Spark Plug Type MerCruiser MCM 4.3 L V6

Question

What are the correct brand of spark plug for a MerCruiser 4.3 L V6 LX Alpha 1 engine? I could also use the spark plug gap spec. Thank you.

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Jeffrey Petree 4 months 2021-02-08T19:18:57+00:00 1 Answer 78 views 1

Answer ( 1 )

  1. The factory service manual recommends two brands of spark plugs. Which one you choose is up to you. You can use AC Delco or Champion.

    Here are links to the correct type of spark plugs:

    AC Delco spark plugs: https://amzn.to/39YySNa

    Champion spark plugs: https://amzn.to/2MKVk3v

    Here is a screenshot of spark plug specifications from the factory service manual.

    Applicable Models

    The spark plug specifications on this page are relevant to the following models 1983 thru 1993 GM six-cylinder engines.

    MODEL SERIAL NUMBER
    MCM 185R 229 CID 3.8L 6289593 – 6919655
    MCM 185 MR 262 CID 4.3L 6919656 – OA4835680
    MCM 185 Alpha 1 OA483581 – OB455459
    MCM 175 Alpha 1 OB455460 – OB773242
    MCM 4.3 Liter Alpha I OB773243 – OF000000
    Sea Ray 4.3L-2 Alpha I (See note) OB785483 – B921276
    MCM 205MR 6919687 – OA483776
    MCM 205 Alpha I OA483777 – OB775129
    MCM 4.3 Liter LX Alpha I OB775130 – OF000000
    Sea Ray (See note) 4.3L-4 Alpha I OB785981 – B922330


    Notations: Sea Rap to MerCruiser cross references include;
    4.3L-2 same as MCM 4.3L
    4.3L-4 same as MCM 4.3LX

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