HiTech Posted March 15, 2013 Report Share Posted March 15, 2013 baffled why having to back the two idle air mix screws almost all the way out before it will stay running at idle..normally half to one turn out its fine .i spent three hours cleaning and making sure every port is cleared on the metering block and carb body the best i could ... .2300 ford high compression tps motor ..651 roller cam normal idles at 2000 rpm ..73 jets .3.5 power valve .this is the first one i have had to back that far out in 10 years of running the 500...so it has me thinking the block maybe warped ..... Link to comment Share on other sites More sharing options...
jwmbishop Posted March 15, 2013 Report Share Posted March 15, 2013 baffled why having to back the two idle air mix screws almost all the way out before it will stay running at idle..normally half to one turn out its fine .i spent three hours cleaning and making sure every port is cleared on the metering block and carb body the best i could ... .2300 ford high compression tps motor ..651 roller cam normal idles at 2000 rpm ..73 jets .3.5 power valve .this is the first one i have had to back that far out in 10 years of running the 500...so it has me thinking the block maybe warped ..... How much idle vac - how far down on the idle set screw to get idle? You are describing a cammed engine needing a pass hole in the throttle plate - the plates are so far open to get it to idle speed they have passed the idle transfer slot (so not pulling through them) and you tipped into the main jets - requiring all that extra air from the screws... a .090 hole in the throttle plate (I recommend just buying the predrilled plates 11 bucks at summit with new screws) will allow you to close it back down and get the same rpm - but the idle transfer slot (and the air screw adjustment provided to it) will now have more effect! Link to comment Share on other sites More sharing options...
railer Posted March 15, 2013 Report Share Posted March 15, 2013 check the vacuum ,then put the right power valve in ,if its 7in vac then a 3.5 will be required just divide the vac to the power valve ,ex 14in vac = 7 pv Link to comment Share on other sites More sharing options...
HiTech Posted March 15, 2013 Author Report Share Posted March 15, 2013 vac was 8 inches last time checked ..3.5 is what we have used for years it is new .. min idle is 1800 . and did not backfire when starting ..or back lash when shutting it down ....i am going to check the timing and vac tonight ..thinking i have an issue with the timing ..plus ill check for vac leaks at intake to head and so forth ... Link to comment Share on other sites More sharing options...
4cylfordz Posted March 16, 2013 Report Share Posted March 16, 2013 Sounds allot like the little cork idle screw gaskets are torn but your welcome to bring the carb by if you want me to help y'all out with it. Link to comment Share on other sites More sharing options...
HiTech Posted March 16, 2013 Author Report Share Posted March 16, 2013 Sounds allot like the little cork idle screw gaskets are torn but your welcome to bring the carb by if you want me to help y'all out with it. you maybe right .. Link to comment Share on other sites More sharing options...
HiTech Posted March 16, 2013 Author Report Share Posted March 16, 2013 thanks jim .something i may have to try .i did not get the chance to fire it up tonight and work on anything motor wise .had damage to other areas i had to work on in order to make some laps saterday ...plus it is on jack stands with the exhualt facing the main part of the house ..i have a wife lol... Link to comment Share on other sites More sharing options...
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