I have a 70 hp johnson outboard, model number J70PLEE. It starts well, idles well, and normally hits top speed at about 37 mph turning around 5000 rpm. Yesterday it was cold...around 22 degrees F. The motor fired up, I let it warm up for about 5-6 minutes, and we headed up the reservoir like normal. I took it off plane and idled it around for about 10 minutes looking to mark some structure and then tried to put it under load again and all I could get was about 20 mph and 3000 rpm with the throttle wide open. The motor sounded a little different, but wasn't running rough. Did I lose a cylinder? and more importantly, how do I get it back?
I pulled the spark plugs when I got home and none were fouled or worn...I did notice that the plug out of the bottom cylinder appeared dry compared to the top two cylinders. I plan on changing the inline fuel filter, and picking up a compression tester to double check the compression in each cylinder, but I have suspicions that a carb clean-up is in order. Any other thoughts?
I pulled the spark plugs when I got home and none were fouled or worn...I did notice that the plug out of the bottom cylinder appeared dry compared to the top two cylinders. I plan on changing the inline fuel filter, and picking up a compression tester to double check the compression in each cylinder, but I have suspicions that a carb clean-up is in order. Any other thoughts?