Mercury 4 Stroke Oil Drain Valve

Did a service on the '17 Mercury 150 on Saturday. Found the oil drain valve to be seized with plenty of salt build up.

I opened it up with a breaker bar but found one of the three o'ring had picked up/was damaged. Being Saturday afternoon that put a holt to Sunday fishing plans with the young fella...

None of the major mercury dealers carry the o'rings in WA. After a little bit of googling i found a US website the cross matched the Mercury part number with the actual o'ring size in the description #winning.

Quick trip down to Hallite and i now have a full set of o'ring/seals for the oil drain valve.

Problem is $10minimum and only $2 worth of items... So if any FW members with a new merc who do their own servicing suffer the same fate, I’ve got 4 spare sets of seals kicking around my garage.

ranmar850's picture

Posts: 2448

Date Joined: 12/08/12

Couldn't fit from a kit?

Mon, 2020-01-20 15:42

 I have a couple of o'ring  kits from Hare and Forbes, cheap and seem to cover most emergencies, seeing as I am sorta remote. 

NORUN NOFUN's picture

Posts: 557

Date Joined: 15/08/11

Did an o-ring on the oil pump

Fri, 2020-01-24 09:44

Did an o-ring on the oil pump on my outboard, Evinrude didnt make the part and only supplied new pumps (fu*n piece of shit etec's), stripped it down, removed o-ring, whipped over to a seal place in Wangarra, they measured up and made me one for free using oil resistant material.
Wish I could remember their name but there are certainly alternatives out there to get you going again.

gruntre69's picture

Posts: 527

Date Joined: 15/10/16

 Yes mine was close to seized

Mon, 2020-02-03 15:58

 Yes mine was close to seized the first time I did mine too. Removed it completely and used anitseize to re-assemble.  I actually have a silicon rubber cap over mine now to keep the salt out.

Keep a close eye on corrosion around the thermostat housing too mine was starting to corrode there too, I take it off every service now to inspect..

I'm less than impressed with Mercury parts service, I'm now waiting 6 weeks for engine mount blots which sheared off....


 Marine trimmer NOR (available for clears, tops, carpet, upholstery, custom equipment covers)

Darren253's picture

Posts: 437

Date Joined: 23/07/16

I pulled the thermostat

Mon, 2020-02-03 18:10

I pulled the thermostat too.

Spotless inside but a fair amount of salt buildup around the seal face.

Gave it a good cleanup and reassembled with a liberal dose of marine grease. 

Most of my genuine parts will be coming from the net 

Darren253's picture

Posts: 437

Date Joined: 23/07/16

I pulled the thermostat

Mon, 2020-02-03 18:11


Posts: 534

Date Joined: 21/05/12

 thats why suzis and yammis

Mon, 2020-02-03 18:31

 thats why suzis and yammis cost a bit more

bought parts from them before got it in less than 5 days -cost me half off Australian price -after shipping

they also show all the schematics if uwanna pull something apart

mercury tho has sown it up -they wont sell Mercury parts outside US

u can use a shipping forwarding service

or PM me for a bloke that will post it on - gonna set u back a  6 pack  tho ;P 



crano's picture

Posts: 542

Date Joined: 04/11/09

Anti seize

Mon, 2020-02-03 19:10

 An outboard mechanic  told me a long time ago never to use anti seize on an outboard as it contains metal that reacts with aluminium.