Recmar Mercury OptiMax Thermostat 143F 833072003 18-3536
REC833072003
- Dispatched in 2-3 days
- 30 Day Return Policy
- In stock, ready to ship
- Backordered, shipping soon
Recmar Mercury OptiMax Thermostat
143°F / 62°C | Replaces 833072003
Aftermarket thermostat for selected Mercury OptiMax direct-fuel-injected two-stroke outboards. Mercury used this thermostat across more than one OptiMax family, with serial boundaries that must be respected.
Key Features
- 143°F (approximately 62°C) thermostat specification
- For selected Mercury OptiMax DFI two-strokes
- Serial-range fitment stated below
- Aftermarket Recmar part; not genuine Mercury
- One thermostat supplied
Technical Specs
| Part type | Outboard cooling thermostat |
| Opening temperature | 143°F / approximately 62°C |
| Engine system | Two-stroke DFI / OptiMax |
| Quantity | 1 thermostat |
| 4Boats SKU | REC833072003 |
Compatibility / Fitment Guide
| Engine / system | Application | Fitment condition |
|---|---|---|
| Mercury OptiMax 75–115 hp | Specified DFI outboards | Serial 1B227000 onward where parts diagram lists 833072003 |
| Mercury OptiMax 135 / 150 / 175 hp | 2.5L DFI family | Common serial range 0T801000 through 1B226999; verify exact model |
| Johnson / Evinrude cross-reference applications | Only engines whose OEM/service catalogue crosses to the 437090 thermostat family | Confirm temperature, dimensions and gasket separately |
Not for every OptiMax or Mercury two-stroke. Earlier/later serial ranges, 3.0L 200–300 hp DFI families and engines updated by service bulletin can require different thermostat assemblies or covers. Not a MerCruiser inboard thermostat.
Part Number Cross Reference
| Mercury / Mariner | 833072002; 833072003; 833072004 |
| Sierra | 18-3536 |
| OMC cross-reference family | 0437090; 5000355; 5005440 — verify application |
| Recmar / 4Boats SKU | REC833072003 |
Cross-reference numbers identify compatible service applications; they do not make this aftermarket Recmar part a genuine OEM component.
Frequently Asked Questions
Will it fit every Mercury OptiMax?
No. Use the horsepower, displacement and serial boundaries in the fitment guide.
How many thermostats are required?
This listing supplies one; check the engine diagram for the quantity fitted.
Is it 143°F?
Yes, approximately 62°C.
Is a gasket included?
Only if clearly shown. Match and order the required seal separately when necessary.
Before ordering: match 833072003 in the serial-specific Mercury diagram and confirm the number of thermostats required.
For the products under £150 the shipping is £6.99.
Free delivery for most items over £150.
