problem with carbs ? after running for a while

[Robin260z]

Hi guys,

i'm robin from holland and bought a 260z 2 days ago.

(i will introduce me in a short time on the site )

The Z has some minor issues that have to be solve.

things like the rev meter doesnt work and lights etc.

But there is a big problem, i gues, with the carburetor.

The car starts immediately even when it is very cold ( now its freezing here ) and then with some choking the engine comes alive.

I know that the carburators arent'n being running that good, but i can drive the car normal with sometimes that the carbs wont get some gasolin for a second.

But said before, the carbs need some adjustment. When i drive around for a while en then stop en turn the car off it wont start anymore.

When i wait an half an hour of more the car will start again.

Does somebody had this before or knows what it can be.

I hope someone can help me.

thx

Ps. i know i had to search first but it is a big issue at the moment and want it to be solved as quick as possible. Also i didnt know the key words to search for this problem.

[Gary in NJ]

From the description it sounds like your car car has a vapor lock problem, i.e. the fuel in the fuel lines boils off from excessive heat and air gets trapped in the fuel line. This vapor lock is self clearing when the fuel line temperature returns to the normal range. The fuel return rail is supposed to keep this from happening, but in some cars it does happen.

As a "quick fix" you can try insulating your fuel rail and return lines. If I were you I would also check that the return line isn't clogged or disconnected/modified.

While this seems like the most likely resolution, don't rule-out a problem with the ignition system.

[ChrisZ]

Check your fuel filter and fuel lines first,they might be full of crap, how old is the gas, do you have fresh gas on the car?

Vapor lock in sub zero temps? i'm not sure about that and i never had that problem here just a little north of Holland, i believe it very well can be you ignintion coil that is bad, try to put your hand on it when that happens and see if it get very hot.

As a side note there is a set of carbs on ebay.de at the moment.

Chris

[Gary in NJ]

Vapor lock in sub zero temps?

Good call Chris. By the time I started typing I forgot where the poster was from.

[Robin260z]

thx for the fast response.

Well today it is freezing but the problem was there also when the weather was good/ high temps.

Where can i fine the return line.

I found out that there is a hose cut off but don;t know what it is for.

I made some pictures that i am loading up right now.

The car also made noise like i fires things of the exhaust. So there's also something with the timing/ ignition. Would changing the contact pointes and adjust make something?

[Robin260z]

when je look to the left you will see a cutted off hose. Can this be the problem?

Then tape on the right carburetor is there becaus the cap above the needle is broken.

The seller told to me that the needle was only to let the car drive smooth when opening the throttle.

her you see it in close up.

what i figured out is when i try to start the car again when in have run a while i have to put the gaspedal to the floor and the choke fully open. After a while the engine starts running again and then idle fine but when hitting the gas the exhaust is sputtering a bit.

i hope this will help you guys ?

thx again

[ChrisZ]

Robin, those are flat top carbs AKA "boat anchers" get rid of them and get that set on ebay.de or try to find some other SU here or here

Chris

[Bruce Palmer]

That hose looks to come off of the thermostat housing and must be plugged or you'd be out of water in relatively short order.

As far as the running issues go, those flat top carbs were not worth burying the day they were new and they haven't gotten any better over the ensuing 30 some odd years.. NISSAN replaced many sets of those when the cars were new just to keep their customer base from pitching a fit. A set of round top three screw Hitachis in good shape (which most aren't pushing 40 years old) should solve your problems.

Shameless plug -- We can fix you up with a set of remanufactured carbs and all the goodies to swap over.

[Robin260z]

well ok the temp meter isn't going higher then 60 degrees celsius so that can be the hose problem. Another point to look for.

when i bought the car the seller gave me an extra set of carbs which came from a 240z he said.

Will those fitt my 260 and is it better to use them instead of the original carbs?

[5thhorsemann]

DO NOT POST PICTURES OF FRESH SNOW!!! We got almost 8 feet of the nasty stuff here in Maryland last year, 5 feet of which fell in a 4 day period! That "LUMP" of snow shown in the second pic is on top of my Z, thought it would crush the suspension, 12 hours after this pic was taken it began to snow again, 2 days later there was another 31 inches of snow on top of what you see here. And to think I was afraid to leave the car in the barn for fear of collaps. In these two storms I measured a total of 58 inches in my driveway. No where to put the stuff after a while. It really sucked.

By the way, The flat tops are trash, even without the duct tape, get rid of em.

Also, looking at the condition of your hoses, you had better check out the vapor lines in the back of the car. What I see there is almost exactly like what mine looked like when I got it last year. (73 240Z) The second time I filled her up the left side balancing hose just fell apart at the pump and dumped like 4 gallons on the gas station lot, not a goot feeling. There is a 1/2",5/8" and 3/4" line inside the cockpit that I will bet have never been touched. you need to check them out!

[5thhorsemann]

well ok the temp meter isn't going higher then 60 degrees celsius so that can be the hose problem. Another point to look for.

when i bought the car the seller gave me an extra set of carbs which came from a 240z he said.

Will those fitt my 260 and is it better to use them instead of the original carbs?

Ask Ztherapy directly, send him pics as well, are the manifolds included?

[Robin260z]

D

By the way, The flat tops are trash, even without the duct tape, get rid of em.

Also, looking at the condition of your hoses, you had better check out the vapor lines in the back of the car. What I see there is almost exactly like what mine looked like when I got it last year. (73 240Z) The second time I filled her up the left side balancing hose just fell apart at the pump and dumped like 4 gallons on the gas station lot, not a goot feeling. There is a 1/2",5/8" and 3/4" line inside the cockpit that I will bet have never been touched. you need to check them out!

it can be possible. do these lines go underneath the drivers seat under the carpet?

I got some 240z carbs. will those fit or are these the same ?