what i am doing is pulling the choke for a minute while it warms up, closing it and then just drive slow until the engine warms up. After 6 to 7 minutes once it reaches half of the temp gauge i start driving normally and cruising at high speed and no problems whatsover. no backfire at the intake or at the exhaust even while realising the gas pedal at 2nd gear. Should i open the floats and close the gap even more? Am afraid i could leave the car too rich.

1 hour ago, jalexquijano said:

what i am doing is pulling the choke for a minute while it warms up, closing it and then just drive slow until the engine warms up. After 6 to 7 minutes once it reaches half of the temp gauge i start driving normally and cruising at high speed and no problems whatsover. no backfire at the intake or at the exhaust even while realising the gas pedal at 2nd gear. Should i open the floats and close the gap even more? Am afraid i could leave the car too rich.

Do not mess with the floats!!!!! The car is not too rich for sure! If it drives good, leave it for a while, drive it in traffic and see if your idle issue is gone in traffic. Once you put some miles on it then we will double check you have it fixed. It is getting close...

Unless Mark disagrees @Mark Maras

 @jalexquijano I agree with Patcon. Put some miles on it. At this point in time, don't go looking for problems. Should small problems arise, we'll deal with them at that time. Sounds to me like the carbs are finally close to optimum setting. Congratulations. You not only got it running good but you've learned a lot about SU's too. I like WIN - WIN situations. Now go drive it and tell us how much fun it is. 

Okay i will turn the idle mixture knob of the front carb to 3.75 turns clockwise and test the car. Now we need to deal with the engine bay heat that causes the plugs to turn black due to the amount of heat inside during long traffic idle times. What if i find a hose and connect it to the air filter box and plug the bottom entrance of the box so it can suck fresh air during idle? Do you think this can be a solution? At this time it only sucks hot air.

25 minutes ago, jalexquijano said:

Okay i will turn the idle mixture knob of the front carb to 3.75 turns clockwise and test the car. Now we need to deal with the engine bay heat that causes the plugs to turn black due to the amount of heat inside during long traffic idle times. What if i find a hose and connect it to the air filter box and plug the bottom entrance of the box so it can suck fresh air during idle? Do you think this can be a solution? At this time it only sucks hot air.

Someone can correct me if I'm wrong, but I don't think engine bay heat makes your plugs turn black.  The plug color is a byproduct of internal combustion.  Cooler air to the engine is always a plus, but I don't believe your approach is good.  I live in the desert where the air temp hits 120º and the stock air intake/preheat works nicely just as the Nissan engineers designed it to work almost 50 years ago.  As previously mentioned, stick with the current advice and don't start looking for other variables to fiddle with until carb adjustment is resolved.

Dennis

I do not run a heat riser hose on the air box.  I agree with Dennis. Heat in the engine bay has no effect on your plugs.

I'm thinking with the gasoline you have in Panama you need to figure out a hotter plug and gap, possibly?

I got my hands on a NOS set of float valves (longer & shorter for '72 240z) and it solved my problems with float bowl levels.  They're no longer available, so you need to hunt for them.

I bought a couple of these valves in amazon. Car is speeding nice. Problem is during idle in traffic jams.

I put the  front and back like the pre '72s SUs

Just like he OP had a Porsche mechanic do to his. He has no longer or shorter float  arms anymore. Both are they same length as per his past post.

Best thing I've done to my SUs. In my opinion.

Have you set them equally shitty by disabling the fronts and the rears?

Edited May 19, 20187 yr by siteunseen

You need a hotter plug or  tweaking on that petroni

 Damn it man I can't do $^!# now with my phone. 8^(

I have shorter and longer back again. Why do i need bp5es (hotter ) instead of bp6es?

You have funky fuel down there from what I've read.  Those plugs looked lean the last time you posted. Now you say they are sooted up? Confused once again. But hey, I'm not confused something'z wrong.