RB Holley question?

RX-7 Chris · 11-20-2008, 03:20 PM

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 · 11-20-2008, 04:41 PM

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 · 11-20-2008, 05:11 PM

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 · 11-20-2008, 05:49 PM

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 · 11-21-2008, 10:35 AM

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

How tight should the seconds be closed?

BigTeddy · 11-21-2008, 03:03 PM

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 · 11-24-2008, 10:52 AM

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 · 11-24-2008, 11:00 AM

If that is the problem would this fix it.
http://store.summitracing.com/partde...5&autoview=sku

Rogue_Wulff · 11-24-2008, 12:12 PM

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 · 11-24-2008, 12:47 PM

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 · 11-24-2008, 12:59 PM

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/THROT...Q5fAccessories

Rogue_Wulff · 11-24-2008, 02:50 PM

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 · 11-24-2008, 03:08 PM

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 · 11-25-2008, 05:35 PM

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 · 11-25-2008, 06:28 PM

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.

11-20-2008, 03:20 PM	#1
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	RB Holley question? 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.

11-20-2008, 05:49 PM	#4
BigTeddy Rotary Fan in Training Join Date: Sep 2008 iTrader: (0) Posts: 46 Rep Power: 0	flaps on the throttle plates are not closing all the way... probably not enough spring back pressure to keep the seconds closed __________________ One Turbo At A Time

11-21-2008, 03:03 PM	#6
BigTeddy Rotary Fan in Training Join Date: Sep 2008 iTrader: (0) Posts: 46 Rep Power: 0	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 __________________ One Turbo At A Time

11-25-2008, 05:35 PM	#14
BigTeddy Rotary Fan in Training Join Date: Sep 2008 iTrader: (0) Posts: 46 Rep Power: 0	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 __________________ One Turbo At A Time

11-20-2008, 04:41 PM	#2
Rogue_Wulff Non Member Join Date: Jun 2008 iTrader: (0) Posts: 310 Rep Power: 17	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.

11-20-2008, 05:11 PM	#3
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	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.

11-21-2008, 10:35 AM	#5
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	I'm going to pull the carb again today, anything else I should look for? How tight should the seconds be closed?

11-24-2008, 10:52 AM	#7
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	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?

11-24-2008, 11:00 AM	#8
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	If that is the problem would this fix it. http://store.summitracing.com/partde...5&autoview=sku

11-24-2008, 12:12 PM	#9
Rogue_Wulff Non Member Join Date: Jun 2008 iTrader: (0) Posts: 310 Rep Power: 17	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.

11-24-2008, 12:47 PM	#10
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	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.

11-24-2008, 12:59 PM	#11
13b,ug The Newbie Join Date: Nov 2008 iTrader: (0) Posts: 6 Rep Power: 0	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/THROT...Q5fAccessories

11-24-2008, 02:50 PM	#12
Rogue_Wulff Non Member Join Date: Jun 2008 iTrader: (0) Posts: 310 Rep Power: 17	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.

11-24-2008, 03:08 PM	#13
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	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.

11-25-2008, 06:28 PM	#15
RX-7 Chris Rotary Fanatic Join Date: Mar 2008 Location: Colorado Springs, CO iTrader: (2) Posts: 132 Rep Power: 17	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.