Gear Oil Drain Plug Gasket

Grazer · Posted: Mon Oct 20, 2014 3:30 pm Post subject: Gear Oil Drain Plug Gasket

Hello All,

Putting the boats away for the winter is always a sad time of year, but sadder is trying to locate those gaskets for the plugs on the gear oil drain screw. As we all know, this critical component, must be replaced every time the screws (at least 2 per motor) are removed. Does anyone have a good source on where to purchase a good crush washer to fit all makes of my outboards (Honda, Tohatsu)? It seems to me the size of the drain screws are fairly similar on both engines (in terms of diameter and mating surface between the lower unit and screw).

Thanks,
Grazer

srbaum · Posted: Mon Oct 20, 2014 5:56 pm Post subject:

Grazer,
I order my lower unit screw gaskets and all other outboard parts from boats.net or partspak.com... easy to do from your best recliner.

journey on · Posted: Mon Oct 20, 2014 6:39 pm Post subject:

Actually, I use those o-rings a couple of times. Haven't been caught out yet. Just look at them and see that they haven't been torn.

Is that cheating? They're expensive little buggers.

Hmm, I just lied, for a Honda they're either $0.63 or $1.32 @ boats.net. Just wait until you have some other parts to order (such as fuel filters,) and get 1/2 dozen of them. It's the shipping that makes them expensive. And don't put them somewhere that you'll forget about.

While I'm on the soapbox, remember that Honda anodes aren't necessarily zinc. They could (and should) be aluminum or magnesium. I called Honda customer service to see of what they're made, and they couldn't tell me. I do know the Honda ones are lighter than the non-Honda zinc ones. So I'll buy the Honda ones. I figure Honda knows what Honda needs.

Boris

shellndanm · Posted: Mon Oct 20, 2014 7:57 pm Post subject: gasket

Anyone have the part number for the gear oil gasket on a honda 90? Couldn't seem to find online. Thanks

journey on · Posted: Mon Oct 20, 2014 8:51 pm Post subject:

Try this link: Honda 90 Lower Gear Case. Hope it's the right 90.

I think it's #40 or #53 in the diagram. Note that 40 is a plastic washer, 53 an o-ring.

Boris

BrentB · Posted: Mon Oct 20, 2014 9:01 pm Post subject:

I have a Yamaha OB and bought a bunch several yrs ago when ordering other parts. eBay has a bunch of crushable washers listed but I use onlt factory items

Grazer · Posted: Mon Oct 20, 2014 11:26 pm Post subject:

Thanks for all your comments. I have looked at boats.net and yes the shipping is the expensive part, especially outside of the USA. I haven't checked out partspak.com yet. Any other on-line sites folks are using that have had success with for ordering engine parts would be greatly appreciated.

Grazer

BrentB · Posted: Tue Oct 21, 2014 6:32 am Post subject:

I ordered Yamaha parts from SIM Yamaha

Rcbeach · Posted: Tue Oct 21, 2014 9:32 am Post subject:

In 2004 or 2005 Honda made some design changes to their gear cases. Since that time I know for the 50 and 90 HP models an "O" ring is used not the plastic washer. Boat.net will give you the correct part and number.

srbaum · Posted: Tue Oct 21, 2014 9:47 am Post subject:

Grazer,
I have a 90 HP Honda 2002 on my 2001 C-Dory and a 90 HP Honda 2005 on my rigid hull inflatable. Both outboards use the old style nylon washer (Honda part number 90507-921-000 WASHER, NYLON ) on both oil drain and vent screws on the lower units.

BrentB · Posted: Tue Oct 21, 2014 9:49 am Post subject:

I bought boating items from BOE Marine and they also sell Honda parts in case you are shopping around. Jim at BOE provides excellent support just like Andy at SIM. Both businesses have forums on The Hull Truth as a fyi

TABMAN at Bennett Tabs is the gold standard on customer support. He is worth his weight in gold ten fold.

Rcbeach · Posted: Tue Oct 21, 2014 1:32 pm Post subject:

Steve,

My mistake, on the 90 HP the change was made to an "o" ring in 2007. I checked with boat.net and nylon washers were used up thru 2006.

Dick

rjmcnabb · Posted: Tue Oct 21, 2014 3:25 pm Post subject:

Hi Rcbeach,
Can you, or anyone else, tell me if the newer O-rings are a suitable replacement for the nylon washers? I never thought of a nylon one as being a "crush washer." "Crush washer" is what I think of as used on a spark plug, a kind of complicated toroid shape that squashes down when you torque the plug. Question

Rod

Rcbeach · Posted: Tue Oct 21, 2014 6:32 pm Post subject:

Rod,

The gear case that uses an "O" ring has a bevel where the fill/drain and check plugs are inserted to squeeze the "O" ring between the plug and the case making a tight seal and also allowing the plug to contact the case metal to metal to make for a secure fit. I assume that the gear case that is designed to use the nylon washer is flat. If an "O" ring is used on this configuration, the "O" ring may be destroyed if over tighten, allowing leakage. I do not have any experience with the older Honda models designed for nylon washers, maybe someone else can provide that information. I do know that the local mechanics where I live use the nylon washers on gear cases designed for "O" rings apparently without problems. I don't recommend doing that.

Dick

rjmcnabb · Posted: Tue Oct 21, 2014 8:27 pm Post subject:

Thanks, Dick. My OB is a 2005, I think, so I guess P/O probably did not substitute nylon for O-ring. I'll be very careful when I pull Luna for the winter. Cheers, Rod