oldsguybry

hey , I've been having an issue with my carb on my 72 CS, does not like to kick down , I have to hit the gas in order to get the idle to go back down....and in some cases that wouldnt work either , until I opened the hood and did it manually....when I get home from work I will post a pic on the part or parts that keep getting stuck.....also I have a 455 thats been sitting in a garage for about 4yrs , and I was wondering if there is a procedure to lube up cylinders or get parts moving or broke free if that is necessary , prior to starting it for the first time. I may need the carb from the 350 , cause thats the better of the two carbs , and they are both Q-Jets and look the same , so I figured you could interchange them...any input would be great.

Bry

Rickman48

The Q-jet is not the same, internally, for both motors. 455 is jetted entirely different.
As far as the sitting motor, pull the spark plugs, and squirt some Marvel Magic Mystery oil into the cyinders, maybe 1/2 cup per. Screw the plugs back in, hand tight, and let sit for a week. Try and turn the motor both ways to break loose, getting 1 full revoution should do it.
After installation, crank it with the starter w/o the pugs should clean it out enough!
Hit the choke lingage w/some carb cleaner, let dry, and again w/WD-40.
Good Luck!

oldsguybry

I should be able to turn motor with a big wrench or socket on one of the pulleys , is this what you mean when I try and turn the motor , if so im assuming the bottom pulley bolt

oldsguybry

IN THE 1ST PIC.... the metal tab with the numbers on it is the part that I have to move to the right which will make the idle go down....I sprayed the crap out of these parts and used WD-40 also and I still have the idle sticking problem , seems to be internal....he he , I think some of the parts around the carb were not meant to be sprayed with WD-40 as I found out the hard way....now my gas pedal goes down alot easier than it use to , making the idle stick problem even worse....notice in the second pic , the hose with the screw head sticking out of the end of it located right next to the fuel line by the carb ...any ideas where that hose use to go to ?

MDchanic

Please explain the problem further.

If you are saying that when you first start the car, the choke sets and it idles on the fast idle cam, and that the idle remains at the fast idle setting until you kick it down, then that's the way it's supposed to work. Back in the days before fuel injection, all cars were like this.

If you are saying that when you kick it down, it still doesn't slow down, then the fast idle cam (that tang with the numbers on it) is sticking, and may need to be removed and cleaned in order to work properly.

Your second picture isn't very clear, but it looks to me like the hose with the screw in it is ported vacuum for the vacuum advance. See the hundred threads on this board, and the million threads on the interwebs for discussions on the benefits of ported vs non-ported vacuum to the vacuum advance.

- Eric

Rickman48

And from what I can see, most of them shoud be replaced anyway - cracked and dry-rotted!
Has that choke pull-off canister any vacuum to it??

oldsguybry

most of them have been replaced , and not sure how or where to check canister , not to savy with carbs...also not to sure what you meant by turning the motor upon getting engine ready for 1st start , i commented on your post about the matter , but we went to other subjects

oldsguybry

yea , it doesnt kick down on its own , i can hit the gas and it will , but the minute you touch the gas pedal again , the idle is high once again....did not know about ported or non-ported threads or what that even means , sorry

Homestar

I had the same problem so I took a long look at the way it works and just taking apart a few pieces and sanding the corrosion off fixed it.

TripDeuces

"The Q-jet is not the same, internally, for both motors. 455 is jetted entirely different."

This is not the case with QJets for any make GM vehicle. I wish people would stop stating this like it's gospel. Rather than be called a liar here I've posted a link that clearly makes my point.

http://www.lbfun.com/warehouse/tech_...ng%20Paper.pdf

1) Go to page 13
2) The primary jets are clearly displayed for most Qjets
3) More importantly is the last column that shows jet area at WOT
4) There is also a column for cruise

One of the first things you'll notice is there is no rhyme or reason to jet area.
EI. Bigger engines get more area and vice versa.
Many of the small blocks have huge jet areas compared to the big blocks at WOT.
Even some of the so called High Performance cars have less area than the plain jane models.
I suspect that this is a function of the variable CFM of the secondary air flap.

The simple fact is you can take any QJet and slap it on any engine and it will more than likely run fine right out of the box. It may not be perfect but it will run but will probably need to be fine tuned for your application. If you read that article fully you'll see exactly what I'm talking about. When QJets run rich it's usually because something is leaking, something is sticking or the float is set wrong or bad.

MDchanic

Nice link. Brings together a lot of information.

I have to agree that that's been my experience as well.

- Eric

Homestar

Here in Rhode Island our State Inpsection machines have 5 gas analyzers for testing exhaust on cars older than 1996.

They can also be used in console mode for live readings for tuning carburators.
You just need to find someone willing to do it for you or let you use it for 30 mins for a fee if they will let you.
The hose that goes in the tail pipe may reach outside.

81 regency

Oldsguy,
I am going to help you with the idle problem in the following msg.
My first guess is that your choke thermostat the round black dics on the pass side of the carb is not opening all the way which will cause the return to fast idle problem.
CAUSE:
One of 3 things:
Primary choke pulloff which is the front vacuum break on carb is not opening or not set properly

Choke thermostat is not opening( round black disc with coiled spring behind it) Could be defective with age or not heating up due to a blocked tube which picks up heat from the manifold or passageway inside q-jet choke housing has become blocked with rust due to age and sitting. Also may be set too tight to start with and never will open properly.

My suggestions from lost of experience with this condition.
Check the above and let everyone know how you make out!
Good Luck!
Rich

oldsguybry

well , I should of thought of those problems a little harder and I would of had the answer.... carb sticking at high idle.... gas pedal easy to push down all of a sudden.....the stupid spring came off that holds tension on the cable that runs from carb to gas pedal it was like that for awhile too ....sorry i wasted anyones time on this subject.

MDchanic

It's always the simple stuff that stumps ya'.

Glad you got it fixed!

- Eric

Lady72nRob71

And just for reference, the fast idle and choke mechanics should be removed and cleaned throroughly, and reassembled WITHOUT any lube.
It is common for the fast idle cam to stick when old lube has solidified or collected too much dust and dirt. Had this issue with my Ford when i did not know better and oiled the mechanisms. After cleaning, it works perfectly.

TripDeuces

It happens to everyone, glad you fixed it.

oldsguybry

Thanks guys , the car drives alot better now...although it seemed to have more power the other way without the spring hooked up , I had forgotten that the part that the spring originally hooked to broke , so i hooked it on a metal clip , that in time slides down the alternator bracket making the spring loose enough to fall off....doesnt matter much , because the engine has a knock after warm up , and I dont have the money to get it rebuilt , so im probably gonna get the courage up to put the 455 in for awhile at least.