Fitment questions?
Call (855) 786-7101 or text (801) 304-3141.
Real people. Real answers.
Product details
The EMPI 43-5303-0 is a 1.20 main jet for 40/44 HPMX, 40/44/48 IDF, EPC 48/51, 48 IDA, and DCO/DCOE carburetors, setting how much fuel the main circuit delivers from the midrange to full throttle. EMPI's series for these carbs runs from 1.10 to 2.10 in 0.05 steps (Weber reference series 73401), so the 1.20 sits near the lean end. For scale, EMPI's 40mm dual HPMX ships with 130 mains, two full steps richer. Each barrel has its own main jet, so dual two-barrel carbs need four.
A jet this small usually goes on a smaller engine wearing large carburetors, or on a car that lives at altitude, where thinner air richens the mixture. Tuners usually reach it after a 1.25 still runs rich. EMPI's matching air correction jets for these carbs run from 1.00 to 2.20 (43-5401 through 43-5425).
Technical Details
- Manufacturer: EMPI
- Manufacturer part number: 43-5303-0
- Jet type: main jet
- Size: 1.20 mm
- Carburetors: 40/44 HPMX, 40/44/48 IDF, EPC 48/51, 48 IDA, and DCO/DCOE
- Sold as: each
Fitment & Compatibility
EMPI catalogs this jet for the carburetors above. Weber DGV, DFV, and ICT carbs and EMPI's EPC 32/36, 34, and 38 take a different series (43-5322 through 43-5342), and Kadron-style carbs use Solex-pattern jets.
Installation & Tuning Notes
Too small a main jet causes popping or misfire under load, and too large causes a bog at higher rpm. Test at steady rpm in a higher gear.
Common Questions
Which size main jet should I start with?
Start from the jetting your carburetor shipped with, then move one 0.05 step at a time. Go larger if it pops under load, smaller if it bogs or fouls plugs.
How many 1.20 jets do I need?
One per barrel, so two for a single two-barrel carb and four for a dual setup.
