Reviving NOS Webers, Initial Settings? |
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Reviving NOS Webers, Initial Settings? |
bbrock |
Mar 20 2019, 08:55 PM
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#1
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914 Guru Group: Members Posts: 5,269 Joined: 17-February 17 From: Montana Member No.: 20,845 Region Association: Rocky Mountains |
I didn't want to hijack the other thread but have a question about my own Webers. They are Italian 40IDFs I bought in the late 80s or early 90s. Other than finger tight bolting them on to my engine to see how cool they looked, they have never been used. No fuel has touched them. I don't remember if I even opened them to set the float levels. BUT... they were stored in a humid basement for several years before I moved to a civilized climate. So, the magnesium housing is tarnished on the outside and the plating has deteriorated on a few of the levers and such. Pretty minor stuff from what I can see.
My question: is there is anything special I should do or check other than inspecting for corroded parts and normal setup as I prep these for service? |
IronHillRestorations |
Jun 20 2019, 06:53 AM
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#2
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I. I. R. C. Group: Members Posts: 6,707 Joined: 18-March 03 From: West TN Member No.: 439 Region Association: None |
Here's my carb tuning procedure from a March 03 post:
Assumptions: the carbs have the optimum jet and venturi package (if you have an unknown engine/cam good luck on this one), the float level in the carbs is correct, the cams are correctly timed, the valves are properly adjusted, the ignition timing is dead on, you have the proper spark plugs for your engine, the linkage is good, the fuel is good, the engine is good. Remember that the mixture and air bypass adjustment screws are precision needle valves, not head gaskets. Use your fingers to tighten them, not your fist. Start and warm up the engine. Make sure the two drop links for the throttle linkage are exactly the same length, and disconnected. You can use a 8mm thin ignition wrench to snap them off. Turn the mixture screws all the way in and then 5 half turns out. Turn the air bypass screws all the way in. Turn the idle speed screws out til it just touches, and then in 3 half turns. (3 barrels I go 5 half turns) Put on your hearing protection and start the car. Use your STE and find the barrel that pulls the most. We'll call this one baseline. Balance the barrel in the other carb that pulls the most with the idle speed screw. (if you have a Uni-syn, give it to someone you don't like and purchase a STE airflow meter) Go back to the other carb, with the baseline barrel. You will have one all the way in, then use the air bypass screws and balance the other two barrels. Go to the other carb and do the same thing. Snug the jamb nuts on the air bypass screws. All six barrels should pull the same amount of air at this point, if not repeat air adjustment procedure. Snap the throttle linkage drop links back on the carbs. If the idle changes then you need to barely adjust the linkage mounts so snapping the drop links on, doesn't change the side to side idle balance. Use the hand throttle or a vice grip and rag to lock the linkage between 1400 and 1800 rpm. Start back at the baseline barrel and adjust the mixture screw in or out, to get the smoothest running and highest idle, then turn it in 1/4 turn. Do the same with the five other mixture screws. If you have to turn the mixture screws more than two turns either way (from baseline), you've got the wrong jets. Recheck side to side and individual air balance, adjust as needed. Road test the car. If you get snapping and poping out the intake, it's generally a lean condition. If you get heavy exhaust fumes, or pboofing out the exhaust it's probably too rich. If you get a flat spot or popping out the intake at between 2800 and 3200 rpm, you probably need larger idle jets. That's a rough, five minute draft of my carb tuning proceedure, hope it helps! If it goes good it should take about 45 minutes, if not about three years. PK If it's running good but a little rich, you can turn each air bypass screw out to lean it out some, go a half turn out at a time and test drive. Make sure you turn all screws the same amount. This was written 16 years ago before wide band O2 sensors were economical and easy to install, get one it will make your carb tuning much easier. |
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