Float level spec info

[simonknee]

Hi all,

Has anybody else noticed that documents on quite a few websites have the following information as to measuring float height in the main jet well (using the vernier technique).

dcoe spec = 1.14inch (29mm + 4.5mm)

Does anybody know or have a theory as to what the two values in mm refer to and why? 1.14"=29mm so what's the 4.5mm about. Try doing the sum for yourself. 29mm+4.5mm = 33.5mm = 1.32inches.

None of the web pages that quote this explain what the sum means or what the mm values refer to.

[carrierdave]

Hi Simon is this something to do with the leaking rear carb you were discussing in the other post? I too had an issue with excessive fuel spilling out of the carb on cylinders 3&4. This was also combined with carb spitting back.

I blocked off all suction ports from the manifold and increased the idle jets to stop the spitting which also appears to have almost eliminated the fuel spillage - not sure if they are linked?

Dave

[simonknee]

Kinda, I've been on a short and productive Weber odyssey!

Fuel leak was float far to high and fuel spilling into the barrel.
Also found that the pump jets needed a little extra tighten to get the new alu washer to seat.
Added a 1.5 psi reg to my new facet pump.
Reset the floats, as per manual, with 8.5mm drill bit.
Checked with a vernier and found this results in a 29mm level in the main jet well.
Still some weep into airbox.
Started following the methods of Keith Franck over on sidedraft_central.
Added an extra spring to the aux venturi and a seal around the trumpets.
No more weeping.
Then I got serious.
Checked for air leaks - found none.
Bought an STE Syncrometer and threw away the Gunson crap.
Barrel 4 was underperforming airflow wise at idle.
Drilled 1mm hole in butterfly to correct.
All barrels now flow identically through the revs.
Idle is amazing. No more dur-dum-dur-dum-dur dum. Even the better half noticed.
An off-idle stumble was cured by fettling the idle mixture screws.
You set at 1000rpm with the max rpm technique then check again at 1300rpm to ensure the jets are right.
This too is as per the manual my stock jets seem perfect.
A 2000rpm stumble (for which I believe the SE engine is infamous) was simply cured by raisin the float level.
Keith's recommendation is 25mm in the main jet well.
I achieved his by using a 5mm drill bit instead.

Most of the above is as per the Weber manual including drilling holes in butterflies.
However without Keith's assurance I probably wouldn't have done this.
And getting the airflow correct was absolutely key to a great performance.
Then the 25mm setting is pure genius and sorts out the lean spot.

As of this morning I have the most tractable engine ever.
From 700rpm to 3000rpm it will pull cleanly in any gear at any throttle.
OK ok, fourth at 700rpm is a bit silly and I can't WOT yet as I only have 600 miles on my engine.
However the drive across town to work put the biggest smile on my face.
No flat spots, no stumble, (a couple of spits but I can live with that).
This is stock jetting in 40DCOE18 on a "new" SE engine.
I think it will only get better when I invest in an AFR meter.

So WTF does: dcoe spec = 1.14inch (29mm + 4.5mm) mean???

None of these values have anything to do with a great running SE!