Tuning 40 DCOE Weber 151 on an L24

[conedodger]

Well, I'm doing it. I found a guy in England who is restoring a Maserati 3500 which uses a pair of 42DCOE 8, which I have three of. We agreed on a price that will give him three of his original carburetors and will get me three brand new 45DCOE 152's. So my tuning will begin anew. I would imagine, I can just transfer over the jetting I have and if my chokes (32mm) are the same, I should be running pretty close to the same.

[LeonV]

Well, I'm doing it. I found a guy in England who is restoring a Maserati 3500 which uses a pair of 42DCOE 8, which I have three of. We agreed on a price that will give him three of his original carburetors and will get me three brand new 45DCOE 152's. So my tuning will begin anew. I would imagine, I can just transfer over the jetting I have and if my chokes (32mm) are the same, I should be running pretty close to the same.

Nice, Rob! Keep us updated.

[Lazeum]

Not sure about the equivalence of choke size with different carb sizes.

Check the file attached below, given by Duragg on HBZ.

The only exception would be at 32mm according to this chart so your comment may still apply

[240260280z]

Great data Matt! Thanks

[Reverend]

Lucky bastard...

We finally dipped under $4/gal recently.

Lucky indeed...8.5$ dollar per gallon here...

[LeonV]

Last week, I replaced the custom 100 air jets from the O3 etube with 140s. This flatlined my AFR trace at WOT! No more getting richer as rpms climb. This did make low-rpm transition a bit leaner but I'll be tuning that out with the hypojets, which control low-speed, low-throttle opening operation.

Next plan:

- Smaller hypojets, either the H20 or H18 should do the trick.

- Drilling out my pump jets to .62mm, I still need a slightly fatter shot when I get on it. By optimizing (leaning out, in my case) all the other circuits in the carburetor, the pump shot needs to do more work to keep the mixture proper now that everything isn't masked by running overly rich..

- Re-sync and re-tune idle

[240260280z]

Idle Mixture Screw Pitch on 40DCOE2 is 0.8mm

I'll measure it on the 40DCOE151's when I get close to them(100km away presently)

The other important part to measure is the taper of the screw. I'll measure that optically.

For the record the 40DCOE151's thread is also 0.8mm. I'll measure the taper.

[TewFodyZee]

Where are you sourcing (for purchase) the Keith Frank optical float gauge?

[240260280z]

Where are you sourcing (for purchase) the Keith Frank optical float gauge?

Optical Fuel Level Measuring Tool Indexed at 25mm for DCOEs - Buy @ Webstore item#30564448

[TewFodyZee]

Oh, there she is. Thanks for the link.

So I'm new to the tuning of Weber carbs, actually just bought a set of triple 40 dcoe with Cannon manifold. I just happened to catch a episode of Wheeler Dealers where they tuned a carb'd Lambo with this at idle to match airflow:

Air Flow Meter Synchrometer - Dune Buggy Parts, Sandrail Parts, VW Parts - MooreParts.com

Has anyone used this unit or similar?

[240260280z]

Here is another: http://www.classiczcars.com/forums/carburetors-s30/50040-sk-racing-carbs-2.html#post440903

[chuck r]

I just want to thank you guys for posting all this great info.

Just finished the resto on my series 1 and after a shake out drive this weekend discovered the notorious flat spot at about 2200-2500rpm. I'd set the floats to 8.5mm but know the actual fuel level is about 32-34mm below the jet well surface.

Btw, my carbs are 40DCOE-18's.

This thread gives me hope that the fuel level is the main culprit. Now if I can just stay clear-headed while digesting all the data!