1972 Float Adjustment ...

[siteunseen]

1 hour ago, jalexquijano said:

So i should take both floats out and verify they are set to .55 gap install them and then set the 23mm with clear tube hose on front and rear carb?

Yes.  That's easiest way to get initial float level for me.  Glue the cork gaskets onto the lids and only use two screws while taking them off and on.  You will get it right after 2 or 3 attempts.  Don't rush this, wait until you have plenty of time.

Hold them right side up and blow through fuel bung while pushing the float upwards.  Have something that is .55" wide and hold it against the bottom of the lid. When you are at .55" you should not be able blow any air.  Valve is closed.

Fine tune with the mixture knobs

[jalexquijano]

9 minutes ago, siteunseen said:

Yes.  That's easiest way to get initial float level for me.  Glue the cork gaskets onto the lids and only use two screws while taking them off and on.  You will get it right after 2 or 3 attempts.  Don't rush this, wait until you have plenty of time.

Hold them right side up and blow through fuel bung while pushing the float upwards.  Have something that is .55" wide and hold it against the bottom of the lid. When you are at .55" you should not be able blow any air.  Valve is closed.

Fine tune with the mixture knobs

This means its .55 gap between the  rim of the lid and the bottom of the float depressed?

[siteunseen]

.55" from the underside of the lid and the top front of the float, pushed up.  You shouldn't be able to blow any air through the valve.

Think about the float in your toilet.  .55" from the lid to the top of the toilet's float with it full of water. When the tank float get to a certain level the water quits entering the tank.  Your tank isn't filling up enough now so when you flush you still have caca in the seat.

[jalexquijano]

Okay this means the float metal bracket just touching the pin of the needle valve and not pushing it?

[siteunseen]

No, no.  The pin or needle on the valve rides on the hump of the metal bracket on the float. The lower the float the longer the pin the more fuel flows in. When the bowl is full of fuel it "floats" the float pushing the pin in; shorter.  Shuts the valve, no fuel enters.

If I had time and patience I could photograph the workings of the float with the needle valve BUT YOU HAVE A DVD THAT EXPLAINS IT ALL.  Please watch it, in slow motion if need be.

I watched it 3 times before I ever turned a screw to rebuild mine. It's all right in front of you, you've got tunnel vision. Nothing you buy will make this simple, it's a tedious task that takes time. You have to get the baseline measurement first, either the clear tube (cheaper) or the sight glasses (not so cheap).

Think this through, write down a plan and stick to it. You are bouncing all over this simple but very important task. Focus on the plan.

To fix a running toilet you simply bend the rod going to the float. Same thing with your carbs. 

Watch the DVD please. I'm getting bored repeating myself. If I want to do that I'll get a girl over here. At least I eat good and get a cold sore.

[jalexquijano]

1 hour ago, siteunseen said:

No, no.  The pin or needle on the valve rides on the hump of the metal bracket on the float. The lower the float the longer the pin the more fuel flows in. When the bowl is full of fuel it "floats" the float pushing the pin in; shorter.  Shuts the valve, no fuel enters.

If I had time and patience I could photograph the workings of the float with the needle valve BUT YOU HAVE A DVD THAT EXPLAINS IT ALL.  Please watch it, in slow motion if need be.

I watched it 3 times before I ever turned a screw to rebuild mine. It's all right in front of you, you've got tunnel vision. Nothing you buy will make this simple, it's a tedious task that takes time. You have to get the baseline measurement first, either the clear tube (cheaper) or the sight glasses (not so cheap).

Think this through, write down a plan and stick to it. You are bouncing all over this simple but very important task. Focus on the plan.

To fix a running toilet you simply bend the rod going to the float. Same thing with your carbs. 

Watch the DVD please. I'm getting bored repeating myself. If I want to do that I'll get a girl over here. At least I eat good and get a cold sore.

Thats what i meant the measurement of the 0.55 inch gap is taken with the bracket just on top of the pin and not depressing it. You need to be clear. The dvd is not clear and asidea from that it refers to grose jets and not needle valve.

[gundee]

7 hours ago, jalexquijano said:

Okay this means the float metal bracket just touching the pin of the needle valve and not pushing it?

The way I read the 72 FSM, yes, that would be the correct setting. Then you can set the mixture as needed.

[Stanley]

It's been said before, but Nissan changed the later SU's, with longer ears for the float pin and a longer float valve in the front carb to make it easier to get the fuel level lower in the front bowl than the rear. It needs to be like that to get the same fuel level in both nozzles, due to tilt of the engine. Otherwise the front float has to be bent to get the same effect. Not good since a float that sits crooked is more apt to stick against the side of the bowl. A correct adjustment can still be made on the earlier carbs I expect, maybe a little more difficult.

If you have the later carbs with the long ears on the front one, and drill them to get them the same as the rear, you're slipping into darkness.

Maybe the sightglass, or the "same fuel level in the nozzles" methods are the easiest and most reliable. The Ztherapy video also mentions putting a washer under the valve. For fine tuning maybe the valve could be loosened or tightened slightly.

If there's a way to install a captive screw on the tang to move it relative to the float, that would make adjustment easier. A tiny change in the tang position makes a larger change in fuel level. At least when it's about right the job is done. Until you decide to mess with it again.

[siteunseen]

12 hours ago, jalexquijano said:

 You need to be clear. 

Okay, this will NEVER work...

Here's the .55" gap you keep asking about.  I found this from the DVD, Ray Charles could have figured it out.

This must be set with the lids right side up.  The weight of the float cannot be supported by the needle valve.  That's why the tang looks like a  ramp in the first photo.

It should look like  these, a hump not a ramp.  All cleared up now, moving on.  

 

 

 

Edited February 14, 2018 by siteunseen

[jalexquijano]

8 hours ago, Lumens said:

The way I read the 72 FSM, yes, that would be the correct setting. Then you can set the mixture as needed.

Ill need to check on that as i am still confused if the .55 inch gap is taken with the pin of the needle unpressed or slightly pressing the pin.

[gundee]

You have gone this far and spent a lot of money with poor results.

I would absolutely install a NEW pair of floats.

[David F]

On 2/13/2018 at 8:26 AM, jalexquijano said:

I still dont understand why the mechanic dialed the front carb mixture knob to 4 turns clockwise and the rear one to 2.5 turns clockwise. I took some pictures yesterday of plugs 1 and 3 of the front carb. Something must be wrong on that front float.

Do you need to crank the engine In order to verify the level with the sight clear tube fasten to the drain plug?? 

 

Don't just crank it, start it up and let her run.  Since you are using the drain plug for the clear tubing, I would put a loop in the tubing so you can hold it right up against the float bowl.  Liquid seeks its own level, so the loop wont make any difference.   Also, I purchased carb rebuild kits not too long ago...maybe 6 months and it came with a long and short float valve...so not sure why people are saying you cannot get them any longer.  I think the photo (just above) of the float horizontal with the lid inverted is going to result in a very low fuel level in the bowl.  For me, the floats come very close to hitting the top of the lid.