I found it. Here it is in case anybody else needs to find it.

I found the following in \CMSScripts\skmmenu.js and skmmenuup.js:

//Region Methods to hook up a menu to the global variables
function skm_registerMenu(menuID, selectedStyleInfo, unselectedStyleInfo, menuFadeDelay, highlightTopMenu){
skm_SelectedMenuStyleInfos[menuID]=selectedStyleInfo;
skm_UnselectedMenuStyleInfos[menuID]=unselectedStyleInfo;
skm_MenuFadeDelays[menuID]=menuFadeDelay;
skm_highlightTopMenus[menuID]=highlightTopMenu;
}

Change:
skm_MenuFadeDelays[menuID]=menuFadeDelay;
to
skm_MenuFadeDelays[menuID]=<new value>;

//Region Fade Functions
function skm_doTick(menuID){
if (skm_clockValue>=skm_MenuFadeDelays[menuID]){
skm_stopTick();
skm_closeSubMenus(document.getElementById(menuID));
} else {
skm_clockValue++;
skm_ticker=setTimeout("skm_doTick('"+menuID+"');", 500);
}
}

chang 500 to new value and after chang you must restart appliction in cmssitemanager