Suzuki DF90-115-140 exhaust issue
I love the Suzis on my boat, reliable smooth quiet despite pushing up to 600hrs. Ive serviced them religeously and checked compresssions etc.
But a couple of months ago while googling some service info for my pair of DF115's, I was pretty suprised to come across this
http://www.thehulltruth.com/boating-forum/395845-suzuki-df140-engine-holder-corrosion-fix.html
and ALOT of other similar threads from both US and Aus. I hadnt heard about this before and was pretty suprised, but given the sort of use my boat gets (remote long trips with the kids etc) and being an engineer I decided to bit the bullet and have a look.
NOTE-the pics below that have a corrosion hole were borrowed off another website-the repair ones are mine.
Mine had plenty of meat there in both engines
Basically Suzuki designed the DF90/115/140 to have an O2 sensor fitted in the exhaust/engine holder casting but must have decided at the time it wasnt required. The hole was removed completely from these outboards around 2007 so is only an issue up to that date.
Interestingly the new "Lean Burn" Suzukis, is really just the addition of an O2 sensor (experts correct if Im wrong!)
One of the rare less smart Japs at the factory then decided to use up the seacontainer load of mild steel plugs to fill the hole.
The combination of hot exhaust gases, salt water and galvanic reaction then proceeds to corrode away the engine holder until it blows thru and burns the wiring loom which runs past that point. This brings up a 3:2 alarm code
I believe a faulty thermostat (causing cold combustion) increases the acidity of the exhaust gases also.
Anyhow, I found a mob in the US who makes aluminium plugs specifically to replace these and at about $15 each plus $10 post they were on my doorstep in 10 days.
I also ordered magnetic drain plugs for the gearboxes (should be standard in any machinery).
Couple of days back my flights to work were delayed for a day so I thought f++k it, lets do it.
Stb engine first, covers off, 8mm allen key socket-FK, no go. Loaded it til hex was buggered.
Opened port covers, same thing, but it came loose when forced to the limit. With some trepidation I looked in and was glad to see plenty of meat there.
Fitted the Goldplug then went back to the stb.
Out with the welder, and welded a bolt onto the plug.
It took a fair bit of force (18" bar) but came loose, quick internal inspection (phew all good in there) and fit the Goldplug
If the hole blows thru, a new engine holder is about $US1K plus about 6 hrs installation or it is possible to weld up the hole as quite a few have done but Im happy to have caught mine early sorted it.
When I get home in a month I'll have to take it for a test run to the islands 
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
fishy fingers
Posts: 1719
Date Joined: 28/04/07
i take it these pics are not yours or are they
I have read the same Rob but I also read somewhere that the problem was with earlier models (mine is 2012) and suzuki had addresse the problem
whoops just commited the cardinal sin and not read the post properly...I see they are yours!!
Deleted
Posts: 6265
Date Joined: 26/04/14
hope so iam about to lash
hope so iam about to lash out some coin on a 90
Rob H
Posts: 5796
Date Joined: 18/01/12
problem was fixed (no hole
problem was fixed (no hole there after 07) so no more issue.
Ive had a Yam F115 and these DF115's and they are both great motors-top engineering hence why I was so suprised to find such a stupid mistake by them.
Sorry should have said, couple of the photos with the corrosion hole in were robbed off the Hull Truth
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
fishy fingers
Posts: 1719
Date Joined: 28/04/07
i thought so
!Iwas sure I had seen them before!
southcity104
Posts: 1659
Date Joined: 27/01/09
Gday Rob
Cheers for the heads up. A few months back I had a go at removing that plug. No love. Allen key to half inch socket then and extension to a strong bar. Might have to go your way with the welder.
"Its a life style job"
Rob H
Posts: 5796
Date Joined: 18/01/12
hey Tony, if you go with the
hey Tony, if you go with the welder, use a 1/2" bolt and 2mm rods. Pull the wiring loom/rubber seal well up out of the way.
But if you havent yet stripped the hex, start it up on the muffs so that area gets hot then use the allen key until it gives or hex strips (nothing to lose).
Worse case though is having to drill it out, very difficult to drill out a steel plug in aluminium
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
sea-kem
Posts: 14967
Date Joined: 30/11/09
Good heads up there Rob.
