1970 65hp johnson won't start

papasage

Senior Chief Petty Officer
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Jan 12, 2003
Messages
785
Re: 1970 65hp johnson won't start

change plugs . maybe hitting to much gass and foweled them . check compression . you need thim all 3
 

jim dozier

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Jan 8, 2003
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1,970
Re: 1970 65hp johnson won't start

An engine needs 4 things to be right to run<br />1. Strong spark<br />2. Proper timing of spark<br />3. Proper compression<br />4. Proper mixture fuel/air<br /><br />You say you have spark and fuel. If that were the case and the timing was OK and the compression were OK we wouldn't be here having a chat.<br /><br />How do you know you got spark and fuel? What is the compression on your engine? When was the last time it ran and what has happened since?
 

jparker70

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Feb 3, 2003
Messages
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Re: 1970 65hp johnson won't start

IT LAST RAN ABOUT A MONTH AGO. IT HAS NEW SPARK PLUGS.(LESS THAN TWO MONHS OLD BUT I WILL CHANGE THEM.) I THINK I HAVE FUEL BECAUSE WHEN I PULL THE PLUGS OUT THEY WET WITH GAS. AND BLACK ON TOP.<br />WITH THE PLUG OUT YOU CAN SEE THE ARC JUMP.<br />I WILL CHECK THE COMPRESSION ON THEM.
 

jim dozier

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Re: 1970 65hp johnson won't start

Sounds like it may be flooded. Just to make sure its getting fuel I would squirt some pre-mix in the carb throats (take off the airbox if there is one). If its not getting fuel that will fire it. If it is flooded now it will be really flooded. Take out the plugs turn it over a few times and let it air out for a couple of hours. Disconnect the fuel hose and try again. If it fires up check to see if fuel is puddling or leaking out of the carbs you may have a stuck open carb float valve.
 

jparker70

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Feb 3, 2003
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Re: 1970 65hp johnson won't start

JIMD<br /> I TRIED THAT AND IT DID NOT FIRE. SOME ONE TOLD ME THAT MY WOODRUFF KEY IN UNDER THE FLY FLYWHEEL COULD BE SHEARED.?? HOW HARD IS HTE FLY WHEEL TO REMOVE. I DO HAVE A PULLER.
 

jim dozier

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1,970
Re: 1970 65hp johnson won't start

Its not hard but you will need the puller. Make sure you torque the flywheel nut back on to the proper specs, they are usually torqued on pretty tight.
 

ajp

Petty Officer 1st Class
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Jan 6, 2002
Messages
280
Re: 1970 65hp johnson won't start

Get a service manual first. Go through the troubleshooting checklists. It is not likely for the key to be sheared.<br /><br />Start over with "NEW" plugs. Crank the starter for 1 second with the plugs out to expel any remaining fuel. Put in new plugs. Start engine. Slowly add fast idle and choke. If it ran before, it will start.<br /><br />If it is flooding, you have no, weak, or intermittant spark.
 

jparker70

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Joined
Feb 3, 2003
Messages
27
Re: 1970 65hp johnson won't start

changed the plug it did start but will not idle. <br />the bottom plug was black after only a few seconds of running.
 

JayM001

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Jun 13, 2007
Messages
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Re: 1970 65hp johnson won't start

If you do pull the flywheel be sure to use an OMC puller - don't use an automotive puller because you may crack the flywheel if you do. The OMC item can be purchased thorugh the parts dept. at your local OMC dealer.
 
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