I had the same engine on my 49. Tried to overhaul it, but as I took it apart, everything was knackered.
I ended up replacing it with a Beta 50, which turned out to be a really good move. Although it looks less powerful (50hp vs 78hp), it's actually more powerful, as it produces its 50hp at 2800rpm, so at cruising revs of 1900rpm, it's got more go, and at low revs (when manouvering), it has more torque as it's a 2.2l engine rather than the 2.0l of the VP.
It turns the other way, so you would have to replace the prop too, but I took the opportunity to fit a Featherstream, which again made a big improvement.
The Beta 50 pretty-much sits straight onto the same mounts as the VP, so is an easy swap-out, the rear mounts go through the same bolt holes, but the front mounts are about an inch further forward, so you just have to drill and tap some new holes. Exhaust is easy, but you will need a reducer to get down to the 2" diameter on the Beta.
If you have any questions about this you want to ask, please PM me. I can also upload some photos if you want.