71 40 hp evinrude

R

rude 71

Cadet
Joined
Apr 29, 2012
Messages
7
hi i was wondering if anyone could help me out. my ob starts and runs , but only hits on one cylinder occasionally you can tell that its tryin to fire on the top. when i take the plugs out the top one is soaked. i have replaced everything with the ignition,coils points and condensers. could it be a carb problem, i cleaned carb but never rebuilt it. i have another post on here that goes in detail a little more of what i have done to it. but i was wondering if i could be flooding out top cylinder only. please help. thanks for any info.
 
oldcatamount

oldcatamount

Lieutenant Commander
Joined
Apr 4, 2010
Messages
1,740
Re: 71 40 hp evinrude

That sounds more like an ignition short in the top cylinder than a carb problem. Are the plug wires old? I'd check for a cracked wire or a loose connection from the coil to the plug on that cylinder. If you can, run the motor (on muffs) at night in your driveway. A short will be easier to spot in the dark.
 
oldcatamount

oldcatamount

Lieutenant Commander
Joined
Apr 4, 2010
Messages
1,740
Re: 71 40 hp evinrude

It might mean that you'll need to go back under the flywheel and have a look. I'd check the plug wire to coil connection, make sure you have adjusted the points right and you have tightened them down. Look closely at the condeser wire for chaffing on the bottom of the flywheel. Something is jiggling around giving you the intermittant fire and it may be very simple (once you find it).
 
R

rude 71

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Joined
Apr 29, 2012
Messages
7
Re: 71 40 hp evinrude

thank you so much i will try these things and let you know how i fair
 
R

rude 71

Cadet
Joined
Apr 29, 2012
Messages
7
Re: 71 40 hp evinrude

oldcat we checked the spark with a spark tester we have nice white blue fire and jumps a good gap 7/16" . you still think mabey the wires are lose?
 
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