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jetting for Dellorto carbs at 7000 ft. elevation ?

1K views 2 replies 3 participants last post by  alfettaparts2 
#1 ·
I have recently acquired a 1972 Giulia Super 1300 with Dellorto DHLA 40 carbs that originally came from Catania, Sicily. I live and drive 95% of the time at 7000 ft (2133 meters) elevation with occasional runs up to 10,000 ft., and down to 5500 ft.
The 1300 motor is completely stock AFAIK in terms of cams, compression, etc.
The current jetting I have identified is as follows:

Main jet- #110
Emulsion tube- #7772.5
Idle jet holder (?)- #7850.1
Idle jet- #48
Pump jet holder (?)- #7482.1
Pump jet- #70
other jet- #33
Not sure of the correct terms for these parts, so hope this is enough for anyone to make an informed suggestion of what and how much to change.
Car cranks and runs...OK, but surges at steady state cruise, and is hard to set idle speed to a repeatable level- seems to vary considerably with engine temp from cold to fully warmed up. Some of this could be due to my not having access to a manometer, but I think it's pretty close.
Suggestions welcome as well as helpful links, websites, etc. TIA.
 
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#2 ·
I just read that Telluride CO, at 8750 ft., has 15% less air density than sea level. So you'd be a bit less than that, 10-12%? Go down 10% on main jets? That's a crude start. I don't know how available Dell'Orto jets are compared to Weber.
I'd think a 10% change in idle mixture could be handled by adjusting the screws.
Andrew
 
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