My newer stock savage 4.6 x was running great until all of a sudden it starting running super rich and doesn't seem to run right. I've went back to factory settings as far as needles, tried retuning numerous times with the same results. It'll idle fine, but will stall when it revs with alot of smoke. Again, I've leaned/richened numerous times. I'm new to the savage, but have been into nitros for awhile. Anyone have these issue's on these motors?
I used this as a refresher when I got back in rc:
-make sure you're not running old cracked fuel tubing, no leaks in that or your carb. As others have said check your glow plug (just pull it out and put it on an igniter to see if it's glowing bright warm)
-set carb to factory defaults
-start engine and let it warm up before attemping to tune, give it 1/4 - 1/2 throttle until it's up to temp
-adjust HSN first, LSN second, idle last
When adjusting HSN, at WOT (wide open throttle) there should be smoke, engine should be running smooth. Lean it slowly until it wants to sputter or cut out then back it 1/4 turn. Keep richening until there's smoke with no sputter at WOT.
When adjusting LSN it should rev quickly without sputtering. If you accelerate hard and come off of it the engine should barely hang up on higher rpms as you come off the gas. If you rev for 2 seconds or more and come off, if it hangs onto high rpms you need to richen. If you rev quickly and it sputters/bogs you need to lean.
Then you can adjust your idle to where it doesn't cut out.
If you have a mid range needle I would just keep that at factory settings and never touch, unless something absolutely is off.