mercury 150 blackmax wont plane out

[Mark7]

my mercury wont plane out. I have changed the prop from a 23 inch 4 blade to a 21 inch 3 blade and it still wouldn't plane out. it wont even pick up speed till you walk to the front and plane it out. cant figure out what to do next??

 

[faztbullet]

Check spark and compression as sounds like its only running on 4 or 5 cylinders. If ok check carbs....

 

[fastjeff]

You might still have too much pitch. My friend's boat had a similar problem (same motor).

Jeff

 

[MikDee]

Check your "link & synch." throttle opening, plus full spark advance on the linkage, make sure they're both moving fully to their respective stops.