SKU: 97328621493

6G9-85540 CDI Unit for Yamaha Mercury | JLM Marine

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Description

6G9-85540 CDI Unit for Yamaha Mercury | JLM MarineCDI Unit for Yamaha Mercury 4 Stroke Outboard 8HP 9. 9HP Direct Replacement for 6G9 85540 This aftermarket CDI (Capacitor Discharge Ignition) unit is engineered to fit Yamaha 9. 9 HP 2 cylinder engines (19852005) and Mercury Mariner 8 HP and 9. 9 HP 2 cylinder 4 stroke outboards (19952000). It delivers reliable ignition performance across a wide range of model years for both brands. This unit directly replaces Yamaha 6G9 85540 20 00, 6G9 85540 21 00,

CDI Unit for Yamaha Mercury 4-Stroke Outboard 8HP 9.9HP | Direct Replacement for 6G9-85540

This aftermarket CDI (Capacitor Discharge Ignition) unit is engineered to fit Yamaha 9.9 HP 2-cylinder engines (1985–2005) and Mercury/Mariner 8 HP and 9.9 HP 2-cylinder 4-stroke outboards (1995–2000). It delivers reliable ignition performance across a wide range of model years for both brands.

This unit directly replaces Yamaha 6G9-85540-20-00, 6G9-85540-21-00, 6G9-85540-22-00, 6G9-85540-29-00, and Mercury 825667, 825667T, ensuring seamless compatibility with your existing electrical system.

  • Fits both Yamaha and Mercury 2-cylinder 4-stroke outboards
  • Direct plug-and-play replacement for OEM ignition packs
  • Covers multiple model years from mid-1980s to mid-2000s

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Brand Part Number
Yamaha 6G9-85540
Yamaha 6G9-85540-22
Yamaha 6G9-85540-20-00
Yamaha 6G9-85540-21-00
Yamaha 6G9-85540-22-00
Yamaha 6G9-85540-29-00
Mercury 825667
Mercury 825667T

Compatible Engine Models

Confirm your engine model/year in the table below. For Yamaha owners, here's a guide to help you identify your engine's serial/model: Yamaha Serial Number Guide. You can also review exploded diagrams to verify part numbers: Yamaha Parts Diagrams & Catalog.

For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Brand Rated HP Stroke Years
Yamaha 9.9 HP 2-Cylinder 1985–2005
Mercury/Mariner 8 HP 2-Cylinder 4-Stroke 1995–2000
Mercury 9.9 HP 2-Cylinder 1995–1998

Technical Specifications

Specification Value
Product Type CDI Unit (Capacitor Discharge Ignition)
Compatibility Yamaha 9.9 HP 2-Cylinder (1985–2005), Mercury/Mariner 8 HP & 9.9 HP 2-Cylinder 4-Stroke (1995–2000)
OEM Replacement Yamaha 6G9-85540 series, Mercury 825667/825667T

Package Contents

  • 1 × CDI Unit for Yamaha Mercury 4-Stroke Outboard 8HP 9.9HP

Installation Guide

  1. Disconnect the battery: Remove the negative cable to ensure all electrical power is off before beginning work.
  2. Locate the existing CDI unit: It is typically mounted near the engine block or under the cowling. Consult your service manual if unsure.
  3. Disconnect wiring harness: Carefully unplug all connectors from the old CDI unit. Note the wire colors and positions for reference.
  4. Remove mounting hardware: Unbolt or unclip the old CDI unit from its bracket.
  5. Install the new CDI unit: Position the replacement unit in the same location and secure it with the original mounting hardware.
  6. Reconnect wiring harness: Attach all connectors to the new CDI unit, ensuring each plug is fully seated and secure.
  7. Reconnect the battery: Reattach the negative cable and ensure all connections are tight.
  8. Test the ignition system: Turn the key to the ON position and attempt to start the engine. Verify smooth ignition and consistent running.
  9. Check for error codes: If your engine has a diagnostic system, confirm no fault codes are present.
  10. Perform a sea trial: Run the engine at various RPMs to ensure stable performance and proper timing under load.

Troubleshooting & FAQ

How do I confirm this CDI unit fits my engine?
Check the compatibility table above for your engine's brand, HP, and year range. Cross-reference your original part number (6G9-85540 series for Yamaha or 825667/825667T for Mercury) to ensure a match.

What are the signs that my CDI unit is failing?
Common symptoms include hard starting, intermittent misfires, loss of power at high RPM, or complete failure to spark. If you've ruled out spark plugs and coils, the CDI unit is often the next component to check.

How often should I replace the CDI unit?
CDI units typically last many years under normal use. Replace only if you experience ignition problems or if diagnostics point to CDI failure. There is no fixed maintenance interval.

Will this aftermarket CDI perform the same as the OEM unit?
Yes. This unit is built to OEM specifications and delivers equivalent ignition performance. It is tested to ensure reliable spark timing and durability across the full RPM range.

Can I install this CDI unit myself?
If you have basic mechanical and electrical skills, installation is straightforward—disconnect the old unit, swap in the new one, and reconnect the wiring. However, professional installation is recommended to avoid incorrect wiring or damage.

