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Thermo Sensor 804295T – Mercury Mariner 75-115 HP
- $55.77
- $55.77
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How to Match This Part
This aftermarket thermosensor replaces Mercury / Mariner 804295T. It is a threaded engine-temperature sensor used on supported Mercury and Mariner four-stroke outboards in the 75–115 HP range.
Match this part in this order:
1. Number on the sensor you remove — 804295T
2. Engine family — Mercury / Mariner 4-stroke carbureted or EFI at 75, 80, 90, 100, or 115 HP
3. Serial number on the engine ID plate / midsection mounting bracket against the serial blocks below, then compare the threaded metal tip, hex flats, and black molded connector with the product images
This listing is a brand-new sensor — not a remanufactured unit. Do not order by horsepower alone when a serial-number range is listed.
Compatible Engine Models
Confirm your engine model and serial number on the mounting bracket or cowling identification plate. Use the Mercury Serial Number Guide and Mercury Parts Diagrams to verify the thermosensor callout on your Sensors diagram.
| Brand | Engine Family | Rated HP / Models | Serial / Notes |
|---|---|---|---|
| Mercury / Mariner | 4-Stroke carbureted | 75, 90 (incl. Bodensee 75) | 0G960500 THRU 1B226999 |
| Mercury / Mariner | 4-Stroke EFI | 75 EFI, 90 EFI | 1B172291 THRU 1B366822 |
| Mercury / Mariner | 4-Stroke EFI | 80 EFI, 100 EFI | 1B227000 THRU 1B366822 |
| Mercury / Mariner | 4-Stroke EFI | 115 EFI | 0T178500 THRU 1B366822 |
Always match the number stamped on the sensor you remove. Engines outside these where-used groups use different temperature-sensor part numbers.
Technical Specifications
| Specification | Value |
|---|---|
| Part type | Thermo / engine temperature sensor (thermosensor) |
| Primary OEM number replaced | 804295T |
| Application | Mercury / Mariner 4-stroke outboard temperature sensing |
| Mounting form | Threaded metal sensing tip with hex wrench flats |
| Connector | Integral black molded electrical connector housing |
| Condition | Brand new (not remanufactured) |
| Horsepower coverage (verified where-used) | 75, 80, 90, 100, 115 HP 4-stroke (serial-limited) |
Installation Guide
- 1Turn the ignition off and disconnect the negative battery cable before opening the cowling or unplugging sensors.
- 2Locate the thermosensor on the powerhead / sensors group per your engine’s parts diagram. Note connector orientation before unplugging.
- 3Unplug the harness, then unscrew the old sensor from its boss using the hex flats. Compare the new unit side by side — threaded tip, hex body, and molded connector should match.
- 4Thread the new sensor in by hand to avoid cross-threading, then tighten to the torque values in your Mercury / Mariner service manual. Do not overtighten the metal body into the boss.
- 5Mate the connector until it latches, route the harness clear of moving parts and heat sources, and reconnect the battery.
- 6Start the engine and confirm there are no coolant or sealing leaks at the sensor boss and no temperature-related warning codes after a warm-up cycle.
Note: Professional installation is recommended. OEM diagrams list a separate thermosensor gasket on some engines — replace that gasket only when your diagram and service procedure call for it; it is not included with this sensor.
Troubleshooting & FAQ
Important Notes
- Verify the OEM number on your original sensor and your engine serial against the compatibility table before ordering.
- This sensor is sold alone; replace any separate thermosensor gasket only when your OEM diagram and service procedure require it.
- This is an aftermarket replacement and is not a genuine Mercury Marine / Mariner OEM component.
- Professional installation is recommended for powerhead temperature sensors on 4-stroke outboards.
Why Choose JLM MARINE?
- Precision Fit: Cross-referenced to Mercury 804295T for the listed 75–115 HP 4-stroke Mercury / Mariner applications.
- Quality Control: Each batch is inspected for dimensional consistency and workmanship.
- Direct from Manufacturer: Aftermarket marine thermosensors engineered for reliable engine-temperature feedback.
We can ship to virtually any address in the world with free shipping available for most regions.
For our typical US and Canadian customers , our shipping timeframes are as follows:
- Amazon FBA: orders will be delivered within 1-5 business days after placing the order (during certain special periods such as major promotions, Christmas, etc., the delivery time of Amazon FBA may be affected).
- US warehouse shipment: orders will be delivered within 5 days after placing the order.
- China warehouse shipment: orders will be delivered about 12 days after placing the order.
When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.
Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.
Founded in 2002, JLM Marine has established itself as a dedicated manufacturer of high-quality marine parts, based in China. Our commitment to excellence in manufacturing has earned us the trust of top marine brands globally.
As a direct supplier, we bypass intermediaries, which allows us to offer competitive prices without compromising on quality. This approach not only supports cost-efficiency but also ensures that our customers receive the best value directly from the source.
We are excited to expand our reach through retail channels, bringing our expertise and commitment to quality directly to boat owners and enthusiasts worldwide.
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