Spinning the prop shaft manually as a test

[Hawkeye]

Odd question I suppose but how much effort should one need to spin a 2" prop shaft, 24" prop? Should it spin easily by hand, be somewhat difficult to spin, or be almost impossible to spin without a major effort? Can anyone give me an idea. Port side is difficult but the starboard side is almost impossible. I will shoot with a portable temp gun but wonder what is a good rule of thumb, expressed in effort or more precisely in temperature degrees.

 

[DavidM]

I have pulled at least a dozen props while the boat was on the hard and all moved easily or with moderate effort. Yours sounds like the shaft is out of alignment- does the resistance change as you turn it or the stuffing box is way too tight.


David

 

[rgano]

After checking your shaft seals as the possible cause, remove the shaft flange bolts to disconnect it from the tranny and then see if the difficult-to- spin shaft gets easier. If so, the engine alignment to shaft is off. If not, the the issue lies farther after and could be an issue with alignment of an external strut bearing and/or a cut-less bearing issue.

 

[SoWhat]

I would say mine are "firm"
I can turn them but I need grippy leather gloves.

Possible causes of tight shaft:
1) stuffing box too tight
2) shaft not aligned properly
3) shaft is bent
4) Strut is bent
5) rope around shaft at prop

Loosen packing nut; Check alignment with feeler gauge; Check straightness with dial indicator; Then disconnect coupling. If it's hard to turn while disconnected then you may have warped shaft, misaligned bearings, bent strut, etc.