Cold Start Removal Kit for IDF, Choke Block Off

OVERVIEW

Precision performance and absolute reliability are the hallmarks of a well-tuned air-cooled engine, and the EMPI Cold Start Removal Kit for IDF and HPMX carburetors is an essential upgrade for any serious VW enthusiast. On a standard Weber IDF or EMPI HPMX series carburetor, the cold start enrichment circuitoften referred to as the chokeis a complex mechanical assembly that is frequently unnecessary in performance applications. For off-road racers, sand rail pilots, and Baja Bug owners, this mechanism represents a significant liability. The factory choke housing is not perfectly sealed against the extreme silt and fine dust found in the desert or on the dunes. By installing this block-off kit, you effectively eliminate a primary point of entry for contaminants that can score your cylinders and clog your internal jets, ensuring your engine breathes only through your filtered intake.

Beyond the protection from environmental debris, the EMPI 1096-50 kit simplifies your carburetor synchronization and tuning process. Many tuners find that the internal starter valves in the IDF circuit can develop minor vacuum leaks over time as the internal springs and plungers wear or become gummed up with modern fuel additives. This kit replaces the bulky external housing with a sleek, low-profile block-off plate that provides a permanent, airtight seal. Whether you are running a high-compression Type 1 street sleeper or a rugged Type 4 powered transporter, removing the cold start circuit streamlines the carburetor body and removes the risk of the enrichment circuit accidentally engaging during high-vibration off-road use. It is a small investment that pays massive dividends in long-term engine health and idle stability.

FITMENT

• Weber Carburetors: 40 IDF, 44 IDF, and 48 IDF Series.
• EMPI Carburetors: 40 HPMX, 44 HPMX, and 48 HPMX Series.
• VW Type 1: Beetle, Karmann Ghia, and Thing (equipped with dual IDF/HPMX setups).
• VW Type 2: Bus, Kombi, and Transporter (1950-1979 models with performance upgrades).
• VW Type 3: Squareback, Fastback, and Notchback.
• VW Type 4: 1700cc, 1800cc, and 2000cc engines.
• Custom Applications: Sand Rails, Dune Buggies, and Trikes utilizing IDF-style induction.

SPECS

• Part Number: 1096-50.
• Material: High-grade stamped steel with corrosion-resistant plating.
• Component Count: Includes block-off plate, sealing gasket, and necessary mounting hardware.
• Function: Replaces the enrichment (choke) starter valve assembly.
• Configuration: Sold individually (two kits required for a dual-carburetor engine).
• Installation: Bolt-on design requiring no machining or permanent modifications to the carburetor body.
• Origin: EMPI Engineered for high-performance air-cooled Volkswagen applications.

PRO TIPS

1. Complete Internal Component Removal

When installing the EMPI Cold Start Removal Kit, it is absolutely critical that you remove all the internal components of the enrichment circuit before bolting on the block-off plate. This includes the starter valve plunger, the return spring, and the guide. If you simply bolt the plate over the existing mechanism, you run the risk of the plunger being held in an "open" or "partially open" position, which will cause your engine to run excessively rich and ruin your spark plugs. Always ensure the internal cavity is empty and clean before applying the gasket and plate for a true vacuum-tight seal.

2. Surface Preparation for a Perfect Seal

Before installing the new gasket and block-off plate, take the time to inspect the mating surface on the back of the carburetor body. Over years of heat cycles, these surfaces can accumulate old gasket residue or minor oxidation. Use a lint-free cloth and a mild carburetor cleaner to wipe the area down. If there are stubborn deposits, very gently use a plastic scraper to remove them. Ensuring a perfectly flat and clean surface prevents vacuum leaks that could cause an erratic idle or a lean condition in that specific barrel of the carburetor.

3. Adjusting Your Cold Start Routine

Since you are removing the mechanical enrichment circuit, your engine will no longer have a "choke" to assist with cold morning fires. To start an engine equipped with these block-offs, simply give the accelerator pedal two or three firm pumps before turning the key. This utilizes the accelerator pumps to squirt a small amount of raw fuel into the intake manifolds, providing the necessary enrichment for the engine to catch. Once the engine starts, you may need to hold the throttle open slightly for 30 to 60 seconds until the cylinder heads gain enough heat to sustain a smooth idle. This is a standard practice for performance VW engines and is much safer for the engine than relying on a leaky factory choke.