F225 gearcase plug and washer

[fairdeal]

doing a 100-hour service today,
I'm not liking the lack of translucency in the drained gear lube.

Not "milky" - not as bad as when my shaft seal garter spring went -

but some degree of "opacity"

Now, I've always been a bit of a skeptic about the criticality of the fiber washers

but scrutinizing them, the top plug and washer look perfect - I would put that right back in

interesting aspects to the drain plug - the washer is a bit oval-ated - and chewed up

but what is strange is the sizeable burr on the sealing surface of the plug -
appears to have just been made that way - with a crude finish

I'm going to refinish that surface - and of coarse the gasket is shot

but I am still skeptical that water could have entered there.
Going to do a pressure test..

[boscoe99]

His name is Aaron.

[99yam40]

I never noticed any imperfection on the sealing surface of the plugs before. maybe I need to look closer from now on.

I have reused them before, but Yamaha recommends new each time.

I have noticed after installing new that they need to be re-tightened after a little time.
usually see a small bit of lube leak out and the plug screws in a little more

[robert graham]

I'd replace that drain screw with the burr on the sealing surface...that can't be real good for the sealing. New drain screw is about $7.00 last time I checked....

[panasonic]

I wish they would make the plugs with a hex recess for an Allen key and not the bloody slot that you can never find a flat head screwdriver that fits it properly...

[DennisG01]

That's odd - I've never seen a burr like before, either. But maybe I've just missed it? It kinda looks like it's "supposed" to be there, but I don't understand how it can be a good thing. I suppose one could say it helps to "lock" the plug in place?

I can see how that would cause the gasket to become oblong though. As the plug is tightened down it would start putting an outward pressure (sort of squeezing the gasket outward) on the gasket. You can even see the effects of it there in your picture.

Screwdriver... Get a screwdriver adapter for a socket wrench. They're available in large sizes and make it MUCH easier. If one is slightly too big, just grind it down. I keep one on a stubby wrench. If you need extra help removing the plug then a impact screw tool (hit it with a hammer) works well. But you usually only need that impact tool if it was "someone else" that originally tightened the plug and went way too tight.

For what it's worth, I always replace the gaskets. For the couple bucks it costs, once a season... as opposed to a WHOLE lot more for a new gearcase... I consider it as good insurance.

[pstephens46]

Maybe that burr is to bite the gasket and lock the screw in place?
New gaskets definitely like to loosen after first couple runs.

Please post results of pressure test. I used the hack method or replacing my prop shaft seals also....

[fairdeal]

well - the needle never moved for >20 minutes



So - maybe the washer was leaking. I got my money's worth from it -
3 years, 1000 hours, its been on and off almost a dozen times...

I put the drain plug in the drill press and filed that nub off -
then a final polish down to 400 grit
looks nicer than the vent plug now

I used the old vent plug washer for the pressure test fitting - so that still holds.

But I've been sitting on two brand new washers for some time now-
so I'll go with new washers on both plugs

[99yam40]

like said before check them after a little time seems the new ones crush some and need to be tightened up a little after a run or 2

[robert graham]

I wish they would make the plugs with a hex recess for an Allen key and not the bloody slot that you can never find a flat head screwdriver that fits it properly...

I've seen some catalog aftermarket drain/fill screws for Yamahas with the hex/Allen heads....seems like the hex/Allen would be better and easier to work with....I got a big gorilla screwdriver and filed the tip to fit that slot snugly and it works fine so far....

[TownsendsFJR1300]

like said before check them after a little time seems the new ones crush some and need to be tightened up a little after a run or 2

Plus 1 ^^.. I always replace the washers, it's just not worth the potential of water entry.

Of course there shouldn't be any irregularity there and it definitely ate up that gasket which probably is (also with your testing) why the funky oil..

The "bits" for the hand-held impact tool usually have a large bit that fits perfect in there. Between that bit and the impact tool, it's pretty easy to get a good grab on that bolt.

And "second" re-tightening after new washers, I've always found they needed just a slight tightening..


Wouldn't mind Allan head bolts with the correct size and magnetic for the bottom plug! Great idea..


Also, for anyone needing a threaded nipple for the pressure test, you can use the "end" (and hose) of the pump style LU oil pump (quart).

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[panasonic]

I just got a hate on for all slotted screws...always have. Up here in Canuckastan we don't use them very much....we got robertson head screws, much better.

I have replaced all the engine case bolts on several motorcycles with Allen head bolts ( got rid of the phillips) and no more impact driver is required....again much better.

[panasonic]

I've seen some catalog aftermarket drain/fill screws for Yamahas with the hex/Allen heads....seems like the hex/Allen would be better and easier to work with....I got a big gorilla screwdriver and filed the tip to fit that slot snugly and it works fine so far....

Alright if its you own engine...it is when you work on somebody else's engine and the slots are already torn up from wrong screwdriver and being over tightened.

I'd lock wire them if I could....never did like the no self locking on those plugs.

I wonder how often and how many loosen up and fall out..?

[99yam40]

Alright if its you own engine...it is when you work on somebody else's engine and the slots are already torn up from wrong screwdriver and being over tightened.

I'd lock wire them if I could....never did like the no self locking on those plugs.

I wonder how often and how many loosen up and fall out..?

only one I ever heard about was a friends that he drained but never filled back up, was going to buy some new oil next time into town. he forgot and was asking why it came out.
he just did a test run for a few minutes and parked it back in drive way.
he bought a new plug, flushed it out well and then filled up, no problems with that motor. but the other one came apart because it did not have any oil in it on a off shore trip. he had drained that one also at the same time as the other on and did not fill it either, that plug did not fall out.

[TownsendsFJR1300]

Alright if its you own engine...it is when you work on somebody else's engine and the slots are already torn up from wrong screwdriver and being over tightened.

I'd lock wire them if I could....never did like the no self locking on those plugs.

I wonder how often and how many loosen up and fall out..?

You could always use some light to med duty loctite. Something not crazy hard to remove every year..

That or just a touch of Yamabond (case sealer) on the threads. Seals and bonds..


With that said, I've never lost one..


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