MerCruiser Technical Information FAQs

How can I find my closest authorized MerCruiser dealer?

Authorized MerCruiser dealers in the United States and Canada can be found under Find a Dealer on this website.

Links to regions outside of the United States and Canada can be found on the Contact Us page.

What are the specifications for my MerCruiser engine?

A general listing of specifications is included in our MerCruiser product section. Your Operation, Maintenance & Warranty manual also includes some specifications. Additional technical information can be found in the appropriate Service manual for your engine model, or you can check with your local authorized MerCruiser dealer.

Where can I get factory Service manuals, Parts manuals, or Operation, Maintenance & Warranty manuals?

You can order all available literature online. You could also order all literature through any authorized Mercury dealer. Please have your outboard or sterndrive serial number before placing the order.

I need to replace my existing engine. What are my options?

Due to the large number of different engine/boat configurations and the changes made to engine packages over the years, we suggest you contact your dealer, engine power center and/or boat manufacturer for specific guidance in your case. Information on repower options is available in the Repower section of this Web site.

How do I obtain horsepower curves, torque curves, or fuel consumption data?

Horsepower and torque curves are not published because they are considered confidential company information. Fuel consumption data is not published because it is affected by factors beyond our control, such as boat hull type, temperature, humidity, altitude, gear ratios, propeller, etc. In some cases, fuel consumption or other performance data is available from your boat manufacturer for a specific boat/engine combination.

Some engine test data is available in the Engine Test section of this Web site.

I want to upgrade to a new-style sterndrive with my existing engine and transom. Is this possible?

There are many factors which determine the proper sterndrive for a given engine. A different sterndrive may physically bolt to your existing transom assembly, but it may not be a good match for your engine and boat. An Alpha Generation II sterndrive will not fit where an R/MR/Alpha I drive was used. Alpha and Bravo series sterndrives cannot be interchanged. In some cases it is possible to interchange members of the Bravo drive family. We recommend contacting your dealer or engine power center for specific guidance before undertaking any type of sterndrive replacement, upgrade, or repower. Information on repower options is available in the Repower section of this Web site.

I want to upgrade to a newer engine and use my existing sterndrive and transom, what will work?

There are many factors involved in replacing your marine engine; newer current engines will not directly backfit to older style sterndrives and transoms. We recommend contacting your dealer or engine power center for specific guidance before undertaking any type of engine replacement, upgrade or repower. Information on repower options is available in the Repower section of this Web site.

I want to upgrade to a more powerful engine. How much more performance can I expect?

This depends on many factors such as hull type, weight distribution, maximum horsepower rating of the boat, etc., and cannot be accurately determined without more information. We suggest you contact your dealer, engine power center, or boat manufacturer for specific guidance in your case. Information on repower options is available in the Repower section of this Web site.

On a hot day after I run the engine for a while then shut down, the engine won't restart or it starts and idles fine, but when the throttle is advanced the engine bogs down or quits running and will not restart. Why?

It sounds like your engine may be vapor locking. One factor that contributes to vapor lock is fuel. Fuels produced for use during the winter and early spring months around the United States are designed to vaporize at a lower temperature. This lower vaporization point can cause the fuel in the boat supply lines and engine fuel system to vaporize prior to being used. Another contributing factor to vapor lock is a restriction in airflow into the engine compartment. Make sure that lifejackets, fluid containers or other equipment have not restricted the airflow.

Other items that will help to reduce vapor lock are:

  • Letting the engine idle for 3-5 minutes before shutting it off. 
  • Opening the engine cover to let the hot air escape. Note: Always reinstall the engine cover before starting the engine.
  • Operating the bilge blower to remove the hot air.

If these items are OK, an authorized MerCruiser dealer can perform additional tests on the fuel and ventilation systems.

Can I use an automotive longblock or shortblock to replace my MerCruiser engine?

No, an automotive block cannot be used for several important reasons. The MerCruiser ECMs (electronic control modules) are specifically calibrated to each of our engine models. It would not be possible to determine the effect on the performance or compatibility with an automotive engine. In addition, automotive engines are not equipped to endure the high rpm duty cycles and harsh environment that marine engines see. Further, some of our engine components are unique to marine engines, such as the welch plugs, camshafts, cylinder heads, head gaskets and pistons.

My engine diesels, or runs on, after it is shut off. What causes this and can it be eliminated?

Under certain conditions, carbureted engines may "run on" after the ignition key is turned off. This condition is rarely caused by a defect in the engine itself. Usually, a combination of external factors is responsible. These factors include, but are not limited to, the type and formulation of fuel used, the boat's engine compartment ventilation system, ambient air temperatures, excessive engine compartment temperatures, how quickly an engine is shut off after running at cruise or higher rpms, elevated engine idle rpm setting, use of spark plugs with an incorrect heat range, deposits on the spark plugs or in the combustion chamber, etc.

There are some things you can do to minimize a "run on" condition. Most importantly, allow the engine to idle for a few minutes before shutting it off. This helps the engine to normalize at idle rpm. Other suggestions include having your dealer verify the engine idle mixture, idle rpm and timing are correct. Try a different brand of regular fuel or try premium fuel. Use spark plugs that are in the next colder heat range. Most of these are changes that should be made by your local authorized MerCruiser dealer. Our company has provided information to authorized dealers to help them assess your situation and to correct or adjust the contributing factors.

The paint on the top of my sterndrive is dull and seems to have some type of deposit adhering to it. How can I make it look nice again?

The dullness comes from mineral deposits in the water. When the boat is on plane, the top portion of the sterndrive is out of the water. As the water evaporates from the top of the sterndrive, it leaves behind mineral deposits. You can remove them by using a liquid cleaner for bathroom tub and tile, followed by a coat of wax to help protect the surface.