Sierra 18-99421 MerCruiser Voltage Regulator

Sierra 18-99421 MerCruiser Voltage Regulator Replaces CDI 194-9502

Sierra 18-99421 Voltage Regulator Application Information

• Fits: 470 w/2 BBL Carb from 1976-1984
• Fits: 485 & 488 w/ 2 BBL Carb from 1980-1984
• Fits: 170 & 190 from 1985-1986
• Fits: 165 & 180 from 1987
• Fits: 3.7L from 1988-1989

Interchangeable With:

• CDI
• 194-9502
• Mercury
• 77305A2
• 86255A2
• 86255A3
• 99502A12
• 99502A13
• 99502A7
• 99502A8
• 99502A9

Click here for Sierra 18-99421 Voltage Regulator Installation Instructions

Frequently Asked Questions

What is the Sierra 18-99421 MerCruiser Voltage Regulator used for?

The Sierra 18-99421 MerCruiser Voltage Regulator is a replacement voltage regulator designed for use with MerCruiser electrical systems. It is listed for specific MerCruiser engine applications ranging from 1976 through 1989, depending on the engine model and configuration.

What MerCruiser engines does the Sierra 18-99421 Voltage Regulator fit?

The Sierra 18-99421 fits 470 engines with 2 BBL carburetors from 1976-1984, 485 and 488 engines with 2 BBL carburetors from 1980-1984, 170 and 190 engines from 1985-1986, 165 and 180 engines from 1987, and 3.7L engines from 1988-1989.

Does the Sierra 18-99421 replace CDI 194-9502?

Yes. The Sierra 18-99421 Voltage Regulator is listed as interchangeable with CDI 194-9502. This replacement reference can help when comparing the existing voltage regulator or part number before ordering.

What Mercury part numbers are interchangeable with the Sierra 18-99421?

The Sierra 18-99421 is interchangeable with Mercury 77305A2, 86255A2, 86255A3, 99502A12, 99502A13, 99502A7, 99502A8, and 99502A9. Compare your existing part number and verify the specific engine application before ordering.

Is the Sierra 18-99421 compatible with MerCruiser 3.7L engines?

Yes. The application information lists the Sierra 18-99421 for MerCruiser 3.7L engines from 1988-1989. Confirm your engine model and year against the listed application information before using this voltage regulator.

What should I verify before ordering the Sierra 18-99421 Voltage Regulator?

Verify your MerCruiser engine model, year, and configuration against the listed applications. For the 470, 485, and 488 applications, also confirm the 2 BBL carburetor configuration. Comparing the existing regulator's part number with the listed CDI and Mercury references can provide an additional fitment check.

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