After owning my last boat with a Volvo DP for a few years, it would occasionally take a second or two to go into gear, especially from neutral to forward. This would never happen when the engine was cold, but only after it ran for awhile.
Not too cool if you are trying to dock it.
It only happened a few times, and I ended up getting rid of it when I got my current boat before I figured out what was going on. It felt like the delay was related to the cable, as it felt kind of "muddy" - which is about the best I can describe it.
Typically the cable system tends to snake around the boat - you should see my current boat - the cables are probably 30ft long, and each goes through at least 540 degrees of direction change.
Things I can think of are; stiff cable due to too many bends, stiff cable due to a dirty cable, or possibly a faulty installation with too tight of a bend that could create a trouble-spot as the boat ages.
While this is not from Volvo, I looked at the documentation for my Teleflex shifters. There is no mention of lubrication as a maintenance issue, so I am not sure if this would be possible.
The only thing I could find is the mention of a bend radius in the cables of not less than 8". Since production boats are sometimes designed and constructed haphazardly, I'll bet there are some installations that exceed this.
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"Yesterday's Dreams"1995 Carver 325 Aft Cabin 
Posts are amateur opinion only. You assume all responsibility for any action you take as a result of reading my posts.