Is the 100-hour service the same as winterization?

No. They can overlap, which is why Ontario shops often combine them. Scheduled service follows the exact maintenance table; winterization adds the model-specific fuel, internal-protection, battery, drainage, and storage-position steps. The scope varies by engine.

My motor only ran 40 hours this year. Do I still need the service?

Possibly. Mercury says most FourStroke outboards require an oil change annually or every 100 hours, and some other items have different intervals. Follow the owner's manual and serial-specific schedule rather than hours alone.

What parts get replaced at a typical annual service?

There is no one replacement list. Engine oil and filter, gearcase lubricant, fuel filters, plugs, water-pump parts, and storage supplies depend on the exact engine schedule, condition, and whether fall layup is included. HBW scopes the job from the serial number.

Can I skip a year to save money?

Follow the maintenance schedule for your exact engine and serial number. Deferring scheduled work can allow small issues such as contaminated gear lube, worn anodes, or seized hardware to go unnoticed, but the correct interval and parts list come from the Mercury schedule for your motor.

Mercury 100-Hour Service Cost in Ontario: What's Included (2026)

Search "100-hour service cost" and you'll get American answers: year-round boating states, different labour rates, different math. Here's the Ontario version. Many seasonal boaters reach the annual interval before they reach 100 running hours, so the scheduled service is...

Last reviewed: 2026-08-02

Mercury Premier Dealer·Gores Landing, ON·Quote builder available

Quick answer: There is no honest one-price answer across the Mercury range. The invoice depends on the exact engine, its serial-number-specific maintenance schedule, the parts due, its condition, and whether winterization is included. At HBW, fall work is first come, first served and there is no need to reserve winterization or storage capacity. Submit the service request about one to two weeks before your planned drop-off. Mid-November is the practical last call because the marina closes December 1.

Search "100-hour service cost" and you'll get American answers: year-round boating states, different labour rates, different math.

Here's the Ontario version. Many seasonal boaters reach the annual interval before they reach 100 running hours, so the scheduled service is often combined with fall winterization. Your Mercury owner's manual and the schedule for your exact serial number govern the interval and checklist.

That's not a dodge; it's the efficient way to buy it. One appointment, one drain of the same fluids, one bill.

Who this is for

You own a Mercury FourStroke, you've seen "100-hour service" in the owner's manual or heard it at the dock, and you want to know what the quote should account for. If you're deciding between doing it yourself and paying a shop, this covers that too. The interval rules themselves live in our Mercury maintenance schedule guide.

What a 100-Hour / Annual Service Actually Includes

The exact list varies by engine. Depending on the serial-specific schedule, a 100-hour or annual FourStroke service can include:

Engine oil and filter change
Gearcase (lower unit) oil change, with a look at what drains out (milky oil = seal problem caught early)
Spark plug inspection or replacement
Fuel system check: filters, lines, primer bulb, water-separating filter where fitted
Grease points, linkages, and corrosion check
Anodes checked, prop pulled and shaft greased
In fall, add the exact engine's fuel, internal-protection, battery, drainage, and storage-position steps

The bundling logic is simple: the annual service and winterization share most of the same labour. Doing them together is one bill instead of two.

Watch Mercury's official oil change walkthrough:

https://www.youtube.com/watch?v=ABeIIfXeB0Q

Video: Mercury 40-60hp FourStroke Maintenance: Changing Engine Oil (Mercury Marine official). The 75-300hp version is here.

What Determines the Cost?

A portable tiller and a large multi-cylinder outboard do not share the same oil capacity, filter set, spark-plug count, access time, or maintenance schedule. Four things shape the invoice:

The exact engine and serial number. This identifies the correct Mercury schedule and parts.
What is due. A routine annual service is different from a longer-interval service or a water-pump job.
What the inspection finds. Milky gear lube, damaged anodes, seized prop hardware, or a fuel-system concern changes the scope only after it is identified.
Whether fall layup is included. Annual service and winterization overlap, but they are not identical.

HBW scopes the job from the motor details on the service request. That is more useful than publishing one package price that fits some engines and misleads everyone else.

