by Brianna Collins
Image of three huge engines on a boat by Dev from Fotolia.com
Yamaha offers consumers a wide variety with its line of four-stroke outboards. In 2011 alone, the company introduced 10 different four-stroke brands with dozens of different models. Each had unique engineering specifications, power capabilities, and intended uses. But despite this wide variety between different models, Yamaha’s troubleshooting tips remain nearly identical for all of the company’s four-stroke outboards. Yamaha includes troubleshooting tips and specific part requirements in the owner’s manual for each of its outboards.
Use the starter motor on your Yamaha outboard. If the starter motor does not engage and the engine does not turn, the electrical system may be failing.
Check to see if the main fuse has blown on electric start models. To access the fuse, unscrew and remove the electrical cover on the top of the outboard and remove the fuse holder with a pair of pliers. If the connection in the center of the fuse is broken, the fuse has blown. Replace with one of the same amperage, as noted in the “Specifications” section of the Yamaha outboard owner’s manual.
Check the battery below. The battery should be located somewhere inside the watercraft, separate from the Yamaha outboard motor in a safe and dry place.
Disconnect the negative (black) cable first and the positive (red) cable second. Remove the battery from its housing.
Remove corrosion from the battery terminals with a wire bristle brush. Clean debris or other buildup with a solution of one cup of water and one tablespoon of baking soda. Dry the terminals well with a clean cloth before proceeding. If the battery is damaged, replace it.
Fully charge the battery with a separate power charger.
Reinstall the battery and battery cables, connecting the positive cable before the negative.
Retest the outboard starter motor. If the starter motor still does not activate, have a Yamaha certified mechanic inspect the electrical system.
Check the fuel system first if the engine is having trouble starting or running. Make sure there are adequate fuel levels in the gas tank. Otherwise, refuel with unleaded gasoline with an octane rating of 86 or higher.
Check the fuel lines connecting the outboard motor to the fuel tank. If breaks or leaks are found, immediately stop using the outboard motor and take it to the workshop for repair. If you find gummy or watery fuel, have a Yamaha dealer drain the fuel tank to remove the contaminated gasoline.
Next, check the engine oil levels. Make sure the outboard motor is upright and level. Then remove the oil fill cap and attached dipstick from the oil tank. Clean the dipstick with a cloth, reinsert it fully, then remove it and check the oil mark on the side of the dipstick. If the oil levels are below the “L” mark, refill the oil tank with SAE 10W-40 or SAE 10W-30 engine oil. If engine oil levels are above the “H” mark, remove excess oil with a clean syringe.
Remove and inspect the spark plugs. These are located inside the engine housing on each of the outboard engine cylinders. The exact type and number of spark plugs vary by outboard motor model; This information can be found in the “Maintenance” section of your Yamaha outboard owner’s manual.
Remove the spark plug cap and rotate each spark plug away from the cylinder with a spark plug wrench.
Replace spark plugs with burnt, brittle, or cracked insulator tips with the type specified in the owner’s manual.
Measure the spark plug gap with a wire feeler gauge. This gap should be within the range stipulated in the owner’s manual (usually around 0.028 inches). If it is too wide, shorten it by pressing the hook end of the plug against a firm surface. Expand the gap by pulling on the wider hook with a spark plug spreader tool.
Reinstall each spark plug …