20 Reasons Why Your Boat’s Engine Won’t Start

boat engine

There’s nothing quite as frustrating as looking forward to getting out on the water only to arrive at the marina to find your engine won’t start. As tempting as it may be, resist the urge to keep cranking the ignition or you’ll end up draining your batteries and compounding the situation. Instead, consider the following list of twenty common issues for outboards, inboards and sterndrives that might be preventing your engine from turning over—chances are you’ll be able to fix one or more of these minor issues and be underway in no time!

Problem #1: Gas tank on “E.”
Solution #1: Fill ‘er up!

Problem #2: Gas tank air vent is closed.
Solution #2: Double check that the tank is properly ventilated by opening all vents.

Problem #3: Kinked or pinched fuel lines.
Solution #3: Ensure all fuel lines are free of obstruction and replace any that are damaged or frayed.

Problem #4: Water and dirt has infiltrated the fuel system.
Solution #4: Water will sit under the fuel in a distinctly-defined layer—if you see this separation drain the water and change the filter. If a significant amount of dirt or sediment has found its way into your tank, you might need to flush the system and re-fuel.

Problem #5: Clogged-up fuel filter.
Solution #5: Check filters for any obstruction or damage and remove any build up or replace if necessary.

Problem #6: Motor isn’t choked to start.
Solution #6: Ensure you follow the proper pre-ignition protocol for your specific motor—consult the engine manual if you are unfamiliar with the starting sequence.

Problem #7: Unprimed engine.
Solution #7: Similar to #6 above, ensure that your engine is properly prepped. 

Problem #8: Incorrect carburetor adjustments.
Solution #8: If the carburetor adjustments are too lean there will not be an adequate amount of fuel in order to start the engine. Re-adjust the settings and attempt to restart the engine. 

Problem #9: Motor timing and synchronization out of balance.
Solution #9: Unless you’re a seasoned mechanic, your best bet might be to call in a professional—there might be a damaged flywheel that needs replacing or other internal damage that can be quickly replaced.

Problem #10: Manual choke linkage is bent or damaged or auto choke is out of adjustment.
Solution #10: If there is only a slight bend or dent, you might be able to readjust it yourself with a pair of pliers or hammer—but if there is significant structural damage the part will have to be replaced in full. 

Problem #11: Faulty spark plugs.
Solution #11: If your spark plugs are improperly gapped, dirty, or damaged you’ll have a hard time getting your engine to turn over. Double-check your spark plugs and adjust or replace as needed.

Problem #12: Inoperative fuel tank primer.
Solution #12: If your boat features a pressurized fuel system, a misfiring primer might be the root of your engine-starting problems. Depending on the degree of damage, you might have to replace this component before going underway.

Problem #13: Offset ignition points.
Solution #13: Plain and simple – if your ignition points are improperly gapped, dirty or broken, your engine isn’t going to start. Make sure the connections are snug, free of dirt and grime and undamaged.

Problem #14: Frayed electric insulation.
Solution #14: Replace any visibly compromised loose, broken wire or frayed insulation segments or mend accordingly with electrical tape for a quick, temporary fix.

Problem #15: Reed valve issues.
Solution #15: If a reed is broken, fractured or missing it’s like having a hole in your engine and fuel cannot be properly delivered to the affected cylinder. On engines that feature check-valve bleed fittings within the intake manifold you might be able to put a pressure gauge on the bleed fitting and monitor the crankcase pressure to diagnose the source of the problem. Once you locate the faulty or damaged reed, it can be replaced with minimal hassle.

Problem #16: Weak coil or condenser.
Solution #16: You’ll most likely need to replace these worn-out components that commonly suffer from the overall wear-and-tear of frequent outings.

Problem #17: Cracked distributor cap or shorted rotor.
Solution #17: The distributor cap is an important part in the secondary circuit of the ignition system and must be in perfect condition to have a properly tuned engine. Even small cracks in the distributor, not always visible, will permit the high tension current to short circuit and prevent your engine from running smoothly. If you’ve factored out all other possibilities, this might be your problem—replace the component and give it another try.

Problem #18: Loose fuel connector.
Solution #18: Ensure all connections are snug and properly sealed before attempting to start your engine.

Problem #19: Safety lanyard or kill switch disconnected.
Solution #19: In all the pent-up excitement to get out on the water, you might have simply overlooked to disengage the safety lanyard or kill switch—don’t worry, it happens to even the most seasoned of sailors. Hide your blushes, disengage the safety features and be on your way. 

Problem #20: Dead batteries.
Solution #20: Check the voltage of your batteries. If they’re low, either recharge or replace the battery and attempt to re-start the engine.

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