su swap done now stuck at full throttle

[zcars4you]

help! just installed su's on my 73 now it looks ok,linkage moves properly,butterfly moves ok choke seems ok. as soon as it starts it runns wide open, is there something internal that could be stuck. also have read here that you should use the larger spacers but the studs were to short to get the nuts started,so I used the smaller ones,could this be a problem?

thanks Doug

[wfl_colorado]

Doug,

I did the swap and I didn't use the big spacer. Not sure why you would need them. Are your chokes working properly? Are your float and mixture screws adjusted. Did you put oil in the carbs? It could be several things. I am going through the same swap and I haven't gotten all the kinks worked out either.

Bill

[ChrisA]

Hi Doug,

I used the big spacers from the SU's with the long studs from the earlier manifolds. Just because they were handy.

I would check to see if the chokes are on. Loosen the screws that secure the cables on the choke/throttle arms. They should return to zero due to the springs with the wires loose. Then try and start the car. If it was the chokes the RPM should be at or near normal.

Reach under the carbs and press both nozzles straight up. They might be stuck and not returning to idle either. Bent needle?

Good luck.

Chris

[wfl_colorado]

Maybe someone can chime in regarding an open vacuum line and how that would affect the running of the car?

Did you remove everyting from the balance tube?

[beandip]

The thicker insulator is just that a insulator between the carb body and the intake . Helps in hot weather to keep the carbs cool. A vacuum leak will cause a lean mixture which will cause a high idle and also the probability of burned valves. Doug, make sure the balance screws are set so the idle will be down to about 1K . When you start doing the mixture adjustment. If the linkage is not binding and is free to function smoothly . Look at the balance adjustment for the cause of he high idle . Providing you did install the two return springs . One more thing, If you have removed the butterfly disks from the throttle shafts , you may not have aligned them to the bore of the carb body. If this is the case you will have what you are experiencing. If this is the case , remove the carb and look through the barrel holding it up to a light source. With the adjustments backed off the butterfly should seal all the way around . Not allowing any light to show at all. If there is light showing then loosen the screws holding the disk , just to the point so that it can move with some friction. Snap the throttle closed sharply a couple of times , and look and see if the gap is gone . When all the gap is gone, tighten one screw and remove the other one. Apply some loctite to the screw and reinstall it . Remove the second one and do the same thing . Reinstall the carb and readjust . Hope this answers your questions and helps with your problem . Gary

[2003z]

Did you attach the throttle return springs to the heat shield? I forgot to on mine once and had the same problem, well not wide open, but when I stepped on the gas, it stayed there.

[zeiss150]

I had that problem once and it scared the $hit out of me. what was happening was that the linkage between the carbs was put back together wrong. I had to take the back carb off and figure out how to put the linkage back together right. Once I did that it was just fine.

I supose that if you wanted to make sure that was the problem just take out the throttle linkage between the carbs and if it still does it, then thats not the problem.

Good luck!