Outboard Motor Oil

In the last couple of blogs, we’ve covered some basic fuel and oil questions in regard to boating.  One frequently asked question that was not previously addressed was, “I have some outboard motor oil that has been sitting on the shelf for a few years.  Is it any good?  Can I still use it?”

The answer is:  shake it up a bit and it should be fine.  It may need to be room temperature to perform at its best, so avoid extreme heat or cold.

What is oxygenated fuel?   Oxygenated fuel contains oxygen as part of its chemical makeup.  The purpose of fuel oxygenation is often to reduce carbon monoxide levels created while the fuel burns.  Usually oxygenates come in the form of gasoline additives, such as alcohol.

Some boaters are concerned with the possibility than an oxygenated fuel can harm their motor and interfere with the performance of their outboard motor oil.  Outboard motors can generally tolerate up to 10% alcohol content in fuels, which is the maximum amount allowed by the United States.

If it is a new motor, and it is attached to a new Evinrude boat (or a new-to-you boat), congratulations! You may have a question or two about the best care and feeding for this fine machine.  For instance, if you are dealing with a two-stroke Evinrude motor, you may be wondering what kind of oil to use. Their suggestions are XD30, XD50 and XD100 oil for two-stroke motors that are 1993 and newer.   When it comes to the grade of Evinrude outboard oil to use, 87 octane is the current minimum, but 89 octane is actually preferred.  Use of higher-octane fuels have not proven to provide any additional benefit, and may actually exacerbate hard starting conditions in hot weather.

If you are wondering about the proper ratio of fuel to oil for optimal performance in your Evinrude motor, a breakdown given on the company website is as follows: 1958 and prior used 20 parts fuel to 1 part oil; 1959-1963 used 24 parts fuel to 1 part oil; 1964 and newer use 50 parts fuel to 1 part oil.  High performance racing usage requires a ratio of 25 parts fuel to 1 part oil.  Finally, when it comes to gearcase oil type and capacity, refer to your owner’s manual for specifications. 

When choosing between a two-stroke or four-stroke outboard motor for your boat, the features of each must be considered.  Two-stroke outboard motors are lighter in weight, less expensive, and often faster.   They are generally easier to repair and maintain, having a comparatively simple design that has been available for almost 80 years. Two-stroke outboard motors tend to hold their resale value, remaining in high demand in the used market. On the con side, a two-stroke outboard motor produces more pollution, smoke, are non-two cycle oil injection models, have a rougher idle than their four-stroke counterparts, and are sometimes harder to start.

Four-stroke outboard motors are cleaner, quieter, smoother, provide more fuel economy, and are often more reliable.   They are preferred by some boaters who run in lakes and rivers because they are generally accepted at any body of water. They do not run on an oil and gas mixture or generate as much pollution.  The negatives of four-stroke outboard motors include their high expense for purchase and repair and heavy bulk, which makes it complicated to transport or position in storage without the help of a stand.  Because the design for a four-stroke outboard motor is more complicated than its two-stroke counterpart, there are more parts to malfunction.   However, outboard motor production will be either four-stroke or very similar. The technology for the four-stroke outboard motor is always improving, and as time goes on, there is a higher percentage of qualified mechanics to perform any necessary repairs.  The current used market is very limited for the four-stroke outboard motor, though this is also growing as technology and training improves. 

*Note:  this comparison does not include direct fuel-injected two-stroke models.

The best answer is… It depends. I/Os are the often the least expensive, and you have the advantage of having a realtively car like (simple) installation. You can get to the engine pretty easily in most boats. The disadvantages are that the outdrive can’t tilt clear of the water, so if you boat in saltwater the aluminum outdrive is always submerged and subject to corrosion. Also, the rubber bellows that encloses the drive shaft, as it comes out of the boat and into the outdrive is usually at least partly submerged. A hole, or tear, in it can sink the boat.

Read the rest of this entry »

Step 1:
Clean the bottom of your boat. Plant and barnacle buildup causes extra friction that burns additional fuel.

Step 2:
Remove excess weight from your boat. If you have a lot of heavy objects in the boat that you do not regularly use, simply remove them. This can account for as much as a 2 percent reduction in miles per gallon.

Read the rest of this entry »

The two stroke engine employs the crankcase as well as the cylinder to achieve all the elements of the Otto cycle in only two strokes of the piston.  A quality outboard motor oil like Evinrude XD 50 is more important than ever. 

Intake.  The fuel/air mixture is first drawn into the crankcase by the vacuum created during the upward stroke of the piston.  The illustrated engine features a poppet intake valve, however many engines use a rotary value incorporated into the crankshaft. Read the rest of this entry »