Plastic (and now broken) Yamaha outboard oil drain plug

mikeywil

mikeywil

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Help please for a non-mechanic!

My simple plan was to change the oil on my late 90's Yahama 9.9 outboard. To remove the oil I attempted to unscrew the oil drain plug and the head snapped off leaving the thread part in the casing. I now have managed to remove the thread part too, but I can't find a replacement anywhere. Yamaha official dealer says there are none around including in Japan... I have placed an order with CMS in the Netherlands, but nothing seems to be happening there and I suspect they don't actually have one.

The plug is/was plastic with a brass bolt head. This is what it looks like:
plugdrain_medium6G81347100-01_e4ca.jpg

I think the solution is to just buy a replacement that isn't specifically designed for the engine, but one that has the same thread. So, I was thinking of an M16 x 1.5 like this one from Amazon:
51RY-FpM5TL._AC_SX425_.jpg


Is there anything I should watch out for - such as the fact this is not plastic/nylon!?
 
I'd be a bit wary of mixing titanium with aluminium. There's a big difference in their galvanic potentials. Ti might be a worse choice than stainless steel.

Any friends in USA ?
Boats.net have just 1 in stock.

Tried a Yamaha motor cycle dealer?

Know anybody with a small lathe who could make you one (or three) ?
 
Off topic, but the spec for the 90's 9.9 Yamaha is identical to the 15, except for the two jets, which are cheap as chips and easy to replace.

I understand the reason for this is that in the land of the free, you need some sort of licence to drive a boat with more than a 10hp engine, so Yamaha jimmied the jets to decrease the HP rating
 
Thanks for all suggestions so far. Replacing with something in stainless steel seems a popular suggestion, but as @DownWest says...

DownWest said:
Out of interest, I wonder about the plastic body and brass head. Seems quite fancy for a simple drain plug?
Click to expand...

... I was thinking the same. Perhaps the ideas was that it can tighten into the casing without risking stripping the thread?

Maybe I need to find someone with a 3D printer!
 
mikeywil said:
Thanks for all suggestions so far. Replacing with something in stainless steel seems a popular suggestion, but as @DownWest says...



... I was thinking the same. Perhaps the ideas was that it can tighten into the casing without risking stripping the thread?

Maybe I need to find someone with a 3D printer!
Click to expand...
Just curious.. is this a 4T or 2T? and, is it the plug for the engine, if 4T? or the gearbox at the prop?
My ones are 2T and the plug is down the bottom. All ss.
 
DownWest said:
Just curious.. is this a 4T or 2T? and, is it the plug for the engine, if 4T? or the gearbox at the prop?
My ones are 2T and the plug is down the bottom. All ss.
Click to expand...
This is a gearbox drain screw

1653589894822.png

Good point about them being stainless steel
 
SpiderMoobs said:
Off topic, but the spec for the 90's 9.9 Yamaha is identical to the 15, except for the two jets, which are cheap as chips and easy to replace.

I understand the reason for this is that in the land of the free, you need some sort of licence to drive a boat with more than a 10hp engine, so Yamaha jimmied the jets to decrease the HP rating
Click to expand...
That sounds interesting!!! I could do with some extra ooomph
 
On the very (off topic!) topic of Pro Furl parts - check out this affront to reason and economics:
97696-ABF-63-DA-4-DFA-A084-4-AC77-EF477-B7.jpg

(16mm clevis pin - threaded M12 both ends with standard nylocs)

The price sticker isn’t evidence of a greedy swindlery either - the boatyard just use them as a way to record cost plus carriage and VAT for when punters come to pay up.

There were sharp intakes of breath and choice words from the boatyard staff as well as from me!
 
Might this do it?
1653595937930.png

On the other hand the drain plugs on aluminium outdrives and on my outboard are stainless steel and nothing bad happens.
 
To the OP
Where are you based?
If you are really stuck
If I had the outboard to hand I could turn up & cut a thread on a piece of plastic I assume it is for gearbox so not very hot.
I would want to fit rather than just make it & post it. Need to check thread pitch etc
 
Daydream believer said:
To the OP
Where are you based?
If you are really stuck
If I had the outboard to hand I could turn up & cut a thread on a piece of plastic I assume it is for gearbox so not very hot.
I would want to fit rather than just make it & post it. Need to check thread pitch etc
Click to expand...
A very kind offer!

It's not the gearbox - it is the oil sump for the engine, so will be somewhat hot I'd have thought (I am no way a mechanic). I'm on the north Kent coast just out of Faversham.
 
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