Here is an outboard maintenance checklist in your reference by using ePropulsion Navy Evo for instance: A spark plug which is fouled, worn, or has an poor hole is an additional dilemma that may lead to rough idling. https://mattiexobf852330.blogzag.com/74484661/how-much-you-need-to-expect-you-ll-pay-for-a-good-offshore-outboard-motors