hello everyone , I just bought a 1975 280z from a man on its way to the crusher. jeuses loves me . i got it runing but the fuel mixture is very very rich. my ? is should the fuel in the jets stay at above the jet when pulled down and below the bridge. after the car has been runing and turned off.this car has a n54 with round top su's with 0.90 jets and n27 neddles . but the fuel from the tailpipe would choke a horse and make you turn on our winsheild wipers. i set the fuel bowl so that the fuel is above the jet and below the bridge when cranked over . but after the car is runing the fuel is no where over the jets when pulled down . do i have a bad fuel pump? any help ? or ideal?

Mckrack? Is that you?:eek:

no im a newbie my name is mark

We want pics! Congrats on the new acquisition.

welcome!

sounds like you're in need of a carb adjustment/rebuild. take it to a mechanic or do yourself a favor and pick up the SU vids from Ztherapy and do 'em yourself. worth every penny, and then some!

thanks everyone for the replys . this is my frist 280z . im a painter/badyman by trade for the past 20yrs. and i have only redone one of these cars. i don't know the frist thing about the motors in them . just what's in mine. as far as a carb adjustment .im sure of that but i have done everything under the sun that i have read to do to them . and it seem to me everyone has a different way to do them . like adjusting the air fuel mixture before setting the choke flaps /butterflys. i truely would thing that the chokeflaps? butterflys would need to be in time with each other frist . how about adjusting the float. lets stick a bar under the flaot no lets mark the float blow 23mm down . there are so many different awnser. all i would like to know for now is should the fuel in the jets stay above the jets and below the bridge at all times after being pulled all the way down. wot or ideal. it seem to me that it should . thats what the needle is for to allow the fuel in and out by the engine speed . it sounds werid that a low amount of fuel in the jets could cause a rich mixture but the fuel is lower on the needle.so i wonder if i have a bad fuel pump weak so to speak. i geuss i would know for sure if i got the car out on the street because it would run out of gas but thats not possible right now . then again maybe my way of thing is just:stupid::stupid:. maybe its not even the carbs. but i did change the plug wire's and plugs frist. and the car seems to run great other then the fact it will drink a gallon of gas in 5 mins and blow gas smoke out the tail pipe like its on fire. with 0.90 jets and n27 neddles. its also got 170pounds compression all cyc. umm i don't know . im going to try a new fuel pump . then i geuss i will go with the high dollar jet/needle replacement. but i don't really see anything wrong with them and i indexed the needles but i have been told i am blind in one and can't see out the other one. a mechanic would save one big pain in the for me . maybe my mechanic skills just really suck. this car makes me happy im a painter if nothing easle.

the motor is a f54 and i want to say p92 head /n36 intake with 4bolt 69-70 roundtops. im thinking i will but a vacuum gage on this thing .maybe it's pulling to much vacuum . it's sure got plenty of gas:disappoin

probably a p90 head. no p92.

thanks for the refresher e racer you are correct.

What part of Arkansas are you from.

It is vary difficult to understand what you are doing. You are using different names for the parts and adjustments on these carbs. From what I have read and I think I understand , you have changed the float level in the carbs and raised the fuel level. If this is what you have done , you vary likely are dumping raw gas into the intake and flooding the engine. This would account for the rich smell of the exhaust. From there if you have altered the setting on the nozzles and needles then You most likely have everything out of adjustment. The video would be a good investment. These Carbs MUST be balanced one to the other. Both in air intake and fuel . If they are out of balance the engine will not run properly. Also if the mixtures of fuel and air is too lean you can likely burn the valves . Gary

i am in Harrison, AR just s of Branson, MO and have a good friend who is helping me with my carbs now. you can send me an email or privite message if you want to get together and i will introduce you to him. this guy is very good with the carb and fuel injected zs. z therapy has a great video on adjusting and setting carbs also. congrats on your z and good luck getting it running. there is a very active club with most of the members around LR,Conway,Russelville area that i belong to, but that is three hours away from me and we don't get together too often. here is a link for you and joining the forums is free. they might can help you if you are from that area.

http://azcc.ww4.us/