing thread so I'm pretty sure the timing isn't insufficient. I'm running 16dg at idle w/o Vacuum, 22 with vacuum...
you need one of these john it has the right hex on one of the tips. I think its 4.5mm http://www.northerntool.com/shop/tools/product_200396137_200396137 that 17059241 carb doesnt have screwdriver slots unfortunately.
We sell slotted mixture screws for the 1979 and later units with the metric threads. They can also be opened up to 10-32 threads and use the old style mixture screws.....Cliff
Thanks Ken, It is running really well. Still bogs as the secondaries open, but if you accelerate slowly until you pass the sweet spot, it will pull until you let off... So, I think it may be tranny related because it doesn't downshift at speed and still has hard downshifts when you stop. That's a job for a tranny shop to figure out. I thought it was rich when I was cruising earlier this week at Back to the Bricks in Flint, but then when I had to go somewhere with my regular car my eyes burned just as bed, so I have concluded it's all the OTHER cruisers that are rich !! I'm leaving it alone until i get the trans looked at and then we'll see...
Which transmission? THM 350 uses a cable (is it there?), and the 400 uses an electrical connection (is it hooked up?) You don't need a tranny shop for that. Easy to diagnose.
` It uses an electric kickdown just like the 400. Check to make sure the wire is connected, and that 12 volts is making it to the transmission when you floor it.
Where is the switch ?? The 2bbl set up had nothing on the intake or carb that was electrical and the 4bbl I put on doesn't either... Is the switch at the gas pedal ??
It should be at the gas pedal. Look on the drivers side of the transmission. Is there an electrical connection there?
