460 gasser is finally runnin right???

After a complete rebuild and several issues along the way I think I have gotten her tuned-in so I think.
great power-good idle-and so on. Had a miss since I got it back together but I got that to go away. Had the same miss before the rebuild as well. I do have a couple questions because I have never had a 460 let along one that runs right to compare with. I was or am having trouble with it runinng rich-too rich. Had a lot of carbon build up on black wet plugs. Mind you this motor only has 10 hours on it. The build up was spotty and clummpy on the pistons along with an oilly residue all over on both-what I could see through the plug holes. I used a thin weight oil for break in and I'm wondering if the thin oil and carb setings both contributed to fouling the plugs and carbon build up on the pistons. or just the carb settings.

I Changed the oil from 5w-20 with zinc addative to 10w-30 and put in new plugs. The auto store did not have the autolite 386's so I did buy the hotter 388. Went to the other store and bought some 386's but put it the hotter ones for now.

I adjusted the carb again and the miss is gone. I put her to work for about 2-3 hours to get some time on her and clean her out. She ran great- good power ect

parked back in the shop and pulled a plug to see what was going on. Still dark on the outside along with some oily residue on the outisde of the thread face of the plugs. The electrode and porcelain is now a darker chocolate and dry. So I am getting some where! I could have fouled these plugs as well until I got the carb tuned in but not sure.

one questions I have is what is a perfect plug color-chocolate or tan or lighter yet. I was under the impression it should be a mid range tan?

Other concerns I have is the carb settings-no matter what I try my max power jet is turned in to about 2-1/2 ta 3 turns and the air miture screw is at about 1 turn or so out. If I start them at 5 turns and 2 1/2 turns she is way too rich and rolls black smoke at idle and has that miss.

I want to turn in the main adjustment scew in further to about 2 turns out but I worry about it being too lean. I dont want to lean it too much and find out by burning up a valve or other engine damage sooo. How would a feller know if its too lean. just not run right??

I really want to open up the main screw to 4 or 5 tunrs but I cant get the air miture to lean it out so it stays in.

I just worry cause I know the max power is at about 5 turns and starting point for the air should be 2 1/2. and I'm way off those settings

so question. could the carb have drilled jets or oversized jets. Should I not worry about the settings and continue to fine tune regardless where they end up or should I keep looking for a cause and try to get those settings in more of a normal range????? Do I have a special needs carb that does not preform in the normal ranges? Can some carbs be that different and I should continue on without worry.

I know I wrote a book here but I cant find a guy around here that knows any more than I do so I gotta ask the experts this site!



Just to add a note I have gone through that carb about 3 times now with overnight soaks, air, float adjustment and so on.

I'm certainly no expert, but I always thought you wanted a light tan color on the porcelain after using it for some time.

The factory initial setting on the main power adjust needle IS 3 turns out, and the idle mixture screw is 1 1/2 turns out, so if the 460 runs just fine at those settings, leave it alone and be happy.

Factory initial settings are ONLY a starting point and if you tractor LIKES something a LITTLE bit different, then that is what is correct for that tractor.

Well soaking over night with this NEW socalled carb cleaner doe not always get everything cleaned out . and sometimes ya have to clean the holes out manually with a stiff wire or number drills then blowing them out with compressed air. One other thing is that this gas sometimes leaves black soot on the plugs . And myself i would never run a multi grade oil in them but that is just me all of use around here that run the older gas tractors run 30 weight LOW ASH . Yes we have three different oils at the farm . we have the 30 Low Ash for the gassers and the 30 weight #1 for the diesel tractors and the 15-40 #1 for the skid steer and the Dodges .

I would say you have it pretty close, run it as is until the engine is completely broken in, the oily residue is more than likely due to the rings having not "set" yet, this will take quite a few more hours of steady work.
Re-check the valve lash after around 40 hours on the tach, they will all tend to change as the valves begine to "settle in", set them up a bit loose, and adjust only when warm.

The black sooty deposits were from running too rich initally, hot cocoa is close to plug color, to light tan, white is too lean, black is too rich, keep an eye on your rain cap on the muffler, should be slightly black from exhaust when working.
Settle for a little black smoke when pulling hard, not much, just a little, better to be on the rich side than on the lean side.
Take it out & work it, it will finally settle down, & you will find the correct balance on carb settings. Check the plugs around once a week, & go from there.

good info thanks