i have a 302 in my 1969 truck and i have a new carb ,fuel pump,distrbutor, wires and voltage reg . i need help fine tunning it . how to set the choke rightand the air /fuel mix screws,and the timing . pls help[ vthanks
You will need a timing light and a vacuum guage.If the truck starts and runs without coaxing now.Run it, get it up to operating temp.Then set the timing(pull the vacuum hose off the dist before setting it and plug the hose)If you dont have a timing figure for the engine set it to 10 deg BTDC.With that done you can set the Idle mixture screws.Some people do it by ear,some read plugs,some use a vacuum guage,some of us crazies do all of the above and then some.Find a manifold vac source.You want constant vacuum at idle to do this properly.Now regardless of what type of carb you have this is standard proceedure:Turn the idle down as low as it will go and still run straight(the choke should be wide open for this)With the vac guage hooked up.Shut the truck off,close the mixture screws till they LIGHTLY seat,dont crank em in!turn each one open 1 and 1/2 turn.Start the truck up.You may have to nurse the gas a bit,If it refuses to idle turn the idle up a bit(just enough to make it run straight)Now look at your vacuum guage,and turn the mixture screw in slowly untill the engine stumbles.STOP,turn the screw out now untill you obtain the highest vacuum reading And idle(yes the idle will increase and drop as well as you turn the mixture screws) you can with out the reading dropping off(Turn the screw in and out a few times and play with the reading) untill you are satisfied with it.Repeat for other mixture screw)(Do both sides a few times to be sure you have achieved the best readings you can) Now set your idle so the truck runs smoothly in gear with your foot on the brake(get someone you reeeally trust)to sit in the truck with their foot on the brake and the truck in gear(Idling)dont rev it while you set the idle.Now drive it,Does it want to stall??or does it run well.If so dont mess with it!Now you have to let it get cold so you can set the choke.If it does want to stall or sputters when you step on the gas,(its too lean)turn the mixture screws out another quarter to half turn each untill it drives properly.If it falls flat on its face when you step on the gas,the accelerator pump may need adjustment as well.I dont know what kind of carb you are running so lets just leave that alone for now.Do these things first,then chime in with your results.My self or others will chime in to help you along the way.Good luck hope this gets you going in the right direction at least.
wow great info going to have to try it out i live in high altatude ang with your step that my work real well up here thnks got any more little tricks?the one thing we do up here is set timming by advancing it a little at time untell the truck has a hard time starting then you back it off i little
You put a new carb on - is it jetted for your altitude? If you are above 5000 feet the jets should be smaller than a carb sold for use at sea level. You might want to call the store and find out if the carbs they sell are jetted for high altitude or not. They may not know but they might buy them that way or at least know what jets you need to buy to set it for altitude.
