RB Holley question?

[RX-7 Chris]

I have the RB 465cfm holley setup. My car will not idle below 1200rpm. the idle speed screw just goes loose even if I have the cable off. I don't have any vacuum leaks. what could cause this?

I have a SP 12A.

[Rogue_Wulff]

Make sure the choke linkage isn't holding the throttle plates open, and that the secondary throttle plates are closing fully. A missing return spring in the vacuum secondary diaphram can cause the secondary throttle plates to not fully close when the throttle is released.

[RX-7 Chris]

It has an auto choke on it that has a tube that goes around the header. I tryed starting the car with the choke mecanism off and it made no difference.

The return spring in the vacuum secondary diaphram is there. I pulled the carb to see if the secondary throttle plates are closed and they look to be.

The setup was new when I put it on and it has done this since new. The carb has been rejetted and AP jet changed. I also added a quick change vacuum secondary diaphram setup on it.

[BigTeddy]

flaps on the throttle plates are not closing all the way... probably not enough spring back pressure to keep the seconds closed

[RX-7 Chris]

I'm going to pull the carb again today, anything else I should look for?

How tight should the seconds be closed?

[BigTeddy]

your looking for tension, clean the parts too that might help...but the spring action is going to be your biggest find..much luck to you

[RX-7 Chris]

I pulled it out and cleaned it. The spring looks good. I did spray carb cleaner all over the carb and intake with the car running to see if there are any leaks. If I spray by the rod for the secondary flaps, the car will sputter and I could feel a little play. is that normal?

[RX-7 Chris]

If that is the problem would this fix it.
http://store.summitracing.com/partdetail.asp?autofilter=1&part=QFT%2D10%2D6&N=700+4294925239+4294809787+115&autoview=sku

[Rogue_Wulff]

Sounds like you may have a worn throttle shaft, or the base is worn, allowing slop in the secondary throttle shaft. If the wear is on the shaft, that kit you linked should repair the problem. If the wear is in the carb base, it will need to be bushed, and that kit doesn't include the bushings.
Only way to know for sure, is disassemble and inspect. The throttle shaft assembly is a bit of a pain to disassemble though. Those screws holding the throttle plates are never easy to remove, as they are normally swedged on the end of the threads.

[RX-7 Chris]

The carb is only 9 months old so this really sucks. where can I get the bushings?

If I could go back I would have never bought the carb from RB.

[13b,ug]

Holly carbs have shaft play from the factory I run a edelbrock/carter carb and it works great. But you can bush the holly carb with this kit. http://cgi.ebay.com/ebaymotors/THROTTLE-SHAFT-BUSHING-KIT-HOLLEY-AED-BG-DEMON-GRANT_W0QQcmdZViewItemQQ_trkparmsZ66Q3a2Q7c65Q3a10 Q7c39Q3a1Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQ hashZitem390004937243QQitemZ390004937243QQptZMotor sQ5fCarQ5fTruckQ5fPartsQ5fAccessories

[Rogue_Wulff]

I'm no fan of holley carbs. On the other hand, I am rather fond of edelbrock carbs. Nothing more than the old Carter AFB, but all new castings, and simplified to meet performance specs.
I have an Edelbrock 600 (Model 1405) on a 6 port 13B. Great combo.

[RX-7 Chris]

I have Holleys on everything else I own and have never had a problem till now.

I read a bunch on these carbs and it looks like they have teflon bushings on the Holley secondary throttle shafts when the carb is a vacuum secondary carb. I emailed holley to ask about this. I also asked if they sell the bushings.

[BigTeddy]

I have never had a problem with holley carbs...But at the same time i don't buy everything racingbeat or mazdatrix sells...Its too bad...You were better off buying the holley intake mani and going through jegs or summitt for the carb of your choice...

Hits up with any info you get back from the email

teddy

[RX-7 Chris]

I would have been. I ended up rejetting it anyway for the Colorado air. The high idle is the only problem I'm having. The car starts up on the coldest days without any problems and the car runs great. After opening the carb up I found there is no diference between the RB carb and a stock holley. The only change is the added brackets for the OMP, etc. When I called RB a while back, they tryed to tell me the jets were custom drilled.

I called holley a few months ago and they helped me through the jetting and AP jet and cam.

I have not gotten a response from Holley yet but I will post about it as soon as I do. There is a guy over on rx7club with the same problem so we will see how that goes as well.

[RX-7 Chris]

I never got a response from holley but I figured out the problem. There is a secondary throttle adjustment screw on the underside of the baseplate below the vacuum secondary diaphram. To adjust it needed a very small flat head screwdriver. I lowered the idle until it stopped going down and then I raised it back up a half turn.