I'm attempting to check the alignment of my engine with the prop shaft.
I am using a dial indicator - I have this crazy idea that accurate measurement will make the job easier.
The gearbox output flange appears to have substantially more play in it than the tolerance I was aiming for in the first place.
How much play would you expect in a gearbox output flange?
The gearbox is about 35 years old, the whole set up has had periods of bad vibration, so it is likely the bearings etc are a bit flogged.
I was hoping to get the alignment to within 0.125 mm, but currently seem to have a much greater margin of error on my measuring, i.e. the output flange has play in it.
Note, I suspect the current problem is with the propeller or shaft (most likely just barnacles on the propeller), but I wanted to start from the top and work through checking everything was correct with the alignment, including basic engine alignment (we use and R&D flexible coupling), both flanges are square on their shafts, the vertical alignment is correct, and if I can, see if there is any obvious bend in my shaft, before I have another go at the propeller.
We replaced the engine mounts a while ago and haven't re-checked the alignment after the initial install (which made a massive difference). We also replaced the cutless bearing, and I want to exclude any serious issues that would flog that out, like a bent shaft or completely unacceptable engine alignment. The current vibration feels like it is coming from the back of the boat.