Idle Screw Settings

[corkman]

I have a 2003 VMAX and just cleaned the CARBs. I noticed that all four pilot screws were screwed all the way in. When I looked at the service manual it said they were "Preset". I thought that it was odd that they would all 4 be "preset" to all the way in, I am used to them being backed out 1-3 turns.
Anyone know what the initial setting should be, before I fine tune them once I get it running?

 

[naughtyG]

If there weren't plugs in the holes stopping you from accessing the A/F mixture screws (I assume that's what you meant by 'pilot screws') then they have been tempered with.

When they are preset at the factory, plugs are stuck into the holes which have to be drilled/picked out before you can get to these screws.

We usually use 2,5 turns out as a 'default', and go from there. There is no way to adjust them properly without an exhaust sniffer telling exactly what the A/F ratio is. These are usually found on dynos.

Also do make sure each screw is fitted with its spring, metal washer and o-ring!