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View Full Version : 70hp Johnson cranks won't start


tichigan
08-23-2014, 07:27 PM
My motor started right up but when I gave a little gas to get the boat going the motor died. Now it will crank but not start. It HAS recently rained (just stopped ). Battery is strong starter strong. Old man next door says it could be coils cracked and shorting out from the moisture of the rain. Any suggestions?
pointer
08-23-2014, 08:56 PM
If the moisture was an issue it likely wouldn't have started.
Is the primer ball firm? Choke / primer ?

pointer
tichigan
08-23-2014, 09:19 PM
If the moisture was an issue it likely wouldn't have started.
Is the primer ball firm? Choke / primer ?

pointer

Ball is firm. Like I said yes it had started just before. Could it just be badly flooded?
flabum1017
08-24-2014, 10:36 AM
check for water in the fuel, spark and stop circuit. The stop circuit could be shorted in the key switch or lanyard switch. You can test both real quick by disconnecting the engine harness at the engine and jumping the starter solenoid....(make sure you have water hooked up for in case it starts) If it starts, then the problem is in the boat..... if it does'nt then the problem is in the engine
capnzee
08-24-2014, 12:20 PM
To fire, an engine needs oxygen, fuel, igniter. We can most likely eliminate the oxygen (air). Pull a plug or two and check to see if you have spark (ground the plug against the engine and turn the engine over with the starter looking for spark-in bright sunlight you may need to shade the plug to see the spark). If you have spark (igniter), blow the plugs out or replace them. Next is fuel, shoot some raw fuel/oil mixture in the carbs and crank engine--if you now get a pop or start out of the engine you are on your way to solving the problem. If you still get nothing, you may have a timing problem, eg. if the engine quit with a back-fire, you may have "spun" the fly-wheel and it may be time to see an outboard guru or start looking elsewhere as in the post above. First time out this year? Fuel tank left out in the elements? Could be water in the fuel--shoot some fuel into a glass and look for a separation of gas and water--milky type solution? Just happened to me--emptied the fuel, flushed the tank, refilled and engine runs perfect. Yep, it is a 70 hp OMC--these are wonderful old engines!