Good heads up there Rob. Mine's a 2006 DF90 so in that range. Looks like another job to the list.
Love the West!
Rob H
Posts: 5796
Date Joined: 18/01/12
I probably should have jumped
I probably should have jumped on here to see if others wanted to get a package of the plugs, but thought Id buy them then have a look and flog them if ok-but then I just fitted them anyhow
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
wangler
Posts: 607
Date Joined: 26/04/08
Tried to get mine out about
a year ago with the 8mm allen key, but could not budge it. Might wait for Tony to have a go at his motor 1st before I try again
Want to make someone mad... tell a lie! Want to get the world upset... tell the TRUTH !
Dougie
Paul_86
Posts: 1449
Date Joined: 27/03/09
Question. I've got a 2006
Question. I've got a 2006 DF70, which I have heard is the same as the DF90, just the 90 has a different computer/tricked up a little. Anyone know if that's true? If so then I better look into the problem as well.
cheers Paul
sea-kem
Posts: 14967
Date Joined: 30/11/09
Yep virtually same motor and
Yep virtually same motor and weight Paul. I researched this for my project boat. Def worth looking into.
Love the West!
Rob H
Posts: 5796
Date Joined: 18/01/12
not as far as I know-the
not as far as I know-the 90-140 are I believe a separate family of engines as Ive never heard the 70 mentioned in the issue.
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
Paul_86
Posts: 1449
Date Joined: 27/03/09
Yeah pretty interesting,
Yeah pretty interesting, everything I've read previously has said they are the same engine, but just got a bit "hands on" in the garage and it looked nothing like the photos. Maybe I've got the engine year wrong. It had the bottom plug you can see, but located lower down, and the top plug wasn't there at all, so thinking it must be a newer model.
Rob H
Posts: 5796
Date Joined: 18/01/12
the bottom plug is the
the bottom plug is the flushing port and doesnt go into the exhaust, I think the guy who edited the pic got that part wrong (borrowed off Hulltruth).
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
big john
Posts: 8749
Date Joined: 20/07/06
Nice
Nice work Rob.
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Rig
Posts: 2925
Date Joined: 27/12/06
Gold plug
Just had a look at mine, I have one but no corrosion and it looks like that plug on the rhs is steel too. Not sure what that one is for but if has been opened before and there is a little big of surface rust on it where someone has used an Allen key
crasny1
Posts: 7003
Date Joined: 16/10/08
No engineer Rob
But can you elaborate what that would do if there was a hole in the plug area like the top photo. I have a ETEC so not an issue for me, but the old man has Susie 115's on his boat in that vintage. Ill forward this to him with interest.
"I would like to die on Mars. Just not on impact!!" _ Elon Musk
Rob H
Posts: 5796
Date Joined: 18/01/12
hey Cras, Im out at sea just
hey Cras, Im out at sea just now with a super slow internet, but if you jump onto the Hull Truth, quite a few guys have welded a plug in there.
Alternative is to buy the engine holder and fit ($1Kus plus about 6 hrs labour)
When I get better cover, I'll chuck up a link.
Remember its only a problem pre-07 or so.
The pictures above of the holy ones were "borrowed" off THT
EDIT-just read your question better
What it does is, first up starts to fill the under cowl area with exhaust fumes which trigger poor running and an engine warning (3-2 from memory) for MAP or MAF sensor (manifold air flow/pressure)
Right next to that area is the engine wiring loom which burns thru after continued running. I believe if it happens at sea you can just remove the cowl to get home if the wiring is intact.
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.
fshnNoob
Posts: 1
Date Joined: 12/02/21
what about the other bolt?
What about the other bolt; the one immediatly above "Check these two areas" Will this one suffer the same issue??
My motor is a recent purchase, after reading this thread I checked my motor to find the "problem" bolt has been removed and a substantial plate welded as a cover. All Good :-) But, I then noticed another bolt, very close to the problem bolt. Will this bolt be an issue as well ??
Rob H
Posts: 5796
Date Joined: 18/01/12
Which one? Bolt or plug?Its
Which one? Bolt or plug?
Its the plug that corrodes thru as its a mix of acidic exhaust gas, heat and salt water
Give a man a mask, and he'll show you his true face...
The older you get the more you realize that no one has a f++king clue what they're doing.
Everyone's just winging it.