Indmar Marine Lower Intake Manifold – 5.7L PFI E-Coat | Part #531197E
Restore peak engine performance with this genuine Indmar lower intake manifold for the 5.7L Port Fuel Injection (PFI) engine, featuring a durable E-coat (electrocoat) finish for superior corrosion protection in the demanding marine environment. The lower intake manifold is one of the most significant components on your engine — directing the air/fuel mixture from the throttle body into each cylinder for combustion.
Compatible with: Indmar 5.7L PFI (Port Fuel Injection) marine engines fitted to Malibu, Moomba, Supra, and Tige boats. Contact us to verify fitment for your specific model year before ordering.
What is Port Fuel Injection (PFI)?
Port Fuel Injection delivers fuel directly into the intake port of each cylinder — just upstream of the intake valve. This provides:
- Precise fuel metering for optimal combustion efficiency
- Better atomisation of fuel for cleaner, more complete burning
- Improved power output and throttle response
- Reduced emissions compared to carburetted systems
- Compatibility with the MEFI engine management system
The lower intake manifold is the foundation of the PFI system — it must maintain perfect sealing and flow characteristics to ensure each cylinder receives an equal and correct air/fuel charge.
What is E-Coat and why does it matter?
E-coating (electrocoating) is an advanced corrosion protection process where a uniform coating is applied using an electrical current — the same process used in high-end automotive manufacturing. On a marine intake manifold the E-coat provides:
- Uniform coverage of every internal and external surface
- Superior resistance to moisture, coolant, and fuel exposure
- Prevention of internal corrosion that can contaminate the fuel system
- Longer service life compared to uncoated or standard painted manifolds
- A clean internal surface that maintains optimal fuel flow characteristics
In the harsh marine environment where condensation, humidity, and coolant exposure are constant — E-coat protection is not just a nice feature, it's essential for long term reliability.
When should you replace your lower intake manifold?
The lower intake manifold is a long-life component but may need replacement if you notice:
- Severe internal corrosion or pitting affecting fuel delivery
- Cracks or warping at the gasket sealing surfaces
- Physical damage from impact or overtightening
- Coolant contamination inside the manifold passages
- Persistent vacuum leaks that cannot be resolved with new gaskets
- Major engine rebuild or overhaul requiring manifold replacement
Pro tip: Whenever you remove or replace your lower intake manifold always replace the intake manifold gaskets at the same time — part #556099 (order 2 per engine). A new manifold with reused gaskets is a false economy — old gaskets on a new sealing surface will not provide the correct seal and will likely leak. Always start with fresh gaskets on a new manifold.
Features:
- Genuine Indmar OEM part
- Designed specifically for Indmar 5.7L PFI marine engines
- Durable E-coat (electrocoat) corrosion resistant finish
- Optimised internal passages for equal cylinder fuel distribution
- Precision machined gasket sealing surfaces
- Compatible with MEFI engine management system
- Direct replacement — no modifications needed
Part Number: 531197E
In stock and shipped fast from Australia 🇦🇺
