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.

Just as it is important to maintain your car’s engine for optimum performance, your boat requires a certain amount of care for consistent and smooth operation. Since an outboard motor hangs outside the hull of a boat, it requires special attention to prolong its life.  Caution when transporting your boat to the destination of your planned outing is extremely important.  The motor and boat trailer should be braced securely so that the motion of land travel does not cause permanent damage. 

Each time a boat is returned from a salt water excursion, the outboard motor should be flushed out with fresh water to prevent the pump and lines from corrosion.  Outboard motor oil and gas lines should be drained and disconnected before storing your boat for an extended period of time to keep the carburetor clean.  The area around the propeller and gears of the motor should be checked for cleanliness and excess water accumulation.  The pump inside the motor should also be checked to ensure the impellers do not look worn.  If all of these steps are taken regularly, your outboard motor should provide its best possible performance.

The viscosity of boat motor oil is one of its most important properties, as it measures how any given oil will flow.  Thicker oils will generally have a higher viscosity than thinner oils.  The viscosity of boat motor oil is essential for productive engine operation.

The numbers and letters on boat motor oil packaging refer to measurements that have been taken at specific temperatures.  A “W” means the oil meets viscosity specifications for winter use.  Multi-viscosity boat motor oils prevent the oil from thinning as it warms up because polymers have been added to prevent the oil from thinning.  It is wise to use multi-viscosity boat motor oil with the narrowest span of viscosity for the temperatures you will encounter—in the winter, for the lowest expected temperature, and for the summer, for the highest temperature anticipated. 

It may be sometime before the season ends, but you’ll want to read up on the precautions you need to take to ensure a long life for your boat.  Prior to the step below, Drain the gear case and check for excessive moisture in the boat motor oil.

Then, flush engine with fresh water using flush muffs or similar device attached to the raw water pickup. Let all water drain from the engine. Wash engine down with soap and water and rinse thoroughly. Disconnect fuel hose and run engine until it stops. It is important to follow a step by step process to make sure that all fuel is drained from the carburetor to prevent build-up of deposits from evaporated fuel. Use fogging oil in the cylinders to lubricate the cylinder walls and pistons. Apply water resistant grease to propeller shaft and threads. Change the gear oil in the lower unit. Lightly lubricate the exterior of the engine or polish with a good wax.

To understand how two cycle oil works in your engine, we need to cover some basic information on engine operating conditions and oil formulation. Outboard engines are characterized by their constant speed, high output operation. They are usually set at a desired high speed and continue at that speed until the destination is reached and then throttled down. Also, they are constantly cooled with fresh, cool, non re-circulated water.

Chainsaws, on the other hand, are a high action operation. They are constantly started and stopped, used for short periods, and frequent overloads are its hard place in life. Additionally, they have smaller displacements than outboards and are air cooled. By understanding how the operation of an engine can affect the oil used and how oil can affect the engine, we can better appreciate the difference between a water cooled two-cycle oil and one formulated for an air cooled two-cycle engine.

Just like with your car, boat motor oil leaks can signal a problem. Find oil leakage can be indicated in several ways, whether it’s a pool in your garage or driveway or if it’s mixed with water when you remove the water plug.  Here are some things you should look at to surmise a leakage problem:

• Check your dipstick before and after you take your boat out. It’s also good practice to do this anyway.
• Check if there’s oil in the oil pan.
• Check the level in your tilt and trim reservoir.
• Change your filter, if necessary.

If you’re still having issues, consult a professional boat mechanic to see if there are any other parts of the boat you may have glossed over.  The main thing is to solve this problem immediately before it causes a great deal of damage to your boat.

Don’t let the gloom and doom predictions of high gas prices keep you from your boating passion. Even with bulk oil costs soaring, it’s still possible to have some money in your pocket when you leave the fuel pier. By understanding your boat’s design - whether it has a displacement, semi-displacement, or planning hull - and doing some easy calculations, you will know the boat’s most economical cruising speed.

