how to tune a carb

[bowtieboy4life2000]

ok so i got an international travelall with a 350 in it. and it has a carb, and i have no qule how to tune in. it came from oxnard so a 3000 foot elevation change makes a differents right? but i do know it is running rich so any help is good.

 

[chulisohombre]

2 barrel or 4 barrel?i always adjust as so.idle to around 700 rpm or until the idle starts to be rough then add 100 rpm.turn adjustment screws in,or to the right until it starts to lose idle or stumble again.then turn to left until idle comes up and stops.that would be your best idle mix.then put idel to normal spot.i put mine back to 1000 since i run a manual trans.coming from a higher elevation,the jets may have been changed also,so you may have to go to a smaller jet to limit fuel a lil.wide open throtle mix may need adjusting also depending on type of carb.

 

[badmix]

I tune my carb with a vacuum gauge. Ive got mine perma mounted in the engine bay.

First you want to make sure your truck is timed right and you have no issues like bad plugs, wires etc and make sure you dont have any vacuum leaks.

I adjust my A/F ratio to get the highest reading on vacuum gauge. This is around 17-18hg. Also you have to disco the vacuum advanced to adjust timing and all that.

When adjusting the a/f you may have to bump the idle one way or the other.

Once the A/F is the highest (you keep making 1/8 turns til it starts to drop off than you back it off a lil)

than you just set the idle and there you go.