Fuelab 52503-5-L-L 525 Series Adjustable Carbureted Fuel Pressure Regulator In-Line Large Seat Gold

The Fuelab 525 Series 52503-5-L-L is an adjustable, in-line fuel pressure regulator engineered for carbureted applications requiring precise, low-pressure fuel delivery. Built from billet aluminum with military-spec MIL-A-8625 Type II gold anodizing, this regulator delivers lasting corrosion resistance and a distinctive appearance under the hood.

Designed with installation flexibility in mind, the 525 Series positions its -6AN return port in-line with the -6AN inlet port — not on the bottom — making it ideal for use in tight engine bay locations where a bottom-exit return line would be impractical. The regulator accepts both port-style and non-port-style union fittings without interference, offering broad plumbing compatibility.

Compatible with gasoline, diesel, methanol, and ethanol, this unit covers a carbureted pressure adjustment range of 1–3 PSID with a large seat design rated for up to 1.25 GPM (280 LPH) at 3 PSID. A fine-thread adjustment screw provides smooth, repeatable pressure tuning, while a jam nut locks in the setting securely.

Key Features:

• Pressure adjustment range: 1–3 PSID — optimized for carbureted applications
• -6AN inlet and -6AN return port — both in-line for tight-space installation
• Large seat design — maximum flow capacity of 1.25 GPM (280 LPH) at 3 PSID
• Regulation slope: 0.7 PSI/GPM for stable fuel delivery
• Compatible with gasoline, diesel, methanol, and ethanol
• Billet aluminum body with gold anodize per MIL-A-8625, Type II
• Fine-thread pitch adjustment screw for precise pressure setting
• Includes 1/8 NPT gauge port with plug for an external pressure gauge
• Includes 1/8 NPT pressure reference port with barbed fitting for blow-through boosted carb applications
• Versatile mounting bracket with stainless steel hardware included
• CARB-exempt (EO number applies — for racing/off-road use)
• Backed by Fuelab's 2-year limited warranty

The 52503-5-L-L ships complete with the regulator body, barbed fitting, plug, flat washer, jam nut, O-rings, and mounting bracket hardware — everything needed for a clean, professional installation.