No high rpms in forward

[LA.RICH]

I have a 1992 40 hp Johnson its on a pontoon the problem is only 1800 rpm's in forward gear when boat is tied to dock, about 2200 rpms wide open throttle moving. The motor operates fine on the trailer with flush attachment. This motor works fine in reverse. What i have eliminated so far is linkage,spark,fuel,plugs, and rectifier. Someone told me the prop hub might be spun. Any help or ideas will be helpful. thanks RICH

 

[ronward]

A spun prop hub would allow the motor to rev real quick. Motor would race but you would barely move. Just like you went to WOT while still in neutral. When's the last time the carbs were gone through? Is it bogging down or just not throttling up any higher?