Originally Posted by Werks

The thing that you have to keep in mind is that the high speed needle affects the overall fuel delivery. Think of it like your garden hose. You have a nozzle on the end which is the LS needle, but you have a tap at the wall which is your HS needle. You open the tap a turn so you have good water pressure flowing through the hose, then you adjust your nozzle so that the water shoots say 3 feet. Now if you go back and close the tap 1/4 turn the water will still come out of the nozzle but it might only go 2 1/2 feet. To get it to go 3 feet again you probably have to go back to the nozzle and adjust it a bit. The exact same thing happens with the carburetors. If you lean the HS needle that means that less fuel is flowing into the carburetor so you have also leaned the LS needle. If you want the same amount of fuel flowing through the LS needle then you have to go back and open it up (richen) slightly to compensate. This is what I was talking about in my last post. The issue that you are experiencing is a typical sign of an engine being set too lean and it basically over heating. So to compensate for that we are going to richen the HS a tad bit which should keep the engine from getting so hot. However you mentioned that when you first go out that the idle is perfect and the bottom is good, so it sounds like you have the bottom end setting good. So to keep this the same if we richened the top a few hours we now need to lean the bottom a bit to compensate just like with the garden hose. Make sense?