Carb Help

merkrotary · 02-14-2013, 04:57 PM

hi guys need a little help I got a 1984 rx7 12a with carb and cant get the secondarys to kick in what makes them work beside vacuum right now the only time I can get them to kick in is when idle is at 3000+ otherwise has a hard time reaching red line. Any help would be appreciated. Thank you.
Merkrotary

t_g_farrell · 02-15-2013, 08:54 AM

They are vacuum actuated. Not sure what the spec for opeing is related to rpm.

diabolical1 · 02-16-2013, 04:39 PM

i wish i had a photo handy because i'm not sure how well i'm going to do with explaining this, but if your secondaries truly are not working properly, i would first check the linkage. here goes (i'm doing this from memory).

on the firewall side of the Nikki you should see the main linkage, where the cable runs. next to the larger spring (with the rubber cover) should be a slightly smaller spring attached to a pivoting structure. there should be a spring-loaded rod sitting in that pivot. if it is not sitting in the pivot, the secondaries will not function the way they should. so far every Gen I that i've ever worked on with "broken" secondaries, invariably, that was the problem.

check it and see if it's your issue.

merkrotary · 02-18-2013, 12:29 PM

thank you sir there is no other spring there just the rubber covered one so if you could get me a pic to show me I could see what your talking about thank you
Merkrotary

dexspeed · 02-19-2013, 10:00 PM

There is a small spring inside the vacuum diaphragm that assists with applying pressure to keep your secondaries closed (without adequate vacuum). If there is a tear in the fabric, it may be preventing full operation. It likely is just an issue with the external linkage as I have only ever seen one torn vacuum bladder piece.

You could always just wire your linkages to your primaries and override the vacuum controls for complete mechanical secondaries and improved throttle response. It only takes about a half hour to do.

diabolical1 · 02-19-2013, 10:20 PM

forgive me. i'm old and like i said, i was trying to do it from memory. i just looked at one of my Nikkis. the second spring that i "remembered" was actually the spring that encircles the rod that i referred to. if you look at the main spring (with the rubber cover) at the top it's attached to a pivoting structure. the top of the spring-loaded rod looks sort of like Mjollnir (Thor's hammer) - don't laugh - it should fit right into the open end of that pivoting structure. i hope that helps you a little better.

02-14-2013, 04:57 PM	#1
merkrotary The Newbie Join Date: Jan 2013 iTrader: (0) Posts: 7 Rep Power: 0	Carb Help hi guys need a little help I got a 1984 rx7 12a with carb and cant get the secondarys to kick in what makes them work beside vacuum right now the only time I can get them to kick in is when idle is at 3000+ otherwise has a hard time reaching red line. Any help would be appreciated. Thank you. Merkrotary

02-15-2013, 08:54 AM	#2
t_g_farrell Waffles - hmmm good Join Date: Aug 2008 Location: Huntersville, NC iTrader: (0) Posts: 757 Rep Power: 0	They are vacuum actuated. Not sure what the spec for opeing is related to rpm. __________________ 1980 GS stockport, Fat Nikki, RB Dual Facetfuel pumps, Holley regulator, RB Street port exhaust, 2GDFIS, MR2 MK I electric fans, 2G strut bar, relayed fans, lights and fuel pump, LEDs Project Fat Nikki Budget 12A rebuild Video setup < $30.00

02-18-2013, 12:29 PM	#4
merkrotary The Newbie Join Date: Jan 2013 iTrader: (0) Posts: 7 Rep Power: 0	thank you sir there is no other spring there just the rubber covered one so if you could get me a pic to show me I could see what your talking about thank you Merkrotary

02-19-2013, 10:00 PM	#5
dexspeed The Newbie Join Date: Nov 2011 Location: Ottawa, Ontario iTrader: (0) Posts: 14 Rep Power: 0	There is a small spring inside the vacuum diaphragm that assists with applying pressure to keep your secondaries closed (without adequate vacuum). If there is a tear in the fabric, it may be preventing full operation. It likely is just an issue with the external linkage as I have only ever seen one torn vacuum bladder piece. You could always just wire your linkages to your primaries and override the vacuum controls for complete mechanical secondaries and improved throttle response. It only takes about a half hour to do.