PRODUCT DETAILS
Mercury Mariner Outboard 40 HP 50 HP 55 HP 60 HP 2-Stroke Thermostat 110°C
Maintain the correct engine operating temperature with this premium-quality aftermarket thermostat for Mercury and Mariner 2-stroke outboards. Manufactured to OEM specifications, this thermostat is a direct replacement for the original Mercury component and helps ensure efficient engine cooling and reliable performance.
Fits Mercury & Mariner Outboards
2-Stroke Models
40 HP (3 Cylinder)
- Serial Number 0P325500 & Up
- Serial Number 0T980000 – 1B208418
- Serial Number 0T980000 – 1B209735
40 Jet
- Serial Number 0P325500 & Up
- Serial Number 0T980000 & Up
50 HP (3 Cylinder)
- Serial Number 0P325500 & Up
- Serial Number 0T980000 & Up
- Serial Number 1B000001 & Up
55 HP (3 Cylinder)
- Serial Number 0P325500 & Up
- Serial Number 0T980000 & Up
60 HP (3 Cylinder)
- Serial Number 0P325500 & Up
- Serial Number 0T980000 & Up
Thermostat Specification
- Opening Temperature: 110°C
Replaces Mercury / Mariner Part Number
- 850055001
OEM part numbers are used for reference only.
Features
- Premium marine-grade aftermarket thermostat
- Direct replacement for Mercury / Mariner thermostat
- Opening temperature: 110°C
- Manufactured to OEM specifications
- Maintains correct engine operating temperature
- Helps prevent overheating and poor engine performance
- Fully compatible and interchangeable with the original component
- Suitable for freshwater and saltwater use
Why Replace Your Thermostat?
A faulty thermostat may cause:
- Engine overheating
- Engine running too cold
- Poor fuel economy
- Increased engine wear
- Reduced performance
Replacing the thermostat at the recommended service interval helps maintain efficient cooling and prolong engine life.
Why Buy From SSI Marine?
- Premium marine-grade aftermarket parts
- Workshop-tested by SSI Marine
- UK stock ready for immediate dispatch
- Same working day dispatch before 1 PM (Monday–Friday)
- Royal Mail Tracked 24 delivery
- Technical support available
- Collection available from our Leigh, Manchester workshop
Buyer Responsibility
Please check your engine model and serial number before ordering.
Although thermostats may appear identical, Mercury used different thermostats across various engine ranges.
If you are unsure, send us your engine serial number and we will be happy to confirm compatibility.
SHIPPING & DELIVERY
Delivery & Returns Policy
Delivery
Standard Delivery
- £6: Royal Mail Tracked 24 Service
- £3.99: Large Letter - Royal Mail 1st Class Post (Untracked)
We offer free delivery on all orders over £150 (excludes outboard engines).
Orders placed before 1:00 PM (Monday-Friday) are usually dispatched the same working day.
Most parcels are delivered within 24 hours, but please allow extra time for courier delays that may occur outside our control.
For outboard engines, please contact us for a delivery quote.
Important: Please ensure your shipping address is correct before completing checkout. SSI Marine is not responsible for parcels sent to an incorrect address provided by the buyer.
Tracking Your Order
Once your order has been dispatched, you will receive a tracking number via email (after 5 PM on the day of dispatch).
Tracking is available only for parcels sent via Royal Mail Tracked 24.
Large Letter orders are sent via Royal Mail 1st Class Post (untracked).
Returns
We accept returns of unused and undamaged items within 30 days of purchase.
Returned items must be in sellable condition and include the original packaging.
Please do not tape, label, or write directly on the product's original box.
Important: Do not return items in their original product boxes only, they must be placed inside a protective outer box or bag. Parcels returned like the example below will be subject to a 20% restocking fee.
Return shipping costs are the customer's responsibility.
Please include your order details and reason for return inside the parcel.
Refunds
Refunds are issued for the item purchase price only (shipping costs are non-refundable).
All refunds will be made using the same payment method as your original order.
Items returned in poor condition or without proper packaging may incur a 20% restocking fee.
YOU MIGHT ALSO LIKE
OFFICIAL PARTNERS OF
