QC4 Refresh

The Mercury Racing QC4 Factory Refresh program, based at our world headquarters in Fond du Lac, Wisconsin features a complete inspection and refresh of the engine by the same technicians…the experts – who built it originally. The entire long block is exchanged with a factory certified core assembly or a new long block, when needed.


Fresh to the Core

Mercury Racing technicians work their magic, starting with a bare cylinder block to build the QC4v core exchange long blocks. The crankshaft and all other rotating components are washed and magnafluxed to ensure the metallurgy’s integrity. After the long-block assembly has been refreshed, it goes through Mercury Racing’s electrostatic, high-solid, polyurethane paint process to bring the engine back to like-new condition. Each engine endures a complete dynamometer run prior to being released and sealed as certified Factory Fresh. All parts purchased by the customer, including the long block, come with a Parts and Accessories Warranty that matches the original factory warranty.

Process Overview

Process begins by contacting your OEM boat builder or Mercury Racing dealer to return your engine(s) for refresh.

Process Highlights

  • Rebuilt by Mercury Racing Technicians
  • Factory original parts
  • Choose either a new or a reconditioned long block
  • Qualified on Dyno – full power run and system check
  • Factory warranty on all purchased parts for non-competition (1100-1550) models

QC4v Refresh & Maintenance Interval Schedule

Model Refresh Time Maintenance Intervals (Hours)
Max Hours Valve Lash Oil Change
860 300 100 50
1100 200 25/75^ 25
1350 200 25/75^ 25
Dual Cal 1350/1100 200 25/75^ 25
1550 25—100* 25/75^ 25

*Maximum hours for refresh at 1550 mode is 25 hours; a total of 100 hours when combined with 1350 mode run time.

^Recommended adjusting the valve lash after the first 25 hours and every 75 hours afterward


Why should I send my QC4v engine back to Mercury Racing for refresh?

You made a significant investment in becoming one of an elite circle of owners with your purchase of Mercury Racing QC4v engines.  The best way to protect your investment and ensure maximum reliability, durability, and performance from your QC4v product is by having the same technicians – the experts – who built your engines; perform the refresh right at the Mercury Racing factory. In addition, you can feel confident knowing all replacement components are genuine Mercury Racing factory original parts.  Best of all, having your refresh work done at Mercury Racing means you receive a 1-year factory warranty on all replacement parts.

How do I return my engine to Mercury Racing?

All QC4v refreshes are processed through Mercury Racing dealer and boat builder partners. Simply contact your dealer or boat builder who will initiate the refresh authorization paperwork. Your dealer or boat builder will handle return shipment of your engines back to the Mercury Racing plant.

How long will the refresh take?

A typical QC4v refresh takes about 2 to 3 weeks from the time the engines arrive at Mercury Racing to the time they leave our plant.

What is the time involved in a typical refresh?

A complete refresh takes about 145 man hours from start to finish with multiple Mercury Racing team members working throughout the process.

Is the refresh service covered by a warranty?

Yes.  All replacement parts (including the long block assembly)are covered by a 1-year factory warranty.

What all is inspected during the refresh process? Which components are refreshed vs. replaced?

Component Inspected Refreshed Replaced
Cylinder Block
Connecting Rods
Oil Pump
Sea Pump
Connecting Rod Bolts
Pistons and Rings
Valve & Valve Springs
Valve Train Keepers & Retainers
Valve Guides As needed
Valve Seats 2nd Refresh
Timing & Accessory Drive Chains
Tensioner Guides
Primary Drive Sprocket
Exhaust Log
Heat Exchanger
Gaskets, Seals, Belts & Hoses

How does Mercury Racing refresh a cylinder block?

Cylinder blocks are first cleaned ultrasonically. Cylinders are stripped and replated as needed.  All cylinders are honed to ensure proper sizing and a good seat for the new piston rings.  Long blocks also get a fresh coat of paint as part of this process.

What does Mercury Racing look for during inspections?

During inspections, crankshafts and connecting rods are magnafluxed (a type of high tech x-ray) to ensure sound metallurgical integrity inside and out. In addition, exhaust logs and heat exchangers are inspected and pressure checked for leaks, and replaced at the customer’s expense if necessary. Finally, turbos are disassembled and inspected to ensure the integrity of the rotor bushings and blades.

What happens when a part cannot be reused?

Long block components (cylinder block, cylinder heads, crankshaft, connecting rods, camshafts and other internal components) that are not reusable are replaced at no additional cost to the customer. Dress components such as starter motors, alternators, etc., that are not part of the long block are replaced at the customer’s expense if they are not reusable.

Is the engine run prior to leaving the Mercury Racing plant? 

Yes. The refresh includes a 2-hour run time on the dynamometer, which includes a break-in period and full power run. The valve lash is checked and all cylinders are inspected via bore scope prior to being approved for return shipment to the customer.

Does Mercury Racing refresh transmissions?

Yes. There is an option to have your QC4v transmission refreshed at Mercury Racing while your engine is at our location for its refresh.  When you initiate the refresh process with your dealer or boat builder, please be sure to advise them at that time that you would like the transmission refreshed in addition to the engine itself.

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