jeepinoffroad04

okay, so i have 2 85's w/ the 12A.... one runs GREAT but the oil pressure drops to like 20ish when idling.... besides that runs SMOOTH no smoke, no sounds... no nothing.... any ideas or is that just a sign to say goodbye?


next.. my other idles at like 1500 all the time, and i have to pat the gas 9 times (exactly 9 lol) or it will not start... i have messed with the idle adjustment and nothing (plus from one side of the carb it leaks a drop of gas here and there) ... so i know thats all carb problems... but when i take off it goes but if i get to about 5500 rpms and shift it blows white smoke (smells of gas) would that be due to carb issues as well?

i'm def. not a rx mechanic and they actually scare me (basically b/c of vaccum lines) but i can't find anyone around here, so this site is my only source!

thanks in advance...

cmanns

The other one probably is leaking from the coolant o-rings?

and the first, isnt 20-30 normal? My fb seems to have around 20-30 idle and shoots to 60ish when i rev.

jeepinoffroad04

what is the coolant seal? is that bad? (like i said i know nothing about the 7's so yeah) once the car starts it'll run like a bat outta hell lol (i drive it daily about 100 miles and drove it about 10 hours just this weekend).... sometimes the oil pressure (on the first one listed) seems to be like almost NOT there.. which is what scares me. the one that has idling issues always runs about 50-60 psi of oil?? well any more advice?

FunK73

iTrader: (6)

The coolant o-rings are between the intake manifold and the engine block.

20 is a little low but 30 at idle is normal, 60 at 3k rpm



as far as the smoke goes, are you sure you were changing the idle speed adjust and not the fuel mixture adjust? Being a rotary, that needle is especially important since it runs similar to a 2 stroke with its oil injection.

DivinDriver

iTrader: (15)

Second question sounds like a vacuum leak to me, possibly complicated by an over-lean mix or poor fuel delivery.

High idle that won't come down is the signature symptom of a vacuum leak. Having to pump a huge shot of gas to get the car to start is also symptomatic - - vacuum leaks make everything run lean, and rotaries need to start rich.

You are using the choke when starting, yes?

Fuel leaking from the carb is not good; your carb sits directly over one of the hottest-running exhaust systems ever installed in a production car.

Sounds like it's time to roll up the sleeves and get familiar with your carburetor and vacuum system. They look more complex than they are.

Changing your fuel filter would also be a good starting point, if you haven't yet.

Is fuel level in the carb bowls normal?

82transam

iTrader: (18)

^Agreed, time to get that carb off of there and check it over, possibly rebuild it (not very difficult) and the oil pressure is fine as long as it goes up when the rpms go up

Kentetsu

All kinds of information on these carbs can be found at Sterling's site: www.sterlingmetalworks.com He's our resident expert. You can find writeups on rebuilding, tuning the idle, stripping emissions, and all kinds of other good stuff.

Rev high + shift = white smoke: You'll need to get out and stick your nose right into that cloud and decide if the majority of the smell(s) is gas, oil, or antifreeze. The oil control rings can go bad, which can result in clouds of smoke when you let off the gas at high rpms. Lucas Heavy Duty Oil Stabilizer can help with this, if it turns out to be oil (which it most likely is).

jeepinoffroad04

okay so is it worse if its oil/antifreeze or gas making it smoke? i figured the carb change will help a lot, dropping idle speeds from 1700 rpms to 800 rpms (give or take) so i guess i got to do that sometime, and check out that site, my 2nd 85 idles at like 300 and has 20 psi oil presure then but if u go up to 750 like the book recommends it'll go to like 30ish so i guess its fine. runs like a champ too.. i'm very impressed... so the coolant seal is in the intake... gas is int he carb... were is the oil seal at you guys are talking about?

Kentetsu

Inside the engine. The only way to replace it is by rebuilding the motor. However, like I said the Lucas can handle all but the worst blowby...

74RX4

iTrader: (10)

12A fuel filters are cheap and often contribute to other problems. I would replace them first.

Check this hose carefully. If it splits it can cause hard starting and poor performance. https://www.rx7club.com/1st-generation-specific-1979-1985-18/hose-question-750125/

Your idle should be higher than 300, but not 1500. Should be around 800-900. Idle adjust screw is hidden from view. Don't adjust the mixture screw until you've tried everything else. Where is the gas dripping from?

jeepinoffroad04

the gas is leaking from the very part of the carb located towardt he front of the car.... i will diagnose hoses at work today, there are so many on this car its crazy, (i'm used to a 1971 VW beetle... i mean really there isn't even a hose on that car lol)... so if the engine is smoking, i should keep my spare around, is there any sites you can send a carb to and have it rebuilt and were is that idle adjust screw? so i can put it down, i messed w/ one screw and it did nothing, but i never could find 2 of them.... well anyways... thanks everyone!

Kentetsu

www.sterlingmetalworks.com

Sterling is our resident expert, and offers rebuilds and race versions of the stock carb.

74RX4

iTrader: (10)

Both screws are labeled in the picture.

DivinDriver

iTrader: (15)

Unless you have an SA style Nikki for some weird reason, in which case, they are here:



MAS = Mixture adjust
AAS = Air adjust = idle speed.

trochoid

iTrader: (6)

Normal oil pressure is 12.8-38.4 psi at idle, 64-79 at 3k rpm. So you're well within range. As for the 2nd one, sounds like it's time for a carb rebuild after you locate the vacuum leak. In my sig line is a link to the FSMs, factory carb manual, etc.. Download those and whatever else interests you and start reading.
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jeepinoffroad04

i think i'm just going to look at the sterling site, see what can be removed/moded from the carb and swap out the one from my good motor... my engine was doing some weird stuff yesterday (in the car w/ the carb issues) i'm kinda thinking it may be on its last leg... i added lucas oil stabilizer like our friend above suggest... i havne't noticed any smoke... it idles sparatic, sometimes it'll do 1500, sometimes, 1000, sometimes it'll cut off if i hit brakes... but yesterday when i got to my destination (about a 30 minute drive at 4k rpms (dont know how fast... speedo doesn't work lol) it wanted to idle rough and driving around town like it didn't want to get up and go at all and it'd like kinda shake around 4k rpms and even sounded different... like it was stopped up kinda... i had an exhaust (cat) go bad on a car b4 and it had no power period and ran like crap and wouldn't go over like 30... could my exhaust be bad?

jeepinoffroad04

so today i changed my fuel filter out and the car w/ the carb issues seems to start w/ less "pumps" but ofcourse idling is the same... it goes at 1500 sometimes and then will settle down to about 1000 or so... i still haven't found the idle screw... i have looked, my buddy has looked, a corvette mechanic (owns one of hte biggest restoration shops on the east coast) has looked and so have both the guys i work with (doing automotive stuff)... i am really not thinking this carb is the same as the pics... mine has the screw w/ the phillips head on it.. .and its screwed all the way in (thats how i got it)... but the other screwin the pics.. not there!

jeepinoffroad04

okay, well X all that out, to my 74rx4 (screen name) thank you!!!! some how i had just kept looking at the book, and the pics of the carbs w/ the screws on top of each other, and thats were we had all been looking, thanks to your pic (not sure how i didn't notice the difference the first 30x i looked at it) but found it!!! but ofcourse if anyone can guess... i'm home and didn't bring a single tool home from the shop! lol... my air mixture screw (the one i was told NOT to turn till i did the idle one) is ALL the way in tight... anyone have a rough estimate were it should be? (like number of turns out?)