Okay, help with my motor, was: "carb dial in help? (webber IDF 44)" Options

[VaccaRabite]

*edit* Note, cylinder bank 3/4 is not firing. Plugs are oil fouled. All four cylinders have decent compression, considering that the rings probably are not set yet. Carbs are fresh rebuilt, I have yet to check spark.*/edit*

I have set my idle at 1K rpm.
Idle adjustment screws for the 3/4 bank is almost all the way out.
Idle adjustment screw for 1/2 bank several turns in.

Both carbs are idling at 5 kg/h according to my flow meter.

Mix screws for all 4 carbs are 2.5 turns open.

When I open the throttle to ~3K rpm, the 3/4 bank only sucks slightly more air. The 1/2 bank jumps up to about 15 kg/h.

So, where am I off.

I have my weber tech manual too, but thought I would ask here to see if I got a faster "ah-ha" type answer (like usual).

[iamchappy]

Over the years i found that for some reason i found the best tune i could get out of a carb set up was by ear.
With the unisyn even when i had them all matched, the engine didn't run as well as when i used a length of rubber hose and matched the hiss of each carb intake to all sound the same. If you can tune a guitar you can do this.

[Joe Bob]

No but I CAN Tuna Fish....

[Jake Raby]

Al, go ahead and bolt on the Chinese carbs and that problem will go away :-)

Damn thats a hard thing to say!

[VaccaRabite]

Okay, so I got a break in the weather and ran out to do some tuning.

I took some pictures for Jake. His guess is that my vents are 34mm.
(IMG:http://farm4.static.flickr.com/3148/2642903679_3dfcbc4d84.jpg)

I took the carb off the manifold and inspected the venturi closely, but could find no marking, so it must be engraved on the under side (which at the moment I can not get to).

I put everything back together and started really examining the linkage. I noticed that the geometry from the pushrod that worked the throttle was steeper on the 1/2 bank then the 3/4 bank - seemingly by design. I am guessing this is why the 1/2 bank is doing most of the work.

So, I mounted the 3/4 pushrod farther back on the linkage arm. I also turned the turn buckle to lengthen the arm a little. Then I powered up the system, and let the fuel pump run for a few moment to refill the float bowl on the carb that I had pulled off.

Suddenly I smelled gas. I must have bent the float arm a little, as the 1/2 carb was overflowing with fuel. *DAMMIT* I sopped up as much as I could, and took the carb apart. Reset the float to 10mm to closed.

Not knowing what to do about the gas sitting in the intake manifold, and not having a baster to suck it out, I ran the starter without fuel or spark and pumped it out. I suppose I need to remove my exhaust and drain that fuel out before I blow mu muffler off. I'll have to do that tomorrow.

I'll test to make sure that my carb float shuts off as it is supposed to first though.

I do not think that these carbs have choke circuits, but thats something that I will look for tomorrow.

Zach

[craig downs]

Your carbs have the choke circuit as I can see the jet and the brass valve for it at the top of your pic. Just remove the cover that has a lever on it or some have a block off plate thats in the middle of the carb facing the engine. Look inside and you can see the 2 brass valves and make sure they are all the way down and seated and that they can move freely in the bores.

[ArtechnikA]

Your carbs have the choke circuit as I can see the jet and the brass valve for it at the top of your pic.

looks like accellerator pump parts to me ...