70 hp 3cyl. running problems

[aorford]

I have a 70hp 3cyl. merc. and the problem I am having seems like a fuel issue but not sure. Engine idles fine and revs ok in neutral but under load it starts dieing out. I rebuilt the carbs and fuel pump. I read it could be a stator or rectifier problem as well. I have noticed the batteries are not charging very well (12.2v). Compression is great across all cylinders. I also noticed a small oil film around the upper crank seal. Maybe sucking air through seal? Any suggestions would be great.

[boats.net]

Well air leaks can definately be a problem, as well as timing and carburetor adjustments. I recommend obtaining the service manual and verifying your adjustments. Start with idle/air mixtures, carb sync, then timing. While your at it test your stator/coils/rectifier-regulator.

[aorford]

I should also mention that it ran fine all summer and then it starting running that way all of a sudden with no change of any adjustments.

[boats.net]

Ok, well could be ignition or fuel. When your on the lake with a load check for spark when the motor boggs. If you never loose spark then problem should be fuel related.