Lower unit oil for a 225 - fully synthetic or doesn't matter?

Hi guys,
I'm just about to change the oil in the lower unit of our '06 BF225. The lower unit was brand new last year [after the old one lunched itself] and has done about 25 hours since being fitted - other than GL 4/5 and SAE90 is there anything else I should be looking for (i.e. fully synthetic)?

Also, should I be doing this with a pump and if so is will the generic ones fit the drain hole thread or is the Honda fitting different?

Use what oil the service manual calls for the honda guys will tell you if the drian plug is a standard thread. Your local honda dealer will have what you need. Be sure and change the washers regularly also.

http://www.ebay.com/itm/Honda-08200...ash=item25a1fb5187:g:JbwAAOSw34FVDIkc&vxp=mtr
looks like it has a metric thread

Mercs High Performance gear oil is what I use in a Honda. I service a local Yacht club with Honda and Yamaha power. Haven't lost a lower since I have been using High Perf Merc Gear oil. These boats get tortured.

Merc High Perf Gear oil works in everything except Volvo SX and HD Yamaha lowers.

Thanks Chris, that's the sort of recommendation that makes this forum so excellent

To reinforce what Kim wrote - those rubber O rings on the drain plug and level check plug are really important. You probably don't need to change them this time with the unit so new. But next time for sure. My records show part number as: 91301-ZW4-003

Be sure to check the magnetic fill plug for metal fragments. Given a new unit, you will probably see some small ones because of break in. Big chunks indicate a possible serious problem. After this oil change, then you should only see tiny metal bits no bigger than finely ground coffee. Always clean off the magnetic plug before re-installing.

If possible, let the old oil drain out overnight. Once filled with new oil, let it sit for awhile to let air work its way to the top of the unit, then pump in more oil until it starts seeping out of the check-level plug. You can accelerate that process by reinstalling the top plug and raising/lowering unit several times.

Finally, it's real easy to bugger up the screw slot in the heads of the two plugs. I've found that the judicious use of an impact driver loosens them up very quickly and cleanly.

Great thanks ...... I'd already ordered the new O rings but will check the existing ones. I suspect that the old unit failed because one or both O rings weren't renewed by the company that did the engine service just a few hours before the failure

Hello, there is a great video regarding lower unit service on these engines. I put together one of the pumps he recommends and it really makes it easy. check it out, it's on youtube https://www.youtube.com/watch?v=hQurk7fjm7s , or you can search bf225 lower unit service on youtube to get to it. Cheers!

Also, put two quarts of Mercs High Performance gear oil in your pump. It takes a little over one quart to get overflow on my 225.

Yes I've used a couple of his videos for servicing and the gear oil change - very helpful indeed.

I do wonder whether the lower units have been made to take 1.1L of oil so they can sell more oil!

No wonder the oil companys have so much $$$