460 running too rich

I"m trying to fine tune 460 gasser after a complete rebuild but I"m having a rich motor problem. It runs way to rich. The plugs are very dark. I have rebuilt the carb/ adjusted the float and everything I can think of but still cannot get it to run lean enough. If you run her up in rps it cleans out but after you drop her back down it runs good for a while then develops a miss which is richness related. I have adjusted the carb everyway it can be adjusted and cannot get it to lean out. what should a feller look for now? Hotter plugs? hotter coil?
After the rebuild I replaced the old plugs with new ones. Autolites were in there before the rebuild so I just got the same ones. I would like to get some champions- which ones should I get? I dont want to cross ref the numbers cuz I dont know if the autolites are correct anyways.

(quoted from post at 09:52:24 02/02/12) I"m trying to fine tune 460 gasser after a complete rebuild but I"m having a rich motor problem. It runs way to rich. The plugs are very dark. I have rebuilt the carb/ adjusted the float and everything I can think of but still cannot get it to run lean enough. If you run her up in rps it cleans out but after you drop her back down it runs good for a while then develops a miss which is richness related. I have adjusted the carb everyway it can be adjusted and cannot get it to lean out. what should a feller look for now? Hotter plugs? hotter coil?
After the rebuild I replaced the old plugs with new ones. Autolites were in there before the rebuild so I just got the same ones. I would like to get some champions- which ones should I get? I dont want to cross ref the numbers cuz I dont know if the autolites are correct anyways.

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Stay with Autolite 386 or the hotter 388.

Does that carburetor have the electric solenoid? Is it working? You might consider replacing that solenoid with an adjustable load screw set-up as used on the letter series and 300 through 450s.

First off lets start with making sure that ya have the valves set correctly , Then make sure that you have the intake and exhaust manifold torqued to spec.'s Then make sure that you have the ing. timing set to spec.'s and off the top of my heead this morning with out going out to the truck and looking at my books i can not remember it to be sure . And you set the timing for full advance at full throttle . Then once you have that all done then let her warm up THEN you start to adjust the carb. set the main load screw to four and a half turns off the seat open . Then set the ideal RPM's to factory spec.'s then ya start on the ideal mixture screw and as the RPM's come up back off on the ideal adjustment screw and keep trying to get her to increase the RPM's as you adjust it and keep backing off the the ideal screw as you do this till ya get all that you can get . Another thing her is the gas you get makes a huge difference . On a 460-560 89 octane is what is called for . Getting the older gas tractors to run LIKE THEY SHOULD takes a lot of learning . NO IF you did the carb rebuild correctly and IF you got all the passages cleaned out then it will work ok . Do not go higher in heat range then what is called for and stay with the autolites they are way better then Champions.

float level is 1 5/16.
the main fuel adjusting screw should be 5 turns out for heavy pulling. but for idling around try 2 1/2 - 3 turns out.
turn the idle mixture either way to get a smooth idle and adjust throttle screw for slow idle of 450rpm.
make sure points and timing is set before carb adjustment.
also get it under load for a while to clean it self up.

Have you tired idling with the air cleaner out of the system to be sure it isn't clogged up and causing some of the problem?