1972 50hp johnson losing 1 cylinder after startup

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irish122970

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I have a 1972 johnson 50hp outboard (50ESL72C) and the problem is that when it starts up it fires on both cylinders and then one stops. I have checked compression on both and get a good 150psi on each. I also checked the spark on both plugs ans both have a good solid spark. I purchased the motor about 3 weeks ago and I am not very knowledgeable about outboards. Do you think the gas that was in the tank when I purchased it could have been old and would cause these symptoms? Could the 2 carborators cause this if they are not fully clean....Just not sure what to do next and I do not really want to dump a pile of money into the motor.
Any input would be appreciated....
 
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w2much

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Re: 1972 50hp johnson losing 1 cylinder after startup

Certainly need to start with fresh fuel. Perhaps switch the coils if that does not help.
 
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irish122970

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Re: 1972 50hp johnson losing 1 cylinder after startup

w2much said:
Certainly need to start with fresh fuel. Perhaps switch the coils if that does not help.
Click to expand...

Ok, I will ckange the fuel for new. Also, I have already tried switching the spark plug cables with the same result.
Thanks
 
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Daviet

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Re: 1972 50hp johnson losing 1 cylinder after startup

If you drop one cylinder, and the compression and spark is OK, I would look at the carb for the cylinder that is dropping.
Maybe try squirting some fuel into the carb of the dropped cylinder and see if it picks up, if so you have a carb proplem for sure.
 
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irish122970

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Re: 1972 50hp johnson losing 1 cylinder after startup

Daviet said:
If you drop one cylinder, and the compression and spark is OK, I would look at the carb for the cylinder that is dropping.
Maybe try squirting some fuel into the carb of the dropped cylinder and see if it picks up, if so you have a carb proplem for sure.
Click to expand...

Thanks Daviet, I will try squirting fuel into the carb this wekend and report back. I have my fingers crossed lol
 
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