FourStroke 75 · 90 · 115 · 150 · V6 3.4L · V8 4.6L · Verado L6 · Verado V10
Mercury engines are particular: a supercharged Verado and a 115 FourStroke do not take the same oil, the same filter or the same amount. Here is what each family needs, how the job is done properly, and how we do it where the boat sits.
Mercury's schedule is the same across the range: engine oil and filter every 100 hours or once a year, whichever comes first, with the level checked before every trip. What changes is the oil itself. Most of the FourStroke range runs Mercury's 25W-40 synthetic blend; some engines are specified for 10W-30; the supercharged Verado L6 has its own history, with 25W-50 on older serial numbers and 25W-40 on later ones. The label under the cowl and the serial number settle it, not the shelf at the store.
Every oil Mercury approves carries the NMMA FC-W certification, the marine four-stroke standard. Automotive oil does not, and the difference is corrosion protection and the ability to hold water in suspension, which is exactly what a saltwater engine needs.
The Verado adds one more thing: it is supercharged and runs hot. Clean oil at the right level is what keeps the supercharger bearings and the top end alive, which is why a Verado that misses a year shows it sooner than a 90 FourStroke does.
Mercury's procedure, in the order we follow at the boat.
Mercury sets the oil, the capacity, the filter and the plugs by serial number range, and the same horsepower has been built on more than one engine. Nothing here is quoted from a chart; it is pulled for your serial before we arrive.
This is why we ask for the serial number before the visit: the kit is right the first time, with no second trip.
Mercury's 25W-40 synthetic blend, one price, no choice to make. On a Mercury the answer is simple: Mercury's 25W-40 synthetic blend, the grade Mercury prints on the label, at one price per engine. Mercury does not make a 25W-40 full synthetic, so there is no upsell and no cheaper grade to pick between. On the Verado the label and the serial decide the grade Mercury allows, and we stay inside it.
A Mercury serviced on time keeps clean oil between changes. Anything on this list is a reason to have it looked at.
The Mercury oil change is owner-doable, and the Verado is where it bites. Wrong viscosity for the serial, the level read with the engine tilted, overfilled because the bottle said so, the drain seal reused, the filter cranked on with a wrench. On a Verado add the supercharger belt and the two different fuel filter systems depending on when it was built. And the oil is a quarter of what Mercury schedules at 100 hours: gear oil, fuel filter, plugs check, thermostat, anodes, belt, and the water pump at 300 hours. Those are the parts that fail on a saltwater boat when they are skipped.
Can I choose standard oil instead of full synthetic on a Mercury?
On a Mercury there is one oil: Mercury's 25W-40 synthetic blend, the grade on the label, at one price per engine. The standard-or-full-synthetic choice applies to Yamaha engines, where both are priced and you pick on the booking page.
How often does a Mercury outboard need an oil change?
Every 100 hours or once a year, whichever comes first, oil and filter together. Check the level before each trip. In this climate the year usually arrives before the hours.
What oil does a Mercury outboard take?
A Mercury or Quicksilver NMMA FC-W marine four-stroke oil in the viscosity on your engine's label and in the manual. Mercury's 25W-40 synthetic blend is its standard four-stroke oil; the Verado has its own history. Not automotive oil.
What oil does a Verado take?
The synthetic blend Mercury lists for your serial. Mercury has recommended both its 25W-50 and its 25W-40 synthetic blends for the Verado over the years, so the engine's label and manual decide, and the V10 follows its own label.
Why do you ask for the serial number before an oil change?
Because Mercury sets the oil, the capacity, the filter and the plugs by serial range, not by horsepower, and the same horsepower has been built on more than one engine. The serial pulls the exact kit, and the dipstick, not a chart, sets the level.
Does the oil change include the filter and the seal?
Yes. Mercury oil, the genuine filter and a new drain seal every time, with the old oil read before it leaves. Oil without the filter is half a job.
What oil filter does my Mercury use?
The genuine Mercury filter for your serial number. The FourStroke, V6 and V8, Verado L6 and V10 families each use their own, and Mercury changes them by serial range inside the same horsepower, so we look it up rather than quote a number that may be one revision old.
Do you do just the oil change?
The oil change is part of the Premium Full Service: oil and filter, gear oil and seals, fuel filter, plugs, thermostat, water pump kit, belt and anodes where the schedule calls for them, parts included, one price per engine. Oil alone leaves the parts that actually fail.
Is the Verado different to service?
Yes. It is supercharged, runs hot, takes iridium plugs, has a drive belt on the 300-hour list, and changed fuel filter systems partway through production. The kit and the oil are matched to the serial, not the horsepower.
We come to the boat with the Mercury oil your engine is labeled for, the genuine filter and drain seal for your serial number, and the container the old oil leaves in. It is done as part of the complete 100-hour service, every item on Mercury's list for your family, with the level set engine-down and checked again after the run. You get the hours, the date and what we found in writing, and the next service goes on the calendar before we leave.
What it costs: this job is part of the Premium Full Service — the complete outboard service, parts included, one price per engine, in writing before we come. The serial number sets the price, so text us a photo of the plate. Nothing is added at the dock; sales tax is its own line at your county's rate.
Something wrong, not just due? That is a $250 diagnostic visit at the boat in regular hours ($295 after hours, Sundays and holidays): we find the actual cause and quote parts and labor before any work starts.
Dock, lift, marina, driveway or storage lot — we come to the boat across Southwest Florida:
Text us the engine model, the year and where the boat sits. You get one price per engine, parts included, in writing, and a day on the calendar. We come to the boat.
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