What moves the number up: skipped previous services, a water-separating filter that's never been changed, seized prop hardware, and anything the tech finds in the "while it's open" category. Our service-bill guide covers the habits that quietly inflate invoices.

Why "Cheap" 100-Hour Services Usually Aren't

A very low "full service" quote may simply describe a smaller scope. Compare the line items against the exact manual, especially the gearcase inspection and model-specific storage procedure:

Gearcase oil that comes out milky means water is getting past a seal. Caught at service time, it's a seal job. Missed for a season, it can be a gearcase.
Skipping the internal-protection procedure specified for the engine can leave storage-related corrosion or fuel-system problems.

Ask any shop for an itemized list before comparing prices. A lower quote may simply cover fewer maintenance items.

DIY vs Shop: The Fair Comparison

Plenty of owners handle oil and plugs themselves, and our DIY winterization guide doesn't gatekeep. The fair framing:

DIY saves labour and costs you the correct tools, supplies, disposal, and time.
The shop adds an inspection layer: the gear-lube check, condition notes, and a documented service record.
The hybrid many of our customers run: DIY the mid-season oil change, shop the annual fall service. The motor gets professional eyes once a year and you still save.

What we'd skip: DIYing the gearcase or internal-protection procedure if you cannot follow the exact manual. Those are two areas where a small mistake gets expensive.

What HBW checks before your motor goes back on the water

Every winterize-and-service at our shop ends with the tech recording recommendations on your file: what is wearing, what to watch, and what may need attention next season. The point is simple: scheduled fall maintenance gives you time to address a developing issue before launch season.

When Should You Submit an HBW Service Request?

You do not need to reserve a winterization slot or storage space months ahead. HBW has capacity, and fall work is handled first come, first served.

The common practice among our customers, and what we recommend, is to complete the service request about one to two weeks before your planned drop-off. That gives the team the motor details and requested work before the boat arrives without forcing you to predict your last boating day in August.

HBW is closed December 1 to April 1, so mid-November is the practical last call for fall winterization and storage intake.

Ready to Book Your Service?

Tell us the motor, its hours, and the work you want covered. Submit the request one to two weeks before your planned drop-off; for fall work, mid-November is the practical last call.

Service requests: hbw.wiki/service Phone: 905-342-2153 Address: 5369 Harris Boat Works Rd, Gores Landing, ON

Sources

Mercury Marine: FourStroke Maintenance
Mercury Marine owner manuals
HBW service and storage intake policy, confirmed August 2, 2026

Frequently Asked Questions

How much does a Mercury 100-hour service cost in Ontario?: There is no honest one-price answer across the Mercury range. Cost depends on the exact engine, its serial-number-specific maintenance schedule, the parts due, its condition, and whether winterization is added. Submit the motor details at hbw.wiki/service about one to two weeks before your planned drop-off so HBW can scope the right work.
Is the 100-hour service the same as winterization?: No. They can overlap, which is why Ontario shops often combine them. Scheduled service follows the exact maintenance table; winterization adds the model-specific fuel, internal-protection, battery, drainage, and storage-position steps. The scope varies by engine.
My motor only ran 40 hours this year. Do I still need the service?: Possibly. Mercury says most FourStroke outboards require an oil change annually or every 100 hours, and some other items have different intervals. Follow the owner's manual and serial-specific schedule rather than hours alone.
What parts get replaced at a typical annual service?: There is no one replacement list. Engine oil and filter, gearcase lubricant, fuel filters, plugs, water-pump parts, and storage supplies depend on the exact engine schedule, condition, and whether fall layup is included. HBW scopes the job from the serial number.
Can I skip a year to save money?: Follow the maintenance schedule for your exact engine and serial number. Deferring scheduled work can allow small issues such as contaminated gear lube, worn anodes, or seized hardware to go unnoticed, but the correct interval and parts list come from the Mercury schedule for your motor.
Do you service motors bought somewhere else?: Yes. HBW services Mercury outboards regardless of where they were purchased. Fall work is handled first come, first served; there is no need to reserve winterization or storage capacity. Submit hbw.wiki/service about one to two weeks before drop-off, with mid-November as the practical last call before the December 1 closure.

Harris Boat Works · 5369 Harris Boat Works Rd, Gores Landing, ON · (905) 342-2153

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