1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

New FB owner, New to carbs! lol

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Old Aug 20, 2009 | 09:30 PM
  #1  
Atticus_'s Avatar
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its only a 1.3...
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New FB owner, New to carbs! lol

Ok so me and a friend went in and bought 3 1st gen rx7s for $200 2 complete cars and 1 parts car. neither of the cars run and mine apparently ran 4 years ago, was stored for winter and didnt start the following summer. so it has sat since then.

so far i have changed the dizzy and have spark, dropped the fuel tank, cleaned the fuel pickup out (it was clogged) and drained the tank. put new plugs in and a new battery.


so i have fuel at the rail and i dont think it is getting any further.

now i am a fuel injected guy, i have owned a turbo II for a while. never messed with carbs so i need some guidance. lol

shouldnt i see the fuel jetting before the throttle plates if i look down through the air horn?

I would appreciate someone letting me know where to start. I dont want to start taking the carb apart and screw it up more than it already is. i am assuming none of the setting have been screwed with and would like to keep it that way.

so what should i take off and where do i look to trace down why fuel isnt flowing?

thanks in advance!
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Old Aug 20, 2009 | 10:22 PM
  #2  
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Start off with the float glasses. On the front and back of the carb, look to see if you can see any fuel in the float glasses. You can't miss it. Odds are you don't, so begin beating the top of the carb with something wooden or tapping it with the back end of a screwdriver. Needles might be stuck. Needles operate with the floats, where when the fuel gets into the float chamber it will make the float rise. When the float rises high enough it will push the needle up and that closes off the gas until it drops back down.

Another quick test you can do (after you find fuel in the bowls) is flick the throttle a few times and look down the throats. If you see fuel squirt out then your accel pump is working.

I have 10 bucks betting that the carb will need a rebuild
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Old Aug 20, 2009 | 11:59 PM
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Originally Posted by Atticus_
shouldnt i see the fuel jetting before the throttle plates if i look down through the air horn?
With a carb, you shouldn't see fuel flowing in the bores unless:

1) you have vacuum in the bore, which means the engine is turning

2) you pump the throttle, which makes the accel pump squirt from the little nozzles in the top of the primary bores.

Fuel (more than a tiny bit) entering the bores when the key is on but engine is not turning, is bad - - means you are flooding, probably because the needles aren't seating.

Carbs basically are vacuum driven - - all works off of pressure differentials.

If you want to REALLY understand them, download and read this:

http://foxed.ca/rx7manual/manuals/ma...01979-1985.pdf

All the carb theory you'll ever need.
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Old Aug 23, 2009 | 11:47 AM
  #4  
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its only a 1.3...
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well thanks for the help but i just went ahead and bought a carb rebuild kit and took a crack at rebuilding the carb. figured if i could take it all apart, clean it, and put it back together no problem. the PO had tried to rebuild it before me, and was no mechanic. he had anti seize on the fuel line banjo bolts, and the access bolts for the fuel jets. also had anti seize on the needle seats and left an extra crush washer under one seat so it had 2 while the other had only one.

also looked like he did a bad job of trying to adjust the floats, so i readjusted them to the rebuild kit's specs. put it all back together and tured the key...

the car didnt even seem like it wanted to start at first. and i think the floats where stuck down when i first turned the key because fuel was flowing in quite a bit. but i kept turning it over and it started puttering, then plopping, then running barely on one rotor and i let the key go and started to give it a little gas. revved up and blew out quite a bit of smoke, then started running PERFECTLY! idle is a little low (500rpm) but besides that it is running awesome. really surprised it runs so well for the fact that it has almost 110k on it and has set for 4 and a half years.

pretty proud of myself for rebuilding the carb successfully. never touched one in my life until i bought this car.

so far i have 150 dollars total in this car (bought the carb rebuild kit and spark plugs) and all it needs now is the brakes replaced and i can start driving it hopefully.

i will post pics later on of my new project.

