Ignition Tune-Up Kit – Fits MerCruiser V8 Engines with Mallory Ignition (Replaces 391-5090Q1)
Ignition Tune-Up Kit – Fits MerCruiser V8 Engines with Mallory Ignition (Replaces 391-5090Q1) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Ignition Tune-Up Kit – Fits MerCruiser V8 Engines with Mallory Igni...
Product Details
This Ignition Tune-Up Kit – Fits MerCruiser V8 Engines with Mallory Ignition (Replaces 391-5090Q1) is designed for Ford and GM-based MerCruiser V8 engines equipped with Mallory conventional ignition systems. It provides all the essential components to restore spark performance and reliability.
It serves as a direct interchange for Mercury part numbers 391-5090Q1, 898253004, 8M6001250, S18-5251, and 371-175.
- Engineered as a direct replacement for your original components.
- Includes a six-piece kit containing a condenser, points, and rotor.
- Designed to resist RFI interference with sensitive onboard electronics.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 391-5090Q1 |
| Mercury | 898253004 |
| Mercury | 8M6001250 |
| Mercury | S18-5251 |
| Mercury | 371-175 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is specifically designed for MerCruiser models running Mallory conventional ignition systems.
| Brand | Model | OEM Part No. | Notes |
|---|---|---|---|
| MerCruiser | V8 engines with Mallory Conventional Ignition | 391-5090Q1 | Ford and GM-based engines |
Technical Specs
- Product Type
- Ignition Tune-Up Kit
- Installation
- Direct replacement
- Fuel Type
- Gasoline
- Dimensions
- 181.1 × 152.4 × 25.4 mm (7.13 × 6.0 × 1.0 in)
- Weight
- 0.91 kg (2 lb)
- Warranty
- 1 year factory warranty against defects and workmanship
- Other Technical Attributes
- Complete six-piece kit containing condenser, points and rotor with attaching hardware. Designed to resist RFI interference with onboard electronics.
What’s in the Box
- 1 × Complete Tune-Up Kit (391-5090Q1), which includes:
- 1 × Points (8M6001250)
- 1 × Condenser
- 1 × Rotor (8M6001224)
- 1 × Set of Attaching Hardware
Installation Notes
- Disconnect the negative terminal from your boat's battery for safety.
- Carefully remove the distributor cap, noting the orientation of the spark plug wires.
- Observe the exact position of the rotor, then pull it straight off the shaft.
- Remove the old ignition points and condenser from the distributor plate.
- Install the new points and condenser, ensuring all connections are secure.
- Set the point gap using a feeler gauge according to your engine's service manual specifications.
- Install the new rotor, aligning it in the same position as the original.
- Reinstall the distributor cap and secure its clips or screws.
- Reconnect the battery terminal and start the engine to test for smooth operation.
Troubleshooting & FAQ
How do I know if this kit fits my specific engine model?
This kit is designed for MerCruiser V8 engines using a Mallory conventional (points-based) ignition system. The most reliable way to confirm fitment is to verify your engine has this system and cross-reference your existing part numbers with those listed in our Part Number Matrix.
What are the signs of a failing ignition system?
Common symptoms of worn ignition components include engine misfires (especially under load), rough idling, difficulty starting, poor acceleration, backfiring, and reduced fuel economy.
What is the recommended replacement interval for these components?
For optimal performance and to prevent unexpected failures, it is generally recommended to inspect and replace tune-up components like points and condensers annually or according to the maintenance schedule in your engine's service manual.
What is the function of the condenser in this kit?
The condenser absorbs the surge of voltage when the ignition points open, which prevents arcing across the points. This action extends their life and helps the ignition coil produce a strong, consistent spark for complete combustion.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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