What's Biting: Make sure your four-stroke doesn't have a stroke

Until the early 2000s, anglers relied on two-stroke outboards to get them to where the fish were biting. Two-stroke engines are very simple and have a great power-to-weight ratio. Maintenance was relatively simple with a plug change, water pump impeller replacement and lower unit oil change.
However, as every fisherman with substantial time on the water will testify, a two-stroke may come apart without the hint of a warning. Running great one minute and dead in the water the next.

[caption id="attachment_5957" align="alignright" width="201"]Oil change Most manufacturers make oils for specific applications, but the owners manual may provide alternatives. Whatever you do, don't cheap out on the oil.[/caption]

Right around the turn of the century, Yamaha and Suzuki introduced four-stroke motors and the revolution started. The early four-strokes were heavy and lacked the punch of the two-stroke, but my have things changed in recent years.

The four-strokes have been refined so much that they are almost on par with the two-strokes in power-to-weight ratio, and the reliability has been greatly improved. That's not to say a four-stroke won't leave you calling for a tow, but it's less likely.

Of course, reliability also hinges on maintenance. For most people, the winter is the best time to get all the work done. Unlike two-strokes, where the oil was mixed with the gas, four-strokes have oil sumps similar to automobile engines. This requires oil changes at the interval (number of hours of running time) recommended by the manufacturer.

Check your owner's manual for the proper way to drain the old oil out of the engine without getting it everywhere. Change the oil filter, and then refill the engine with the proper oil. Most manufacturers make oils for specific applications, but the owners manual may provide alternatives. Whatever you do, don't cheap out on the oil.

Also change the oil in the lower unit by taking out the drain plug. Check the oil to make sure it's clear. If it looks milky, you're likely getting water past a seal, which may need to be replaced. You'll probably need your trusty mechanic to replace the seal unless you're pretty proficient under a shade tree. Be sure to take off the propeller to make sure there isn't any discarded fishing line wrapped around the prop shaft. If everything looks OK, refill the lower unit with the proper fluid.

The fuel system is next in line with the replacement of the fuel filter. Look for the fuel/water separating filter, and replace it with a new 10-micron canister.

If at all possible, use gas without ethanol in your outboards. There are several gas stations along the Gulf Coast that have boat gas, although the ethanol-free version is somewhat higher. If you have no alternative other than using gas with 10-percent ethanol, be sure to treat the fuel with a stabilizer that will keep the ethanol from separating from the gasoline. If the stabilizer wasn't added before the boat was last used, be sure to run the outboard for a few minutes to distribute the stabilizer through the fuel system.

Find all the grease fittings on the outboard, and pump in a few shots of fresh grease. Remove the batteries if the boat will be stored for the winter, and keep them charged in a dry place off of a concrete floor.

Make sure you trip your outboard all the way down to drain out all the water out of the cooling system, and you should be ready to reinstall the batteries, and head out for a fun day of fishing in the spring.

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David Rainer Blogger
David Rainer (1 Posts)
David Rainer has written about the great outdoors on the Alabama Gulf Coast for more than 20 years. For 14 of those years, he covered the many fishing opportunities on the Gulf Coast as outdoors…