[THEFERMANATOR]

Did you pull the carbs and clean em? If not do so soon. 3 years will have alot of gunk in them if they sat with any fuel at all in them. Also check to make sure your timing is advanceing properly. The MERC's are known to not reach full timing once they have sat for awhile. The plastic on the pickup harness gets hard and will prevent it from advanceing all the way. Make sure all of your linkage is clean and free and well lubricated, put some new plugs in it, and make sure the carbs are clean.

The 135 is the same engine as a 150 internally, just different carbs. And a 135HP should be propshaft rated as they didn't come out until the mid 80's when they switched the rating's. An early 80's 150 became a 135 in the mid 80's, and the 175 became a 150. The top end numbers should be pretty close to that of a 150 as that 135 has good torque for it's size. Make sure you hit the right RPM's at WOT as they are affected by propping and engine height fairly easily.