Carb adjustments

[cckutchma]

4 BBl Q-Jet Just finished rebuilding her. ( Had to be a her, tough just tough!! LOL 1ST Time doing it ever!! Anyway I cannot remember to save my life, on the front air/fuel adjusters, which way to turnto close and then is it 1 and a half turns back to about the norm? Kind of cool it started first tug but is smoking a bit let me know. Thanks

[eagle23]

Congrats! I have never had the stones to try a rebuid on my own!!

I understand to start two turns out from full in (max lean) and then go from there, a quarter turn out per side and go for max vacuum or idle speed. Where it ends up varies, but have heard that 3-4 turns from full lean is not uncommon?

Others with more experience will chime in, I'm sure.

[cckutchma]

Yes I think so... however to tighten all the way own is to turn to the right. You know righty tighty? Lefty loosey? MAybe Ive been sucking on too many Carb cleaner Fumes. Messed with it more y-day went all the way to the right and 1-2 turns to left and still lot of smoke and some fluid? also looks like a burnt hole in my exhaust manifold any quick fixfor that??? JB Weld take me AWAy!!! The thing that gets me is it sounds like the engine is in good timing... Thanks for your replies

[piecesparts]

First of all CHECK the timing on the motor. I usually set my timing advanced toget the most out of the RPMs. After that is done, then I would set the idle/fuel mixture screws at 1.25 to 1.50 turns open to start the engine, then I would complete the adjustments using a vacuum gauge. This way the carb is set to optimum on the idle/fuel mixture.
To do this connect a vacuum gauge to any intake manifoldvacuum, Not the carb's ports, that way you get the direct vacuum signal to the gauge. Then screw one mixture screw in to get a drop in RPMs, then turn the scrrew outward until the RPM increase stops and hold there. Now, do the next screw the exact same way. Now that the screws are set close to each other, perform the operation one more time. This way you set the mixture as close as possible to correct. Once the screws are returned to their outward position, turn them in an 1/8th of a turn. You are done and the fuel mixture is set.

If you are running rich with the screws turned in, then there is probably something that is not right in the rebuild. Explain the comment you made about smoke--is it black or blue in color? Black is fuel related smoke and blue means that you are burning oil from the engine. Don't quite get the fluid part either.

[tkeduk8r]

amen to that... that is the procedure... invest in the vac gauge... you will make the money back in fuel savings alone in the first few tanks... but the procedure is right on... not that hard to do... any questions let me know..
-Mike

[cckutchma]

Sorry about the delay guys, Just trying to take care o business. Pieces, with the smoke/ moisture issue is pretty well taken care of. So do you set your timing to 12 degrees 10 or 8??? you see I have set the timing on mine, The engine seems to idle very well, I take it for a ride it seems to run well, not great and when I come to a stop it seems to want to stall and sputters until it picks up some rpMS.hOW do I reset the fuel adjustments on the carb.Do I turn to the right with the engine off or on AND then turn the RIGHT (all the way or when the engine sputters??) Thanks for you input and patience with my lack o knowledge.

[piecesparts]

I used to set my timing around 12 to 15 degrees BTDC and then adjust everything to that. However, I now use an adjustable zero timing light and I adjust my distributor for "TOTAL ADVANCE", rather than using the initial timing setting. I adjust my distributor to get a toatal advance of 36 degrees and that seems to work fine for my present setup. I have a small block Chevy motor with a Comp Cams roller setup in it. The idle is set at 800 RPM with the truck in gear.

First of all and the most imprtant of all---Do you have a computer controlled distributor? If your distributor is controlled by the computer then advancing it will confuse the brain some. If you happen to have an HEI distributor that does not have a computer influence then advance your timing to get a better operation. If you don't have a advance timng light, then I would adjust the timing to around 15 degrees and drive the truck. If it starts and runs good (without a ping on acceleration or a dieseling effect when you shut it off), then leave it there. If it does either of the two items mentioned then back off on the timing until the problem quits. I never have run my timing around 10 degrees, it always has been set at greater than standard setting, usually between 12 and 15 degrees.

As for adjusting the idle mixture screws, do this with the motor running and sitting at idle (around 750 RPM). Make sure you have your timing set to where you want it first. Take the screws and turn them in (to the right) until they bottom out. Now back the screws out to set the vacuum setting as discussed above (turn them to the left). The motor will sputter and falter with the screw run in to the seat, but if you are good it will pick up as you turn it back out. Remember this si something that you cannot screw up. If the motor dies, just set the screws to 1 1/2 turns from the bottom seat and start the truck again.

[cckutchma]

Pieces Eureka I did all that however I had to remove the carb and adjust the plunger of the float. When I rebuilt it I was telling my Dad that there is no way that this will hang on how loose it is, so I crimped it tight to the brass part of the float. I read that I cannot do it so I adjusted it pu the carb back together slapped it on (used your advice on timing I'm at 12 deg tdc) dont have a vacuum gauge, But she i running pretty damn good for my first time. Hey once again Thanks for your input. Well on to my next project or 100? Its neverending but the feeling of accomplishment is cool....

[piecesparts]

OK So now drive it, like you stole it.