My 86 yamaha outboard will not turn over

Remove Cowl ,Undo Four Bolts Securing Lower Cowl,Then Undo Bolts Securing Power Head, Disconnect All Attachments To Power Head From Cowl +any Electrical Connections ,Lift Power head Out

1. Fuel
   • A common problem with an easy solution, Yamaha boat engine trouble could arise due to inadequate levels of fuel or engine oil. All Yamaha outboards take unleaded gasoline as a main fuel source with a pump octane rating of 86 or higher. The type of engine oil varies according to motor size and can be found in the "Specifications" section of a particular outboard's owner's manual (See Resources).
     
   Electrical
   • Problems with the electrical system can also prevent a Yamaha outboard's engine from working correctly. Troubleshoot the electrical system, first removing the main fuse that's located underneath the electrical panel on any electric-starting outboard. If the connection at the center of the fuse is broken, it must be replaced by a fuse of the same amperage. The battery should also be removed, cleaned and fully charged when troubleshooting the electrical system.
     
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   Spark Plugs
   • Owners should also remove and inspect the spark plugs during the troubleshooting process. If the insulator tip of any plug is burned, that spark plug should be replaced. The number and type of spark plug depends on the specific outboard. Additionally, owners should ensure that each spark plug gap is set to the width stipulated in the owner's manual (see Resources).
     

check ur fuses

make sure you check the main fuse -- it sounds like the fuse is blown and needs to be changed.

c...

i have almost the same problem but mines a 98 5.0l vortec. the issue is i have no blown fuses but the truck runs low voltage all the time nothing above 12 volts. replaced the starter, alt, and starter hot wire. new battery. the starter relay was bypassed but it works just fine. idk what the deal is with this truck

first of all you have to see the low tension on the coil,and before that see what type of code is , because that maybe the key start

not enough information on the motor. what year and model? but all yamaha outboards are shut down by the C.D.I. being grounded by the key switch or the emergency kill switch. the cheapest thing to test or replace is the key switch and the emergency kill. with more info on engine I can help you further.

Hey the 80s celica's had a TSB problem concerning the starting of the cars, so it is a factory wiring problem, I have a 1988 celica and all I did was bypass the ignition with a high amp switch straight to the starter and to + on the battery, hope this helps.

Sound like the fuel pump is not keeping up with the engine's demand. Check it out. Good luck. Hope this helps.

On a plate below the powerhead on the shaft.