OEM vs. Aftermarket?
This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?
We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?
This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

  • Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
  • This product is an aftermarket replacement part and is not an OEM component.
  • Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

  • Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
  • Fast Global Shipping: Free delivery worldwide in 5–15 days.
  • Direct from Manufacturer: Competitive pricing without compromising quality.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 97328621493

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4.1 ★★★★★
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Thomas P. Ulrick
Grantham, US
★★★★★ 5
The Best Cable Management Solution for IT Work — Reusable, Reliable, and Professional
Size: 150Pk - 8" x 1/2", Style: Cord Wrap Cable Ties, Color: Black and Gray
TL;DR: I’ve been using these VELCRO Brand cable ties for years as an IT field tech. They hold tight, are endlessly reusable, and keep cables tidy. Great for both home and professional setups. Full Review: As an IT field technician, I’ve tried countless ways to keep cables organized, and these VELCRO Brand cable ties are simply the best. They’re reusable, strong, and easy to reposition — ideal for network racks, AV installs, or just cleaning up cords around the house. Functionality: Top-notch. The hook-and-loop material is aggressive enough to hold firmly, but not so sticky that it clings to everything else in your tool bag. They wrap cleanly, stay put, and release easily when you need to re-route cables. They’re reliable enough for professional jobs and flexible enough for home use. Storage Capacity: Each strap holds more than you’d expect — I rarely need to link two together. They handle thick cable bundles or power cords just fine on their own. And when I do need more length, it’s easy to join a second strap for a larger wrap. The two-color mix (black and gray) is great for keeping different cable types separated — for instance, network vs. power. The thin profile also helps keep bundles neat and professional-looking. These have earned me plenty of compliments from higher-ups for clean cable runs and well-organized setups. Once you switch to these, you’ll never want to deal with cutting zip ties again.
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Reviewed in the United States on October 12, 2025
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Ranger Mike
Lowell, US
★★★★★ 5
VELCRO Ties Are the Standard to Rely On
Size: 150Pk - 8" x 1/2", Style: Cord Wrap Cable Ties, Color: Black and Gray
I am a big fan of VELCRO brand products because of their quality and utility. I have used their rolls of Velcro hook and loop tape as well as their little patches, and I became a brand loyalist. Yes, there are many other manufacturers, but these are certainly as good as it gets. This product is your very basic, very thin, and very copious supply (for my neighbors in Rio Linda - that means plenty of them). You get two big spools of these little eight (8) inch ties that are adhesive throughout their length - that means you can tie the smallest cables to anything almost up to their full length. If you need a longer wrap - use more than one and just extend the length by piggy backing them. The real advantage of this bulk package is that you are not tempted to save some for later - you have enough to use as many as you like and can happily go tie crazy on all your cords! It's VELCRO party time. We live in an electronic age, and I have a lot of more pricey hook-and-loop specialty ties, and I try to keep a few back as spares. Forget that - with these little ties, I can actually use them and do what I need to get those tangled cords in shape. O.K. maybe I am a geek, but I cook my chicken - dead already, and I believe in independent segregated wiring and not tripping over things or spending time untangling messes when I need to move gear. These big rolls will make your life easier - I use them to attach notes to little jars or vials - to tie two gloves together when I am not wearing them - and other uses even cutting them into smaller pieces. That's one of the advantages of these bulk spools - lots of supply. Yes, the individual ties are dinky thin little things, but they hold very well (why you buy genuine VELCRO) and you don't feel stupid using them up on anything you feel like. They are expendable, and that adds to their ultimate utility. Darned useful product. Buy it - use it; enjoy.
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Reviewed in the United States on February 17, 2024
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Amiga95
Cuba, US
★★★★★ 5
Computers, electronics cabling? You NEED these!
Size: 100Pk - 6” x ½”, Style: Cord Wrap Cable Ties, Color: Black
If you do any cabling, be it TV or computer or anything else, these ARE worth there weight in gold. Seriously! They'll keep your cable runs, extension cords, etc in a nice neat easy to work with bundle that you can have out of the way. Adhesion is very good also which is also important. Just the right size for most applications and if you need something large they make them to fit your needs. Cable management has always been a pet peeve of mine and makes a difference that not only shows but makes future work and maintenance much easier. Whenever I see a rat's nest cluster of wires I always know it means shoddy workmanship!
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Reviewed in the United States on May 9, 2026
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Verified Purchase
Arvid
West Palm Beach, US
★★★★★ 4
Very Effective, but Not the Instructions
Size: 150Pk - 8" x 1/2", Style: Cord Wrap Cable Ties, Color: Black and Gray
These work very well, but when you remove them from the box, you see two donuts, one grey, one black, of 75 tightly wrapped cable ties each. So far, so good. First deficiency: The "how to use" pictures---three of them---are tiny light line drawings in 7/16" x 7/16" boxes. If you don't have a 400-power microscope, maybe a magnifying glass will do. Maybe Velcro---a "name" brand that should know better---thinks that the use of these devices is obvious. Well, "obvious" is obvious only when it's obvious, and that can vary from person to person. They should assume nothing. Second deficiency: Before trying (and, one hopes, succeeding) at using these ties, one must determine exactly now to remove the first tie from the outside of either donut. Obvious? No, not really, because, as it turned out, it requires some effort to remove the first one---the placement and circumstances of which do not at all (not on my set of these, anyway) suggest in any concrete way which one should be taken first. No one wants to tear up a couple of ties just to figure out how not to tear up ties by removing them incorrectly or out of order. The punishment here is four stars that could have been five.
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Reviewed in the United States on May 13, 2026
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Verified Purchase
Farmboy
Battle Creek, US
★★★★★ 5
Must Have for Cable Management.
Size: 100Pk - 6” x ½”, Style: Cord Wrap Cable Ties, Color: Black
Best Velcro out the. Great for cable management. Super easy to use. Cannot be beat for the price. Incredibly useful.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on April 29, 2026

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