Lower unit Trouble

Hello, I have a 1987 Yamaha 40LH that is giving me some trouble. At idle, the engine will push the boat. Anything above idle, the engine revs but no faster forward speed. Reverse works fine.

I took off the prop and with the engine off, and in forward drive, turned the prop shaft in the forward direction by hand.

It was fairly easy to turn by hand, but made a clicking noise in the lower unit as it rotated. Everyone keeps telling me prop, but I'm thinking it's the clutch dog or forward gear. Should the prop shaft even turn by hand when in gear????? It will not do this in reverse.

What are your thoughts?

[jb123]

hopefully your cable only needs a bit of adjustment, not fully engaging F .you should not be able to turn prop shaft while in gear, without turning over powerhead.

hopefully your cable only needs a bit of adjustment, not fully engaging F .you should not be able to turn prop shaft while in gear, without turning over powerhead.

Your gonna laugh at this one (this is my first boat ya know). It seems I was turning the shaft in the wrong direction. I was turning it clockwise in forward gear. The boat shop says I should be turning it counter-clockwise in forward.

Once I did that, I was unable to turn the shaft by hand, but could get a compression stroke with the prop back on but I could hear rubber squeaking. The service tech said spun hub.

Lower end problem

I have a 5 HP Yamaha that engages in forward only at low end rpms. Once I rev up to a certain rpm, the engine races and the prop disengages. Do I have a dog clutch or rubber bushing problem? or other problem?

[boats.net]

I have a 5 HP Yamaha that engages in forward only at low end rpms. Once I rev up to a certain rpm, the engine races and the prop disengages. Do I have a dog clutch or rubber bushing problem? or other problem?

Mark a line across prop washer and prop hub, run motor and recheck the line. If line is still aligned prop is ok, if not aligned prop hub is slipping and prop needs to be rehubed or replaced.

[rkmartin]

Sounds like the rubber hub in the prop needs to be replaced.