All the info for this procedure you can find at the Z garage.
http://datsunzgarage.com/engine/

I thought i'd give it a do and see what i could find..
sorry if the pics come out small.. if you want larger pics let me know..

Here's the tube i used.. Its 5mm clear tube. I got it at the hardware store.


Disconnect the fuel line then attach clear tube. Use the clamp thats already there to keep it tight and to avoid leakage..



Make sure the hose is going over the carb to avoid the fuel levels being disrupted. Once you've done this disconnect the coil lead and crank the engine over a few times to make sure the fuel bowl is full. If you have electronic fuel pump just turn the ignition to ON for a few seconds..


Here's a pic of the measurment i took...



I scribed the line at 23mm..
Here's what i got. Its not perfectly accurate but at least it wasnt over flowing. I was hoping it was gonna be way out cos the cars running rich.. but at least now i know its probably not this...





At this point you could make a note of where the fuel level is in the tube then turn the engine over again for a few turns. This will tell you if the needle and seat r worn on the entrance to the float.. u should NOT get any difference in the amount of fuel. If the level keeps going up then the needle and seat r worn.. Just thought i'd add that.. just thought of it..

This was a piece of cake to do. So if you've got doubt's about your float level this takes about 10 minutes to find out if your in the ball park..
Its quite a genius idea really.. why didnt i think of that.. i use to do the turn float upside down and measure how far from the base it sits..

This way you can see exactly how much fuel is inside your float bowl.

Enjoy all... Thanx to the Z Garage......[/b]

Heres a pic of the carbs too...

I didn't invent the hose method, but I'm glad you found what your carbs were doing....one of those great "aha" moments. The old school method of turning the float lid over and measuring the height of the float actually gives very coarse measurements, I'm kind of amazed it has been used worldwide for so long.

The problem is that the metal hinges on the floats easily get distorted after 35 years of adjusting (did the previous owner know what he was doing when he rebuilt them 20 years ago?) And even if your car is unmolested, the heights may not have been correct from the factory to begin with. Actually sighting the fuel levels is about as accurate as you can get.

If you're feeling a bit adventuresome you should try turning down the mixture nut 10 turns to see the fuel height while looking down the tip of the fuel nozzle. This will get your fuel levels within a mm. This method made a significant difference on mine.

_________________
Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed

Yeah i gave that go too.. it looked to be pretty close.. i couldnt get decent pics of it though.. my flash was being a ford...hhehhehehehehehe
ford = thats Nissan for a swear word...heheheheheh

All round i was pretty happy with the level.. it wasnt perfectly accurate but close enough for now.. i was hoping to find it out by alot. The car is blowing black smoke and blue smoke.. It was smokey with the original engine so we put an L28 in it which was running nice in its previous car. But we're getting the same smoke. bit of blue bit of black. so our guess is that engine needs rebuild too... The mixture is about 1 and a half turns out. if we go to 1 turn out it wont rev under load.

My guess is that the carbs need new needle and seat. Theres nothing else that can wear????? The fuel only comes into the carb in one spot. thats the needle...

Putting the L28 in should need a little more fuel.. maybe 2 turns out..
but she black smokey at 1 turn out...
The car had 2 previous owners and has been unmodified. except extractors. so im guessing the carbs have never been done..

Concentrate on the carb itself, the floatbowl and needle are just to set the fuel level available to the carb. The level is either wrong or right.

For smoking and idle problems try replacing the CARB fuel nozzles and needles together, it makes more difference than you think. For a L28 use .100 Ztherapy nozzles and N58/SM needles and you should be back on track.

I find that less than 2 turns down on a L28 is too lean, I'm at about 2 1/4.

Best rule on engine fuel mixture I ever heard:

- if it burps there's too much air.
- if it farts there's too much gas.

_________________
Bryan Little
Datsunzgarage.com

1970 240Z - enhanced F54 L28 w/P90, Weber DCOEs, 4:11 R200, Nissan T5 5-speed