Yamaha 70B - Service Manual

Other manuals for Yamaha 70B

Owner's Manual222 pages

Questions and Answers

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zcrawfordAug 3, 2025
Why Yamaha 70B starter will not operate?
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  Billy JordanAug 3, 2025
  If your Yamaha Outboard Motor's starter won't operate, several factors could be at play. The battery capacity might be weak or low, requiring you to check its condition and potentially use a battery with the recommended capacity. The battery connections could be loose or corroded; ensure you tighten the battery cables and clean the terminals. A blown fuse in the electric start circuit could also be the culprit, so check for any electric overload, repair it, and replace the fuse with one of the correct amperage. Other potential causes include faulty starter components (have these serviced by a Yamaha dealer), the engine stop switch lanyard not being attached (attach the lanyard), or the shift lever being in gear (shift to neutral).
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James PierceAug 12, 2025
What to do if Yamaha 70B Outboard Motor engine will not start but starter operates?
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  Cindy WhiteAug 12, 2025
  If your Yamaha Outboard Motor engine won't start but the starter operates, here's what to check: The fuel tank may be empty, so fill it with clean, fresh fuel. The fuel could be contaminated or stale, requiring you to replace it with clean, fresh fuel. A clogged fuel filter needs cleaning or replacement. Make sure you are using the correct starting procedure. Inspect, clean, or replace fouled or incorrect spark plugs with the recommended type. Ensure spark plug caps are correctly fitted. Check for wear or breaks in the ignition wires, tighten loose connections, and replace worn or broken wires. Also, attach the engine stop switch lanyard and shift to neutral. For fuel pump malfunctions, faulty ignition parts, damaged engine inner parts, have it serviced by a Yamaha dealer.
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David ParkAug 16, 2025
How to troubleshoot a Yamaha 70B Outboard Motor when the starter will not operate?
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  Alex RichardsonAug 17, 2025
  If the starter on your Yamaha Outboard Motor won't operate, begin by checking the battery. Ensure it's in good condition and has the recommended capacity. Tighten any loose battery cables and clean corroded terminals. Inspect the fuse for the electric start circuit and replace it if blown, after addressing the cause of the overload. Ensure the engine stop switch lanyard is attached and the shift lever is in neutral.
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John ShepardAug 29, 2025
How to fix excessive vibration in Yamaha 70B Outboard Motor?
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  sharon25Aug 29, 2025
  Excessive vibration in your Yamaha Outboard Motor can stem from several issues. A damaged propeller should be repaired or replaced. A damaged propeller shaft or steering pivot requires servicing by a Yamaha dealer. Remove any weeds or foreign matter tangled on the propeller. Check for and tighten any loose motor mounting bolts. Also, tighten or have serviced a loose or damaged steering pivot by a Yamaha dealer.
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Mrs. Kristen HollandNov 7, 2025
Why does the warning buzzer sound on my Yamaha 70B?
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  kayla95Nov 7, 2025
  If the warning buzzer sounds or the indicator lamp lights on your Yamaha Outboard Motor, it could be due to several reasons. The cooling system might be clogged, so check the water intake for any restrictions. The engine oil level could be low, requiring you to fill the oil tank with the specified engine oil. An incorrect heat range of the spark plug necessitates inspecting and replacing it with the recommended type. Ensure you are using the specified engine oil and replace it if it's contaminated or deteriorated. If the oil filter is clogged or the oil feed/injection pump malfunctions, have it serviced by a Yamaha dealer. Improper load distribution on the boat can also trigger the warning, so distribute the load evenly. Lastly, a faulty water pump or thermostat should be serviced by a Yam...
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Misty PetersNov 19, 2025
Why is my Yamaha Outboard Motor losing power?
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  Allison MontgomeryNov 19, 2025
  If your Yamaha Outboard Motor engine experiences power loss, several factors could be responsible. A damaged propeller should be repaired or replaced. An incorrect propeller pitch or diameter requires installation of the correct propeller to operate the outboard at its recommended speed range. Adjusting the trim angle can help achieve more efficient operation. If the motor is mounted at an incorrect height on the transom, it should be adjusted to the proper transom height. Additionally, check for warning system activations and correct their causes. Clean the boat bottom if it's fouled with marine growth. Inspect, clean, or replace fouled or incorrect spark plugs, remove any foreign matter tangled on the gear housing, and clean the lower unit. Obstructions in the fuel system, a clogged fuel...
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Jason McphersonNov 24, 2025
Why does my Yamaha 70B Outboard Motor idle irregularly?
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  gmccoyNov 24, 2025
  If your Yamaha Outboard Motor engine idles irregularly or stalls, several factors could be the cause. Start by inspecting the spark plugs and cleaning or replacing them if they are fouled or of an incorrect type. Check for any obstructions in the fuel system, such as pinched or kinked fuel lines. Ensure the fuel is clean and fresh, and replace the fuel filter if it's clogged. Other potential issues include failed ignition parts, which should be serviced by a Yamaha dealer; activation of the warning system, requiring you to identify and correct the cause; an incorrect spark plug gap, which should be inspected and adjusted; and poor connections or damaged ignition wiring, which should be checked and repaired. Also, be sure that you are using specified engine oil. For thermostat issues, carbu...