Is that a 4barrel code?

[gag67sky]

Hi, after cleanning and taking several pictures, all I can read on my engine code tag is what you see... Is that a real NB code as told in the ref? Hope so !!!
Second question, what do I have to chek first on my carter carb as I can't tune the iddle at a reasonable speed ?? (It runs too high and the trans makes a bad clonk when I go drive or reverse from neutral....) I can even remove the iddle screw as it's uselessssss... please help meeee

[Special_Deluxe]

Carb issue first: Examine the entire throttle linkage from pedal to carb. Is anything making contact somewhere preventing the throttles from closing correctly? Is the fast-idle cam disengaging when it should? My '68 used to hang up and keep the idle fast even when the motor was warm.

Another possibility: Had an experience with a '70 Cad, the secondary throttle linkage (connected to the throttle plates at the bottom of the Q-jet carb) had been bent and was hanging the secondary throttles open a bit even at idle. Quick bend with the pliers and she was idling right on spec. Took about 4 hours of investigation (and pulling the carb) before I figured that out though

Casting codes: I'm by no means an expert but the three engines I have at the moment (68, 69, 70) and my old ones (71 and a 73) all have the codes on the lower left of the area in the picture, and there were other letters and numbers stamped further to the right hand side. There might be more codes lurking there, under the dirt. Then again that could be the code as they do seem to "wander" a bit!

In my experience the left hand digit seems fairly consistant while the right one is more variable. Im wondering if these were stamped by different people at different times, considering that the left digit would be the same for the whole model year whereas the rh one varied with the application.

Examples- On the 68 the first "P" is clear and distinct while the second is weak and hard to read. And on my '69 the "R" is in the normal spot while the "O" is two spaces over! Only the 70 motor has the two digits neatly lined up in a row. Of course, none of this may apply to a '67 in which case I've done a whole bunch o' typing for nothing

Best of luck and hope this helps!

[gag67sky]

Hi , thanks for experience,

The throttle linkage is completely free so I think I'll have to dig at the secondary butterfly, but there are so many links ands springs and stuff that I'm not realy hurried to do !!!! but I think so it's the right way, Is there any 'air screws' to check first ? If any knows.....

About the code, what you tell about your later engines seems to be right for mine as it looks like the two digits are stamped at different times of building...

Well if any of all 67' lucky owners can help, let us know !!

[Special_Deluxe]

Hi , thanks for experience,

The throttle linkage is completely free so I think I'll have to dig at the secondary butterfly, but there are so many links ands springs and stuff that I'm not realy hurried to do !!!! but I think so it's the right way, Is there any 'air screws' to check first ? If any knows.....

There's mixture screws on the front of the throttle body but they're generally used to adjust mixture, not speed.

Couple of questions: Is the idle otherwise smooth and steady? No surging or missing? What's the current idle speed? If the idle is steady and strong, but too fast, it may be a linkage issue even if there's nothing interfering with the linkage before the carb.

Also, what model carb do you have? Loks like an AFB but I'm a Q-jet guy so.... But the first things to look at are not carb-specific and apply to any brand of carb so hopefully, it will help

Playing Sherlock Homes a bit here, we have all the suspects in one room here and need to eliminate them one-by-one First thing I'd do is remove the fast idle screw from the equation by cranking it out three full turns so it makes no contact at all with the cam. Easy to reach with the engine off and the throttle wide open, and can easily be turned back in once we're done. That fast-idle cam is tricky and can hang-up even when the choke plate is open if the linkage is "sticky" so that's the first thing to look at IMO. If that fixes it, just a matter of lubing the fast idle linkage and resetting it, although in my case I simply backed the screw off and keep my big foot on the gas while she's warming up.

If that doesn't do anything look at the throttle shafts on the passenger side of the carb. There's a link between them that "bumps" the secondary throttles open as the mains rotate. At idle, open the throttle gradually, there should be a bit of "slack" taken up before the Secondary side starts to open. If it's somehow misadjusted and holding the secondaries open at idle this will increase the idle speed.

Next I'd shine a flashlight down the bores and check the throttle plates. If one is bent or damaged it will allow more air (and hence more fuel) to enter at idle than it should.

BTW, if I recall correctly your car has that transmission kickdown switch under the hood Is that interfering with the throttles in any way? Probably not, but easy enough to check.

All this can be checked in about five minutes with the carb on the engine, no sweat or swearing required. Hopefully, something will turn up.

There may be other issues that are specific to your brand of carb, hopefully someone with Carter experience can chime in here with some tips.

Best of luck and by all means please keep us posted!

[gag67sky]

Hi, Special DLX sorry for so late posting but I received my shop manual and with that and a lot of time I've been abble to fix the idle/choke mess (was probabely done by a 'baker', not a mechanic !). The newer problem is that my idle switch seems out, I have to test several issues I got in other threads this sunday/monday, 'hope this will be fixed !!!

[wrenchhead]

Hi! we were talking on another thread. I've got the 67 Buick,about your afb carter..... Ive got the same carb and had simular problem. My choke was sticking & float... causing hi idle. I sprayed wd40 on linkage & got it working smoothly & had to tap side of carb with a screwdriver to get float unstuck. After doing this 4 about a 1,000 times or every time i drove my 67, i finaly broke down & rebuilt the carb. Although my 67 is a 3 speed on the floor, i dont think i have as much linkage as you do. None the less, I think we have the same carb & rebuild isnt that hard. If i can do it, I know you can! Hope this helps.... keep me posted.

[Special_Deluxe]

Hi, Special DLX sorry for so late posting but I received my shop manual and with that and a lot of time I've been abble to fix the idle/choke mess (was probabely done by a 'baker', not a mechanic !). The newer problem is that my idle switch seems out, I have to test several issues I got in other threads this sunday/monday, 'hope this will be fixed !!!

I saw the posts about the switch-the-pitch trans issue over in 60's tech. Wish I could add something but I've never had that feature it was dropped after '67 and mine's a 68

I seem to recall hearing that the switch-pitch was on the same fuse as the wipers, but that was a long time ago.....other than that, maybe try tracing the wire to see if it's broken or shorted somewhere?

Wish I could be more helpful.....hopefully, it's something easy to fix!

[gag67sky]

Hi DLX, finaly my idle switch seems OK as it 'clics', but the selenoïd don't, so my next step is following the wire from switch to case plug as you say, then check the plug itself ( it also energise the downshit that works fine but maybe the tong's broken?? ). If there's no issue then I'll have to wait 'till this winter storage to remove the oil pan and check the wiring inside the case, and at last fix the selenoïd itself if it's the only way... Keep watching the story !!