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Mercury Mariner 40-150HP Thermoswitch 819502
| Quantity | Price |
| 1 | 72.95 |
Mercury Electrical and Cooling
Mercury Mariner 40-150HP Thermoswitch 819502
Mercury 819502 is a thermoswitch, also called a temperature switch or overheat switch, used on select older Mercury and Mariner outboard engines. It is part of the engine temperature monitoring system and is commonly tied into the overheat warning circuit.
This switch appears in electrical, ignition, and cylinder block diagrams on select 2-stroke and early 4-stroke applications, commonly in the 40-150HP range. Fitment varies by model, year, and serial number, so always verify by OEM diagram before ordering.
Compatible Applications
| Brand | Engine / System | Application | Fitment Note |
|---|---|---|---|
| Mercury / Mariner | Select older 2-stroke outboards | Temperature monitoring and overheat warning circuit | Commonly found in the 40-150HP range where 819502 is listed |
| Mercury / Mariner | Select early 4-stroke outboards | Thermoswitch / temperature switch | Verify by model and serial number |
| Mercury / Mariner | Select Jet and conversion kit applications | Electrical or cylinder block mounted switch | Used only where OEM number 819502 is shown in the diagram |
Important Fitment Note
Temperature switch fitment depends on the engine family, serial number, wiring harness, warning system, and cylinder block configuration. Always confirm compatibility using your engine serial number, model, and OEM parts diagram before ordering.
OEM & Cross Reference Numbers
| Mercury OEM Number | 819502 |
| Description | Thermoswitch / Temperature Switch / Overheat Switch |
| Known Supersessions | No supersession provided |
What This Part Is Used For
This thermoswitch helps monitor engine temperature and can trigger the overheat warning circuit when temperature rises beyond the intended range. On many older Mercury and Mariner outboards, it is connected to the warning horn or related protection circuit.
A faulty thermoswitch may cause no overheat warning, a warning horn that activates incorrectly, or temperature warning issues during operation. Replace the switch if testing confirms it is damaged, corroded, or not responding correctly.
Key Features and Benefits
- Mercury thermoswitch part number 819502
- Used for temperature monitoring and overheat warning functions
- Commonly found on select older Mercury and Mariner outboards
- Associated with select 40-150HP, Jet, and conversion kit applications
- Important electrical cooling-system component for engine protection
- Direct replacement where OEM number 819502 is specified
FAQ
What is Mercury 819502?
Mercury 819502 is a thermoswitch, also called a temperature switch or overheat switch, used on select Mercury and Mariner outboards.
What does this switch do?
It monitors engine temperature and is commonly tied into the warning horn or overheat warning circuit.
Does this fit every Mercury 40-150HP outboard?
No. It is used on select older models only. Always verify by model, serial number, and OEM parts diagram before ordering.
What are signs of a bad thermoswitch?
Possible symptoms include incorrect warning horn operation, no overheat warning, intermittent temperature alerts, or corrosion at the switch connection.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer, technician, boat builder, or industry professional? We offer dealer pricing for qualified marine businesses.
Shipping Policy
- Free shipping on orders over $100 continental U.S.
- Orders ship via UPS, USPS, and FedEx.
- Orders received before 5:30 PM EST ship the same business day.
- Typical delivery time is 1-5 business days.
30-Day Return Policy
- Returns accepted within 30 days of delivery.
- Parts must be new, unused, and in original packaging.
- Installed parts are not returnable.
- Return authorization is required before sending items back.
Need help with a return or order question?
Contact Us
Phone: 941-721-3000
Searchable Terms
Mercury thermoswitch, Mercury temperature switch, Mercury overheat switch, Mariner thermoswitch, Mariner temperature switch, Mercury warning horn switch, Mercury outboard temp switch, Mercury cooling warning switch, Mercury electrical switch
Searchable Part Numbers
819502