68falcon

iTrader: (2)

last time i filled up i reset the mile counter and when i filled up yesterday i had gone 140 miles and got 13 gallons of gas. 10.8 mpg cannot be good. what can i do to make it better. its all stock, i have a lot of smoke(black) especially right after i shift up, and it cuts of a lot. if i ever let off the gas it cuts of whether in gear or not. i think the carb has been rebuilt before but im not sure, i ve change the fuel filter twice, and saw no difference. thanks

Kentetsu

Sounds like the carb is flooding itself for some reason (running too rich). Not sure what would cause it though, could be a whole bunch of things. Start by looking down the barrels of the carb while the car is off, and make sure that the secondary "flappers" are closed all the way. Then, check it again with the car running. Also, check the fuel levels in the float bowls, they should be at the halfway mark in the windows (one in front, one in back). Start there and let us know what you find...

FB II

wow, i get almost twice that mileage with my turbo setup. definitely check the floats as kentetsu said. if they are a good bit higher than factory settings then the emulsion tube always see's the fuel and will force a rich tune. (something like that i just woke up sorry). this is how i have mine purposely set so it never goes dry under boost. unless you have a snail i would make sure the float fuel line is right around the middle of each site glass. if you need a picture, let us know.

68falcon

iTrader: (2)

yes, a picture would be nice, if its not too much trouble. i know absolutely nothing about rotary engines, i just picked this car up for 50 bucks, after it had sat in a field for about 3 years, and just wanted to see how good i could get it to run before i spent too much money on it.

68falcon

iTrader: (2)

oh yeah, its an 81 gsl if it makes any difference, thanks

FB II

The arrow is pointing to the front window site glass. you may have to clean some grime and crud off. the close-up picture is also the front site window and the red line shows where the fuel should be around. usually the halfway point of the carb.

DASUPACAT1

I get about 13mpg in the city.

trochoid

iTrader: (6)

With the car sitting that long, it's time to R&R the carb. Old gas sitting in it has probably turned to varnish and gummed it up, which can cause all sorts of problems.

A carb kit is 30-40 bucks and the Haynes manual has a decent section on rebuilding the carb. While you have it off, look into doing the rat's nest nest removal to simplify the re-install. If you don't feel up to doing the carb work yourself, PM RX7Carl or Sterling, they are the Nikki carb gurus.

wickyc

Its an air bleed, or a float either way your getting way too much fuel into the engine. if its an air bleed when you shut off the engine it will still syphon fuel out of the main nozzle in the barrel you can look into the carb when it is off, other wise it probably a float.

68falcon

iTrader: (2)

to trochoid's post, i took it to the shop(not a specialized rotary shop, just one we had in town) and the guy did a little to it, got it from almost not running at all, too running enough to get me to school and back and he said that he rebuilt the carb. im gonna look at those window sites this afternoon

trochoid

iTrader: (6)

If he rebuilt it, it should be running well, if done correctly, baring any other fueling issues you may with the car. A full rebuild is an all day job and can easily run 2-300 bucks at many shops.

I have 4 or 5 of these carbs laying around, because I don't care to mess with them. I have a mikuni and holley set up for my 12a-bp and I can change between the 2 in under an hour. It takes me longer to remove the stock carb, than it does to do the complete switch between the aftermarket setups.

68falcon

iTrader: (2)

I checked the window sites yesterday and they seemed to me a little low. Not to be too much of a noob, but how do you adjust them without having to take the carb apart, or do you. When i checked the fuel line it curved up on the outsides(we call it a miniscus in chem class), but the edges were at the middle, but the bottom of the fuel line was below. And could someone expain what the secondary flappers are? thank for all the help

68falcon

iTrader: (2)

whats a good manual for the car. my local library has haynes i believe

ray green

iTrader: (14)

http://www.wankel.net/%7Ekrwright/c.../85_manual.html

pimpncuba

i would check if you did the math correctly also. (i.e. - had 8 gallons of fuel, ran 140 miles on 7 gallons and then filled up 13). may seem elementary but i would rather find out i made an error there before wasting time ripping apart my car.

FB II

you must pull the carb top off toadjust the floats. it explains it very well in the link ray green posted. that is the factory service manual.

fishbulb95

Also when your done with the repairs i recommend changing the spark plugs cause they could be pretty fouled up from everything.

68falcon

iTrader: (2)

to the question about my math, it is correct, i filled the car up then reset the mile counter, then when it got low i went to the gas station and had put 140 miles (give or take a half a mile) on it then filled up agian. i put 13 gallons in the car which means i had to burn 13 gallons since the last fill up. 140miles/13gallons=10.769230769230769230769230769231 mpg (to be exact). im having some trouble with that link too ray green. thanks for all the help

fishbulb95

math looks correct to me

ray green

iTrader: (14)

Recently I was reading a 1985 Mazda add for the new RX-7 that boasted their car could get almost 500 miles on a tank of gas (16.6 gal, or something like that). That's 500/16.6 = 30 mpg, which gives us something to look forward to. I get about 24 mpg doing 80 mph on the highway almost all the time, about 360 each fillup, maybe more if I kept it at 55.

You can get the owners manual on ebay if you can't figure out how the link works, I got mine for about $20 + shipping but the last one went for closer to $50, plus shipping. But you can also pick up the Haine's manual, at AutoZone, for less than $20 new and it's fine for what you need.

Ray

68falcon

iTrader: (2)

thanks, i requested some books from the library one was a chiltons repair and tune up, and the other was a haynes shop manual. ill look in to buying some. are there any certain brand of spark plugs i should get

68falcon

iTrader: (2)

Another question, where is the best place to buy a new engine. Can you put a 12A in an 81 without a lot of modification, or would it be best to stick with the 12A

FirebirdSlayer666

iTrader: (3)

I think you mean putting a 13B in and you can do it, just need 13B motor mounts. You'd probably want to go with a 13B tranny too just because the 13B puts out more power and torque and you'd want a tranny that can take the extra power.

68falcon

iTrader: (2)

some times when its running bad it acts like im not getting any power, and that im just coasting, if that makes since

68falcon

iTrader: (2)

uh, i was at school today and went to go home, and it wouldnt crank, it starts to turnover but no gas comes into the carb. i think the fuel pump is bad. any good one that are cheap