Prop Walk, need a possible solution.

[Laguna 20]

I have a 1989 SeaRay Laguna 20' Center console, couple of years back I purchased a New 150 HP Mercury SeaPro outboard motor. Prop works great moving forward and gets me to the full rated RPM's at 5200.
Problem is when backing up it doesn't seem to respond correctly unless I'm going very slow, any throttle at all and it just goes straight it and doesn't respond. Someone told me it's "Prop Walk"
The original motor was a 200 HP Mercury 2-Stroke backing up at any speed provided great control, this prop was transferred to the new motor, per the dealer the prop would work great.

Where to I start to address this issues?

Jerry

 

[alldodge]

Does the new and old motor have the same length shaft?
Is the Cav plate and prop below the keel?

 

[jimmbo]

Perhaps the Exhaust, which Exits thru the Prop, is causing the Prop to loose its Bite when you rev it up in Reverse

 

[Chris1956]

I thought prop walk was when the boat moves to the side of the "hand" of the prop. i.e. in forward with a right hang prop, the stern will move to the right a bit.

Does the motor (swivel) steer the same amount in both directions? Sometimes they turn a lot more in one direction, due to improper dealer or owner set-up.

 

[dingbat]

My neighbor had the same issue when the marina mounted a new 20" shaft outboard on his 25" transom boat.

Other than that, a very common issue on a bracketed boat since the thrust hits the transom.

 

[garbageguy]

consider the prop's angle to the water line with the old and new motors when backing