Weber help
 

I rebuilt and turbo prepped my 51 IDA Weber and attempted to start it. It did not feed any fuel. I am assuming at this point that it is my float setting.

Here's my current tune on my street ported 12a:

*Will eventually go blow through turbo

37mm chokes
3.2 Glass ball needle valve
60f10 idle jet
120 idle holder
195 main
150 air corrector
f-3 turbo e-tube


My question is, can I set my float height without removing the Weber? The way I set the height before involved hanging it upside down.

the top needs to come off to set the float level, but there is a hole on the top of the float chamber, so you can push the float down if you need too

Exactly. I only want to pull the top off to set my float level and keep the rest of the Weber bolted down. But I am not sure on how to set my float level with the carb on the motor. I usually set the float level by hanging the Weber upside down and setting the height.

How do I set it with it on the motor?

Found this. I'll post it here for future reference.

TheSamba.com :: View topic - Setting float level on Weber IDA carbs.

Ok, so I re-set my needle valve height. The float height. And the distance between the needle valve and the thing it touches on the float.

Originally, I did not get any fuel to the bowl at all. It was bone dry. After the new settings, the car still didn't get any fuel. So I pulled the top cover off again to check the bowl for fuel. This time I noticed about 1/8th to a 1/4 inch of fuel at the bottom of the bowl. This was after about 30 seconds to one minute of the fuel pump running.

Should the bowl fill up faster than this? I am not sure if this is a problem.

Should fill up in a few seconds. Plenty of fuel from the line with the pump on and the line unhooked?

Fuel level is VERY critical on Webers, triple check it.

Ok. Then I'm doing something wrong.

If I'm not filling the bowl fast enough, is that because I have my needle valve to low and my float to low shutting my fuel off? I have a theory on this. I think the measurements I set everything too are supposed to be used with a gasket. I have a very thin bead of silicone. I think maybe this is my problem...?



This is how I am setting my heights for everything. Maybe I am just doing it wrong...?

Needle valve: I am measuring from the surface it threads in to. To the tip of the ball at the end of it. Hanging it upside down (Stacks facing the ceiling). I adjust the height by adding washers. My end result is 25mm.

Float height: I measure from the surface where the gasket would sit to the top of the float body (Not the seam in the center). 5.5mm is what it is at. But the problem is, when I look down the center of the float, you can see that on either side of the seam where the float is joined together, that the sides are not even. Either side will give me a different height. I chose a side a set it to that.

Distance between needle valve and float: this one I set with the carb still on the motor. So it is NOT upside down. I am not sure if it is supposed to be. I set this by bending the little tab and measuring from where the gasket would sit. But since the tab is angled it is easy to get different measurements or be incorrect. I tried to set my caliper to the center each time. It was somewhat consistent. 24.2 mm is my goal.

i found that my glass ball needle valve was a different height from stock, so you can toss all the stock measurements out the window...

you want the float level as high as possible, without it dripping into the boosters with the pump on engine off.

It makes sense to me that the distance between the ball on the needle valve and the tab that depresses it on the float is the only important measurement.

So today I will try setting my float level as high as I can and only worry about the distance between the needle valve and the tab.

So, with the gasket being about 1 mm thick . The stock needle valve height at 25mm. And the tab on the float being 24.2mm down. That would make the distance .2mm between the needle valve and the tab.

Sound right?

you are not using the stock needle valve...

no need for any measurements, bend the tab until fuel reaches the top/fills up before spilling into the barrels, make sure you have desired fuel pressure before anything.

Yeah I think you're getting a bit too hung up on measurements when you've got a few variables from stock to deal with as it is.

On mine we just did what previous poster said, basically trial and error till it ran right.

Ok, I do get caught up in measurements. I admit that. It's a product of my career choice.


So how do I know fuel has reached the top of the bowl? I can't see in there with the top cover on.

re-read my previous post and follow each step:icon_tup:

I did. How do I know when it reaches that point of where it is about to spill over?

I should add that I can not see down my throats. I have a plenum welded directly to the velocity stacks. The stacks are sealed to the top of the Weber as well. So I can not remove the plenum without removing the top completely.

You will have to remove anything that's blocking your view from the barrels.

1. adjust fuel pressure to operating fuel pressure
2. adjust to right before spilling over
3. turn car on and make sure its not leaking when idling/revving

You're using a 51 IDA on a streetport 12a?!

There is still one major problem with only adjusting the float level. If that little tab is depressing the ball in the needle valve, it still not let any fuel flow into the bowl. So if that tab is bent up too high, it will let the fuel bowl get too low before letting more fuel in. And if the tab is bent too low, it will let fuel keep pouring in and flood the carb.

Everyone just says to raise the float level until just before it overflows. But that little tab on the float that depresses the needle valve, is really the key in having correct fuel flow to the bowl. Since this motor will be turbo, enough fuel in the bowl is extremely important.

I'm not saying that anybody is wrong, it clearly has worked for others. I just don't see how raising the float level itself without setting the distance between the tab and the needle valve works properly.

Finally got it set. It needs some adjustment still. But at least it fills the bowl and the car will run.

I'm sure I'll have some tuning questions. I'll make a separate thread for that.

What he said

I feel a 51 might be overkill for a streetport.

It is overkill. I ran a 51 on a 13-B Sp years ago. Had to use smaller venturies, so start with 38. Iirc, i used a 40mm and larger idle jets to eliminate the bog. I switched to a 48 IDA several months later

Guys he's going turbo so the 51 should be fine.

But it is pointless if he cant fix the bog

I had this 51ida running great on a very similar 12a street port. The best part about a Weber is the ability to change the chokes out.

51ida is overkill for a 12a street port. But it will be much better than a 48ida when I go turbo. Which is already half way done.