Weber jetting issues
 

Here's the scoop. OER 45, had 40mm chokes and 170 main / 160 air jets with f11 Etube. Ran good, had power, got decent gas mileage. Problem was, holding at cruise it sort of puttered and coughed. Not badly but you can tell it was there. I thought it was a choke problem, so I got some 36 chokes. Talked to another forum member on here running the same setup and he ran 36's as well if I remember correctly. Slid those in, dropped the main jets down to 160 and airs to 150. Put the chokes in and it ran a little different than the 40's, but when I got on the highway, it would buck and kick horribly when cruising. I had to get on the gas, then let off then back on etc. Got home and the next day just said #$%& it. Took the chokes out and now running a straight 45, no choke. Replaced the jets with 170main and 160air and took her out for a ride.


Drove great! The sputtering and bucking/kicking are almost nil! Floored it a few times, and it feels like the car has no balls under 3.5k... To the point where I let the clutch out a little too fast @2k and stalled it. Changed the main jets to 175 and that helped a little. I don't want to keep going higher with the main jets hoping that more fuel will bring my car to life and get some power behind it. I have F9 E tubes, tons of main jets, and lower air jets. 160 is the highest air jet I have besides 220.

So, questions are, am I heading in the right direction with putting bigger main jets in? I dont want to end up just pouring fuel in it.

Would F9 Etubes run leaner or richer through the band than F11's? And if anyone has ideal/ball park jetting, that would be great.

I have done searching and it is mostly scattered info...

Crusing speed (below 3K RPM) is controlled by the "Idle Jets", not "Main Jet". Surging of some sort or not holding a steady cruise is common caused by too large of an idle jet. So try using a 1 step down (they come 5* increments).

Thanks wacky! I forgot you are the weber guru here. I will go try that. If that cures the surging and whatnot, what do I do about the lack of power down there? It never stalled on me like this when I had the 40 chokes. I am trying to find out what Etubes do what, but all I can find are Nissan Z forums...

Stu, get a copy of this book.

Pm me and I can help you out some.

I have a copy of some book like that, but it is printed out on paper. I am gonna go mess around with the idle jets and see if I can slim it down a little more.

PM if you need to see it.

Down to 60F9's and the Idle is better. Still have the driving issue. When redlining in 2nd and shifting to third, it has a hesitation then picks up somewhat. I am thinking of putting in my F9 tubes in there with the 175 main and 160 air jets to see if that helps.

TG: I just checked out my printout, and it is that exact book! I will go reading through it in a minute. That will probably help out tons.

Take a look at this article. Might help you out. Lot of resources mentioned in it at the end.

Put in 60F9's and I can run the mix screws all the way to the bottom and the engine still runs.

I cant give it gas too fast, and when I give it gas it is slow. This car is irritating the living $%&# out of me, and I am seriously debating on selling it.

The P.O. of the manifold neglected to tell me he ported the hell out of it and it looks like it can run a 48 or even a 51 no problem. Is this my problem to the stumbling and horrible carburetor issues?

[QUOTE=Jeezus;7439657]
Put in 60F9's and I can run the mix screws all the way to the bottom and the engine still runs.

QUOTE]



sign that your idle jet is too big. Try next smaller size. Typically, it has to be less than 1 full turn. If it continues to run once "fully seated", it is too big.

the only size lower than 60F9's are 65F8's and it bottoms out as well. Now I have 55F7's in there and I have to pull it almost all the way out to get it running. Is tehre a good size jet that I can buy that will let me idle lower than 2k and not put put? This carburetor is costing me 700$ and it is really pissing me off.

And not to mention that some mother$%#&er decided to leave a FOOT LONG SCRAPE on my drivers fender.