Engine running uneven - Carb leak and/or spark plugs

N

nathangill

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Jul 29, 2004
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I have a 1984 75hp Johnosn Outboard (J75TLCR). I just rebuilt the 3 carbs and used new seal kits. Now, the top carb is leaking fuel from idle to about 2000rpm. It seems to be spraying out of the small holes at the top of the carb barrel which are controlled by the low speed needle. Is this a float problem? I replaced the floats, needles, and seats and have the float adjusted so that the end away from the hinge is about 1/32" higgher than the hinged side. <br /><br />I have Denso W27FS-U10 spark plugs in the motor. Is it a problem that I am not using the recommended champion plugs? The motor is running a little uneven, but I didn't know if that is due to the leaky carb or the plugs.
 
JB

JB

Honorary Moderator Emeritus
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Mar 25, 2001
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Re: Engine running uneven - Carb leak and/or spark plugs

Moving to Johnson Troubles.
 
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Dhadley

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Feb 4, 2001
Messages
16,978
Re: Engine running uneven - Carb leak and/or spark plugs

I wouldnt think its a float problem as that setting will close the needle sooner than what OMC called for if youre setting the float with the carb turned upside down. Not sure I'd do it that way. It means theres less gas in the bowl and we stand the possibility (although slight) of running lean.<br /><br />The other thing is I'd highly recommend getting the right Champion plugs in there. Those motors arent as sensative about combustion temps as the newer big bore 3 cylinders but why risk it? <br /><br />Running lean with an improper heat range could lead to bad things happening.
 
N

nathangill

Recruit
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Jul 29, 2004
Messages
3
Re: Engine running uneven - Carb leak and/or spark plugs

I changed the spark plugs over to the recommended Champions and had the boat out this weekend. At high speeds, it runs better that it has in more that 10 years.<br /><br />Idle still needs a little work. The top carb is spraying fuel back towards the air cover when at idle. Is it too righ? I have the needles out at 2 turns. Any thoughts on what might cause this?
 
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