thanks for all your help, i will keep learning about carbs, and 1st gens in general.
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Old Aug 23, 2009 | 07:34 PM
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Old Aug 25, 2009 | 12:55 AM
  #6  
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its only a 1.3...
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been driving the car around, still runs great! have a few questions though if anyone wants to answer...

is the omp mounting location the same as on the 13b? I am going to take the junk out as i dont even think it is working, and run premix, i premix my TurboII so im use to it anyway. just wondered if the blockoff is close enough to the same that i can use a 13B plate. not a big deal to re-drill the holes to the correct location if they are a little off.

going to go electric fan since the clutch fan seems seized to the waterpump pulley. lol car never gets very hot. dono what it is suppose to be on the stock gauge, but isnt even near halfway. a little of 1/4 i would say. lol

the worst part of the car is the interior, has anyone used the dash cover that mazdatrix sells, my buddy's car has a mint dash in, so if he ever takes it out i will replace mine with that, but im trying to freshen up the interior so if anyone has any decent seats or door panels im interested. lol

also the brakes are in pretty bad shape, drums are locked and disk are rubbing. I was wondering about doing a rear disk swap, and what all is involved in that? different master cylinder, do i need to swap the whole rear end, or hubs?

if anyone would like to answer my questions, i would appreciate it very much, i am doing a lot of searching for all of this, but if you feel like giving me the answers here then feel free


oh btw, pics on the way...
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Old Aug 25, 2009 | 12:05 PM
  #7  
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Swapping in a disc/lsd rear end is no huge operation. I did not bother with changing the master cylinder or anything else, just threw the rear end in and went. Works great! Brakes are awesome, and all 4 wheels lock up at the same time.

Nice find for the money, and congrats on a succesful carb rebuild. Here is a link to a bunch of info, including how to tune the idle: www.sterlingmetalworks.com


.
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Old Aug 25, 2009 | 11:35 PM
  #8  
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its only a 1.3...
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so did the lsd rearends all have disk? cause i am getting a lsd with the parts car that came with the deal, but i havent seen the rear end yet but am picking it up this weekend. in that case i will just say screw replacing the drums for now and rearend swap it. really doesnt look like a whole lot of work.
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Old Aug 26, 2009 | 08:11 AM
  #9  
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Well, all lsd rear ends came with discs, but once in a while you'll run across a bastardized setup where someone installed the lsd into a drum rear end. Easy way to check is to jack up the rear, and turn one wheel.

Wheels rotate in opposite directions = open rear end
Wheels rotate in same direction = lsd rear end
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Old Aug 27, 2009 | 08:34 AM
  #10  
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its only a 1.3...
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well the lsd rearend i am getting is the WHOLE rear assembly. the car it came off of has nothing under the back half of it, so it will be fun trying to pull it up on a trailer with no rear suspension or wheels. but i havent seen the rearend yet, (it is in the guys garage) but i assume he has the calipers and hub assemblys as well.

but anyway, the other day the brake line that runs to the passenger side in the rear busted from rubbing, and being under the heat shielding on the axle. it rusted from mud and gunk getting trapped in there and now i need to make a new line or replace it. but for now it is crimped off so i can move the car around.

Pics are still coming...
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Old Aug 27, 2009 | 12:23 PM
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Thanks for posting the link for the carb book. It helped a bunch. Big kudos!!
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Old Aug 27, 2009 | 12:48 PM
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Originally Posted by ArmyOfOne
Thanks for posting the link for the carb book. It helped a bunch. Big kudos!!
It's Sgt. Fox's link - - I'm just a 'helper.' His document collection is beyond price.
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Old Aug 27, 2009 | 07:47 PM
  #13  
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its only a 1.3...
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From: Madison, Indiana
Pics!!!

Here is what the car looked like when i came to pic it up:





Before and after...lol


Racing Beat Road Race header!


Cleaned her today:






This is the other car my buddy got, both cars plus a complete parts car with a locked motor. all 3 together was $200. he paid 100 for his 2 and i payed 100 for the gold one. but we are actually sharing the parts car.




did i get a good deal? lol
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Old Aug 27, 2009 | 08:25 PM
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You stole those cars, and I'm telling!!!
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