Do you need to troubleshoot your Yamaha, Suzuki, Honda, Evinrude, or Mercury outboard? Even though most of today’s outboard engines require a full-blown laptop scan to diagnose, some common problems can be addressed rather easily… if, that is, you know what to look for.
Electrical issues and the number one problem, when your outboard won’t start. To make sure you have enough juice to get it running, tilt the engine up and down one time. If it doesn’t run full speed, you may not have the power you need. (Check your battery cable connections, and scrub away any green crud before going any further; it’s enough to prevent the power from getting through to the engine.) If it does, immediately suspect the shifter. Jiggle it a bit as you turn the key, to make sure it’s in the proper neutral position. Next check the kill switch, which may have shorted. You can circumvent it by disconnecting the black wire with a yellow stripe, at the ignition switch.
Fuel systems come next in the troubleshooting line up. Pump the ball to make sure it’s firm, not collapsed (which indicates a vacuum, check the vent and vent line(s) to make sure they aren’t kinked or blocked) or soft (which indicates a leak in the system.) If all’s well there, suspect ethanol issues. Do you add Star Tron to your tank on every fill-up? If you don’t burn the fuel out of your boat at least every few weeks, you should. Sudden shut-downs and bogging means you probably have a significant amount of water in your fuel tank.
Finally, consider the cooling system. If you’re overheating or the tell-tail isn’t flowing there’s a good chance the intakes are blocked (check them for plastic bags, weeds, mud, etc.), or your impeller has gone bad. (You’ll have to replace it.) If the impeller proves okay, than the thermostat is the next most likely culprit; put it in a pot of boiling water to see if it’s opening properly.
Two other easy to spot and common issues are vibrations, due to a bent or chipped prop; and vibrations or a thump upon acelleration, due to loose motor-mount bolts. Of course, there are plenty of other problems you’re likely to encounter while running an outboard that require the help of a pro. But often these easy issues can be identified, with a bit of quick troubleshooting.