Automotive Authority Mercury Optimax Ignition Coil 339-879984T00 300-8M0077471 300-879984T01
Key features
- •This ignition coil meets or exceeds OEM specifications
- •Replaces Mercury part # 3008M0077471, 300-879984T01, 300-8M0077471, 339-879984A1, 339-879984T00, 879984T01, 8M00774714, 184-0003
- •Direct replacement
- •Check Compatibility List Below (Compare your part numbers as well)
BrandAutomotive Authority
CategoryCoils
Automotive Authority Mercury Optimax Ignition Coil 339-879984T00 300-8M0077471 300-879984T01
List Price: $43.63$39.27DEALYou Save: $4.36 (10%)
Free shippingFree Returns – 30 daysFree Order CancellationSecure Payment2–3 Days DeliveryGet It June 23, 2026In Stock (2)No marketing spamNo account requiredFulfilment by FedEx / Amazon / UPS / ShipwirePayPal / Card Buyer Protection
Customer Reviews
Reviews sourced from verified Amazon purchasers3.7
out of 5
Based on 6 reviews
5★
67%
4★
0%
3★
17%
2★
0%
1★
17%
a bad coil can fry your ECM
Florida Amazon Customer•June 5, 2018
If I could rank ZERO stars, I would, except that they did at least require a signature for delivery...which is about the only redeeming factor.
First off, I don't even know if I received the correct product because the units are individually boxed with no part numbers and exactly no identifying data. Yes, they look identical to the OEM product, but that really doesn't mean anything at all.
Secondly, these coils are sold as an aftermarket unit that states in the description: "This ignition coil meets or exceeds OEM specifications". After I received the shipment, I grabbed a few of the coils and tested the resistance across the pins with a multi-meter. I have the specified values on a chart from the actual Mercury Service Manual. Right off the bat, they fell outside of the range and some of the tests showed full continuity where there was supposed to be 12K to 20K ohms.
I'm guessing that the other positive reviews received on this item did not actually check with a multi-meter and/or didn't actually confirm the performance criteria. According to a service bulletin from Mercury, a bad coil can fry your ECM.
I called Mercury Marine direct (service support in Wisconsin). The technician I spoke with confirmed that the resistance values have not changed with the updated part numbers, and the chart I have is still valid. Therefore I'm led to believe that this aftermarket coil is either the wrong ones, poorly manufactured, or simply does not come close to meeting spec. They were more than half as much as the OEM units, but I'll be returning these and ordering the right ones. Sometimes you do indeed get what you pay for.
First off, I don't even know if I received the correct product because the units are individually boxed with no part numbers and exactly no identifying data. Yes, they look identical to the OEM product, but that really doesn't mean anything at all.
Secondly, these coils are sold as an aftermarket unit that states in the description: "This ignition coil meets or exceeds OEM specifications". After I received the shipment, I grabbed a few of the coils and tested the resistance across the pins with a multi-meter. I have the specified values on a chart from the actual Mercury Service Manual. Right off the bat, they fell outside of the range and some of the tests showed full continuity where there was supposed to be 12K to 20K ohms.
I'm guessing that the other positive reviews received on this item did not actually check with a multi-meter and/or didn't actually confirm the performance criteria. According to a service bulletin from Mercury, a bad coil can fry your ECM.
I called Mercury Marine direct (service support in Wisconsin). The technician I spoke with confirmed that the resistance values have not changed with the updated part numbers, and the chart I have is still valid. Therefore I'm led to believe that this aftermarket coil is either the wrong ones, poorly manufactured, or simply does not come close to meeting spec. They were more than half as much as the OEM units, but I'll be returning these and ordering the right ones. Sometimes you do indeed get what you pay for.
Exact fit.
baitmaster•May 9, 2018
Exact replacement for my Merc.
Five Stars
Amazon Customer•April 14, 2018
works as good as the original and much cheaper.
Easy fix and a hundred bucks less.
Manny•October 31, 2017
I have been running this almost daily since I bought. It is running strong and I haven't had a problem since. OVER $100 CHEAPER THAN THE DEALERS.
It was easy to diagnose as I could tell which cylinder was dead by pulling plug wires one at a time. I then swapped the coil with one of the othe two and the dead cylinder was now where I had moved the coil to.
Amazon got it to me at least 2 days faster than the dealer(s) could at $163. They all had the same price and it was out of stock.
It was easy to diagnose as I could tell which cylinder was dead by pulling plug wires one at a time. I then swapped the coil with one of the othe two and the dead cylinder was now where I had moved the coil to.
Amazon got it to me at least 2 days faster than the dealer(s) could at $163. They all had the same price and it was out of stock.
Great deal.
Kindle Customer•October 2, 2017
Worked for 2006 mercury 40 hp 4 stroke bigfoot. Appearance was the same as original, it seems well built. I am ordering a spare at this price. Great deal.
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