MarineEngine.com does not offer troubleshooting assistance or repair advice by email or by telephone.
You are invited to join our public Boat Repair Forum to seek assistance from other members.
You may also visit the Boat Motor Manuals section of our site to obtain a service manual.
You should start by testing the compression. PSI should be within 10% of each other in both cylinders.
Then; test spark. Should jump at least 1/4" gap.....7/16" if you have electronic ignition. Don't just look at the spark plug gap; use a spark tester. They cost about $7.00 at auto-parts stores.
Could the carb be dirty? It sure could! Clean the main jet and the needle and seat areas at a minimum...and check float level.
I like those motors. That model is way better than most of Sear's offerings over the years.
Have you checked to see that the carb butterfly is completely horizontal when you advance the throttle to WOT?
Also...check the mag plate and it's it's linkage to be sure that it's advancing all the way....