Rebuilding my first carb ever...happens to be on my first car ever....my 85 gs.

I'm going for the stock approach but considered the removal of emissions components, overall simplification, and possibly mechanical secondaries/accelerator pump mod.

Now, I've done my research but however I lack that little piece that will kick me in the *** and say "DO THE DAMN MODS" when it comes to the mechanical secondaries and accelerator pump. MY questions I guess are:


If I'm cruising down the road at 60 mph, is my mileage going to be just as terrible with the mechanical secondaries as when I'm getting up to speed?

Also, I know that I do not need the dashpot, throttle position sensor, altitude compensator (although I may keep it) and the air vent solenoid. However, do I need the richer solenoid? (correct me if I'm wrong on any of these)

I have all the links from the forum and sterlingmetalworks.com that I can use, so I would appreciate just some input/opinions rather than straight links to info I already have.

Thanks guys

 

And if I haven't mentioned, enlighten me to any other components I do not NEED on the carb (I want to keep the choke though for startup)

 

you need the air vent solenoid or else the carb cannot vent air. this will flood the float bowls

and in case you missed it, this thread highlights what all you can remove should your heart desire
https://www.rx7club.com/1st-generation-specific-1979-1985-18/carb-rebuild-how-strip-nikki-down-rx7carl-please-help-647576/page2/

 

Looks to me like the air vent solenoid is in pink....as in unecessary? But maybe im just retarded

 

It says to plug holes due to its removal???

 

maybe i was misinformed. idk. i thought i was right. maybe someone else can clarify? cuz on mine when it was flooding someone mentioned the avsv.

but yeah, vacuum leaks are bad

 

Although i was going to keep it because i was not going to try to block it off.

 

Based on its purpose....along with other units on the carb...i will keep them if their purpose is actually useful...not just emissions related

 

I would think that mech secondaries will lower gas mileage, as they will be opening more frequently even when load conditions do not demand it. No proof, though; just bench racing.

 

I switched to mechanical and the nice thing is you can physically control when they open. When I press the pedal down, I can feel when the secondaries are opening through the pedal. It's the last 30% of the pedal movement. As long as I keep the pedal above that point, I am only using the primaries and saving gas. Not to mention, you can't just stomp on the pedal or it will bog down. You have to ease into it until about 4000 rpm's, or substantial engine load, before kicking in the secondaries.

If there is one modification you ever make to your FB, it should be the mechanical secondaries.

 

I have always liked mec secondaries on any engine but DD is right you will use more fuel .. If nothing else just for the fact that you can feel the extra boost you will use them more .. If you are not concerned about fuel mileage go for it .. I set one up on a big block years ago and I made the linkage it was actually two pieces that slid inside each other and spring loaded ,, I made it so the link could be adjusted so that the secondaries would open at any throttle position .. It worked great but took me many hours before it worked well..

 

Very nice guys. Thanks.

I re installed the carb today, and everything seems pretty good. I also did an emissions removal/re route and kept only the necessary parts (per the maz tutorial).

That worked very well. My only bugs are that the choke is way more sensitive than it used to be, even with the linkage loosened. Not sure how this happened...maybe its something I left out on the carb? It doesn't max out around the high 2000s anymore...it can go to about 5000 rpm for some reason.

Not a bad thing I guess...the adjustment is still there and the response from the **** is still there so I can do like 1500 or 2000 if I want. Just wierd.

Only other bug is that the throttle cable bracket seems to be maybe a millionth off of where it was before...so the linkages are all slightly different in length causing the idle to be different. I know this because when I push on the bracket the idle comes down on the car...from moving the accelerator cable with it.

Maybe if I loosen up the accelerator cable just one turn or so I will have it where it needs to be hopefully. Definitely dont want to take off the carb to spacer nuts again (as it damn near requires the removal of the alternator to have any chance of success at getting at the one nut).

Overall...I think it went well for my first rebuild and emissions mod.

 

Right on DK The lord hates a coward .. Sometimes I take a video when I am venturing into uncharted waters .. The first time I took my spray foam gun apart for rebuild I took a video at least I thought I did until I looked after I had it apart and realized I forgot to turn the dam camera on ..

 

Well there ya go. Obviously you didnt need it in order to put it back together haha. And by the way, I just got my racing beat strut brace on today, so now it looks pretty nice under the hood. no more emissions crap, carb looks good, a 2nd gen alternator...and now the brace.

now all I need is paint...and unfortunately that costs way too much

 

A nice paint job is always a plus but to me the mechanics are more important .. some day you will get everything done that needs doing and then make it look better .. We use to drive all kinds of machines they ran good and went like stink but most didn't look so great .. It is surprising how many people judge a car buy it's appearance . For me it's not what's on the hood It's what's under it

 

Absolutely. Ive been workin on it for four years...driving it too. It has a lot of things done to it, and only needs one or two more things. Thats why im thinking about it.

 

Someone finally summed it up correctly,
+1111

 

I actually went from mechanical back to the vacuum operated... I have to say vacuum operated feels very good tooo when working properly.

 

FYI for ya, sir... at true idle, the throttle cable should be slightly slack, so pushing the bracket shouldn't vary idle. You may have it a bit too tight, and that's pulling the butterflies slightly open when they should be parked on the limit screw.

Oh, and congrats on the "got it running in one" result!

 

Ok very good. I figured out the bracket issue...and thanks for the congrats haha.

For those of you (pretty much anyone who has replied) with knowledge and more importantly, photos, I need to see what options (if any) I have for converting to mechanical secondaries. I have done some serious searching only to find one thread with pics in it....and it's hard to tell what the arm on the secondaries is hooked to.

any help is welcomed...I definitely need some better/different pics in order to see what would work best. I was out looking at the dang thing after work, o say 2:30 in the mornin because I wanted to see if I could figure it out.

 

https://www.rx7club.com/showthread.p...al+secondaries

hoepfully some of these pics will help me out. All I really have to do is 'tie' the small bracket on the secondary arm to the arm/link just above/in front of it?

seems too easy, but maybe I will have some luck

 

Figured it out....and tied them together leaving just enough 'looseness' to return to idle soundly. Noticed no difference when driving the car....so I'm returning to vacuum operation

 

Unfortunately I didn't get a chance to even see if the secondaries being converted worked for me. I meant to edit my post. I'm still having my 'shuddering' or sputtering experience when I push the pedal more than 2/3 of the way or so. and once I get to about 5k rpms (in neutral) it also shakes and misfires/sputters.

Ive been over the entire ignition system, just rebuilt the carb, and nothing has helped this problem. I'm thinking it HAS to be fuel supply. Pump could be weak after 26 years?

 

Fuel supply is perfect, no obstructions. Even took the primary and secondary jets out...but to no avail. Still shuddering and losing power around 4-5k rpms. Maybe one of the passages is a little gummed up? Im not sure anymore...I've had the carb off twice now to fix this...even took out the other needle/jet components from under the air horn and they all look pretty good.

 

have you measured the resistance of the spark plug wires? they should be less than 16K ohms/foot