Displacement and Semi-Displacement Boats
Displacement hulls are designed to force their way through the water. A semi-displacement hull achieves a partial plane, which reduces drag and wave making. Both have a top speed that cannot be exceeded without increasing the power significantly. A large power increase also means greater fuel consumption.

To figure the maximum speed, multiply the square root of the waterline in feet times 1.34. Using this calculation for a 38 ft. displacement hull boat, the maximum speed is 9.2 knots. To save money on gas with a displacement or semi-displacement hull, do not try to increase your speed past the calculated maximum speed. In the case of the displacement hull, increasing power to go faster will use more fuel without a resulting speed gain. With a semi-displacement hull, your speed will increase, but there will be a corresponding fuel consumption increase.

Planing Boats
Pull back on the throttles with a true planing hull. Fuel consumption increases with every knot while the boat is on plane. A boat with a planing hull has the greatest fuel economy at the point when it first comes onto plane, or begins to skim the surface of the water.

Limiting the amount of time a planing boat displaces water before coming onto plane will also result in reduced fuel costs. This doesn’t mean slam the throttle downs to get up on plane faster. Instead, bring the boat up to speed at a moderately quick, steady pace.

If you are like me, you like to go fast quickly. But, if you follow these tips for reduced fuel consumption, you will finish at the end of the boating season having won the fuel marathon with a few extra dollars in your pocket.

Gas thieves aren’t just a problem on land. With the high price of gasoline, they’re also striking on the water.

Police are saying that they are receiving reports of gas cans being stolen and gas being siphoned from boats left tied to the end of docks or on boat lifts.

They’re reminding boat owners to remove gas cans and outboard motor oil when they secure their boats for the night.

Part of making your boat run well is to regularly change your oil filter. Ideally, you’ll want to change your outboard oil filter every 100 hours, or at the top of the season.  Here’s a guide on how to do it yourself:

• Because you’ll have to drain and then refill the oil, you’ll need to pull the boat out of the water onto dry land.

• Remove the engine cover, which is usually held in place with the use of one or two latches. Simply pull down on it and lift it straight up. Let it set off to the side — being careful not to scratch its surface.

• Here are some key parts and elements on the engine:

• Dip Stick — Simply pull it out to examine the condition of the oil inside the crank case.

• Fill — The fill for the engine oil screws on and off.

• Drain Plug — The manufacturer installed the drain plug for the crank case oil in what’s called the “mid-section” of the outboard engine. You simply loosen it to drain the oil.

• Before getting into the oil change, bring in a table and turn the steering wheel so that the drain plug on the motor is facing inward. Then trim the engine all the way up and place an oil pan on the table and under the drain plug.

• Back the drain plug out with the socket wrench, and be sure to have the oil pan right under the plug because the oil will flow freely.

• Once all of the oil has drained, wipe up any excess oil with a rag or absorbent pad.

• Replace the drain plug and tighten it securely.

• To change the oil filter, which needs to be changed every time to change the oil, you won’t be able to use a traditional oil-filter wrench because they’re too large. What you’ll need is a strap wrench that slips right over the filter cap. Pull it tight and then try to loosen the cap. If the strap slips, you may have to clean the filter cap with an absorbent pad. If this doesn’t work, get a screwdriver and hammer and simply drive (by tapping) the screwdriver tip down into the cap, and then rotate the filter until it becomes loose enough to take off.

• Before you replace the old oil filter with the new one, dip your finger into the old oil and rub a bead of the oil around the edge of the new filter’s gasket o-ring. This will make the job of removing this filter that much easier when it’s time to replace it.

• Screw the new oil filter into position.

• Now that the oil filter is in place and the drain plug is secured tightly, it’s time to remove the plug for the fill and add the three quarts of oil using a funnel.
• Warning: Every engine is different so be sure to check with the manufacturer’s manual for how much oil to use.

• The last thing you need to complete the oil and filter change is to pull out the dip stick in order to make sure you have enough oil. 

• Please always dispose of discarded engine oil at an approved collection center.