oil/fluid change

I am planning on doing my own 100 hours service. Boat is a 08 Sanger V215 with black scorpion 330 motor. I am planning on changing the motor oil and v-drive fluid. The manual calls for Quicksilver 25w40 oil, which I plan to use. I checked for royal purple, which I hear good things about, but I could not find 25w40. Does anyone have any other suggestions? Also, I am going to use 30w for the v-drive. Is there anything else they do for the annual/100 hr service? Any tricks I need to know about? Also, when do you guys change your transmission fluid and what fluid should I use? Tranny is a velvet drive. Thanks for the help guys I tried a search, but did not find what I was looking for.

The Velvet Drive transmission uses regular ATF. You can use synthetic ATF but it really doesn't matter.
Any 25W40 oil is a heavy duty oil and could be used, it does not have to be Quicksilver. The important number is the number after the 'W' as that is the viscosity rating at operating temps. I use 10W40 or 5W 40 pure synthetic oil in the engine. That is one often labelled as 'European' engine oil. They are generally not rated specifically as a marine oil but most would exceed the requirements if they bothered to rate them. For me it's usually Mobil 1, or Castrol depending on availability. Royal Purple does a lot of marketing toward the marine industry but I have no direct knowledge. Generally, though, major brand synthetics work better than small marketers products. No problem using semi-synthetic or regular. I just like the properties of pure synthetics for a variety of reasons.
You could use a synthetic in the v-drive but, again, that is a choice.
At 100 hours also change the fuel filter/separator and lube the cables. It's also a good opportunity to check the belt and any bracket and mount bolts.

I too use 10W40 synthetic typically Mobil 1 but I switched to Motorcraft because I realized I can get it at cost here at work, no other reason. I use Mobil 1 synthetic ATF there again I'll probably switch to Motocraft on that too. I used Royal Purple one time but its a waste of money since I change the oil so frequently, this is the same argument many on here make for not using synthetic's period.

sounds good. Do you guys change your tranny fluid every 100 hrs?

Yeah. Oil every 50, tranny every 100, Vdrive first 100 then 300 there after.

I just finished the service on my Nautique. I would highly recommend using an extractor pump to change all the fluids and run the boat to operating temps before the change.

I could only remove a little over 1/2 of my trans fluid and was told this is normal. Just make sure you put the same amount or slightly less fluid back in.

Changing the v-drive oil change maybe overkill unless your boat has a lot of hours. My Walters manual says to change it every 500 hours and some say it can last longer.

I would recommend changing or checking the impeller when you do the fluids. Some people do it every year. I feel every two years is sufficient. I had one go out on me and it was not fun.