Sierra 18-7202 Carburetor Float, Replaces Mercury Marine 3302-9031, for MerCruiser M2/Mercarb Carburetors

The Sierra 18-7202 is a brass carburetor float built to restore proper fuel level control in MerCruiser M2/Mercarb 2-barrel carburetors. The float rides inside the carburetor's fuel bowl and rises or falls with fuel level to open and close the needle valve, regulating how much fuel enters the bowl. A float that has absorbed fuel, cracked, or lost buoyancy causes flooding, hard starting, rough idle, or fuel leaking from the carburetor, and replacing it with a properly sized, alcohol-resistant unit restores accurate fuel metering.

This float is manufactured from brass and finished machined, and it is specifically formulated to resist the ethanol blends common in today's pump fuel, which is a frequent cause of premature float failure in older carburetors. It is designed for use in M2/Mercarb carburetors installed across a range of MerCruiser Mercruiser Carb# applications, including units built within the 6229718-C856558 serial number range and units built C856559 and above, paired with carb kits 18-7097 and 18-7098-1 depending on the specific carburetor. Always match the float to your carburetor's Mercruiser Carb# and serial number range before ordering.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7202
• Product Type: Carburetor Float
• Material: Brass
• Finish: Machined
• Fuel Resistance: Alcohol resistant
• Compatible Carburetor Type: MerCarb 2-Barrel (M2/Mercarb)
• Weight: 0.02 pounds
• UPC: 030999322142
• OEM Cross Reference: Mercury Marine 1397-5837, 3302-9031

Fitment

• MerCruiser M2/Mercarb carburetors, Mercruiser Carb# 1389-8490A2, serial number range 6229718-C856558, used with Carb Kit 18-7097
• MerCruiser M2/Mercarb carburetors, Mercruiser Carb# 1389-9350A2, serial number range 6229718-C856558, used with Carb Kit 18-7097
• MerCruiser M2/Mercarb carburetors, Mercruiser Carb# 1389-9562A1, serial number range 6229718-C856558, used with Carb Kit 18-7098-1
• MerCruiser M2/Mercarb carburetors, Mercruiser Carb# 1389-815396A2, serial number range C856559 and above, used with Carb Kit 18-7098-1
• MerCruiser M2/Mercarb carburetors, Mercruiser Carb# 1389-815397A2, serial number range C856559 and above, used with Carb Kit 18-7098-1

Replaces (OEM)

• Mercury Marine 1397-5837
• Mercury Marine 3302-9031

Frequently Asked Questions

What carburetor does the Sierra 18-7202 float fit? The Sierra 18-7202 is designed for MerCruiser M2/Mercarb 2-barrel carburetors, specifically the applications covering Mercruiser Carb# 1389-8490A2, 1389-9350A2, 1389-9562A1, 1389-815396A2, and 1389-815397A2.

Is the 18-7202 float alcohol resistant? Yes, the Sierra 18-7202 carburetor float is formulated to be alcohol resistant, which helps it hold up against the ethanol content found in today's pump gasoline.

What OEM part numbers does the 18-7202 replace? The 18-7202 corresponds to Mercury Marine float part numbers 1397-5837 and 3302-9031, so either of those OEM numbers points to this same float.

What is the 18-7202 float made of? It is made of brass with a machined finish, which is a common construction for carburetor floats that need to resist fuel absorption and hold consistent buoyancy over time.

How much does the Sierra 18-7202 float weigh? The Sierra 18-7202 carburetor float weighs 0.02 pounds.

How do I know if my carburetor float needs replacing? Signs that a carburetor float, such as the 18-7202, needs replacement include flooding at the carburetor, fuel leaking from the bowl, hard starting, and a rough or inconsistent idle caused by improper fuel level control.

Does the 18-7202 fit every MerCruiser carburetor? No, the 18-7202 is matched to specific MerCruiser M2/Mercarb applications identified by Mercruiser Carb# and engine serial number range, so it should be matched against your carburetor's carb number before ordering rather than assumed to fit universally.

What serial number ranges does the 18-7202 cover? The Sierra 18-7202 float covers M2/Mercarb applications built in the 6229718-C856558 serial number range as well as units built C856559 and above, depending on the specific Mercruiser Carb# involved.

What carb kits pair with the 18-7202 float? Depending on the specific M2/Mercarb application, the 18-7202 float is used alongside carb kit 18-7097 or carb kit 18-7098-1.

Is the Sierra 18-7202 a genuine Mercury part or an aftermarket replacement? The 18-7202 is a Sierra-manufactured replacement float engineered to match the fit and function of Mercury Marine floats 1397-5837 and 3302-9031, rather than a part sold under the Mercury Marine brand itself.