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Product details
The EMPI 43-5515-0 is a .57 idle jet for EMPI 40/44 HPMX and Weber 40/44/48 IDF and DCNF carburetors that meters fuel for the idle mixture screw and the progression circuit. In EMPI's series the .57 sits one step above the .55 and one below the .60.
Idle jet orifices are small, and a plugged jet causes poor running on its own, so clean the old jets before deciding a new size is needed. EMPI tackled clogging on its HPMX carbs with extended idle jet vent tubes, now fitted to new HPMX carbs and sold as the 44-1130 retrofit kit for one existing HPMX or IDF carb. Replace the idle jet O-ring (EMPI 43-6417) while the jets are out.
Technical Details
- Manufacturer: EMPI
- Manufacturer part number: 43-5515-0
- Size: .57
- Circuit: idle and progression
- Sold as: each
- UPC: 707924224139
Fitment & Compatibility
EMPI lists the .57 for its 40 and 44 HPMX carburetors and for Weber 40, 44, and 48 IDF and DCNF carburetors. EMPI sizes the 40mm HPMX for engines up to 2000cc and the 44mm for 2100cc and up. Weber IDA, DCOE, and DGV carbs use different idle jet series.
Installation & Tuning Notes
Set the mixture screws with a warm engine. If the engine wants them backed far out, the jet is still small, and if it idles smoothly with them barely open, the jet is too large.
Common Questions
Does the idle jet affect anything above idle?
Yes. It feeds the progression circuit, so it shapes the transition from idle onto the main jets.
Will a .57 fit my 44 HPMX?
Yes. EMPI lists it for the 40 and 44 HPMX. The dual 44mm carb ships with .55 idle jets, so the .57 is one step richer.
