Merc Outboard 9.8 milky discharge from prop

[opalized1]

Had my Merc Outboard 9.8 on the water for only the second time this weekend, trolled around for 10 hours without a hitch, motor ran amazingly well, from start up to shut down, never a stumble.
towed the boat home and went out this morning to a saucer size puddle right below prop on the street of a milky oil substance staring up at me, attached a pic of the prop. (wont let me attached, a reduced size image) so to explain, the milky oil like substance is a creamy white in color and thick like oil
I haven't had a chance to pull the plug on the lower unit yet, but kinda confused, what could be the possible causes of this discharge from the prop area??

 

[Scott Danforth]

Check your lower unit oil if its low, you probably have the shift shaft seal going, if its fine and no water in there, then it would be unburned fuel and oil from the exhaust cavity.

only two locations it can come from

 

[Sea Rider]

OP has not specified it it's a 2 or 4 strokes OB, if we assume it's a 2 strokes. Usually white creamy equals a bad lower leg prop seal. Black, smelly and gummy equals unbruned fuel/oil lefttovers draining from combustion chamber down exhaust chamber and through middle prop, very notorious on 2 strokes OB's.

Drain lower leg oil remains, add new oil, use it some hours, check if milky, if so, buy a lower leg seal kit and replace old one.

Happy Boating

 

[opalized1]

its pretty white and gross, ill pull the fill and drain plug on lower unit and see what ooozzes out.
all my ole paper weights are 2 stroke.
Thanks Guys nice having back up when dealing with these diansaurs

 

[opalized1]

Well pulled the plug on lower unit (drain, and clean pretty blue oil dribbled out, appears brand new, so how else would water impregnated water get into exhaust, when visibly there are no signs coming from the motor it trolled like a dream for 10 hours, and then when I pulled the fuel line at the end of the day to run the carb out of fuel, it ran like a banshee at 2/3 throttle till the carb ran out of fuel

 

[Watermann]

Sounds like the LU is good then if there's no milk inside the gear case.

Pre-mix build up with carbon in the exhaust housing after 10 hours of trolling maybe? What ratio are you mixing at? Old enough to be 24:1?

I would run it on muffs until warm and do a decarb hot soak on the motor with Seafoam or power tune. Next time out run some Seafoam in the fuel and run it at WOT for a while to clear out some carbon.

 

[racerone]

Not many of the 9.8 models were to be run on 24:1 -----50:1 it was for Mercury.

 

[Scott Danforth]

Its a 9.8, last ones built in 1985. all 9.8's were 2-stroke and nearly all ran on 50:1 after the 9.8 was the larger displacement 9.9.

Since the outdrive oil didnt have water in it, it is most likely unburned fuel and oil

 

[Sea Rider]

Yep too much oil mix in fuel or too much run hours at trolling speed or a combo of both which 2 strokes OB's dislikes. Go as per Scott's advice.

Happy Boating

 

[opalized1]

Great advise guys im praying, since I first fired the engine, about 20 hours ago it has never been run at wide open, until we came dock side sunday last, at which point I disconnected the fuel line and ran at 3/4 throttle till it died. So next time out, ill go ahead and use it to get us to our fishing hole, once warm running it wot for prob half hour to see if that cleans it out.
Lord knows prior to my ownership, this motor had probably sat for many years, I had to completely rewire the coils and such, all wiring was replaced, everything was rotten. So a good running will probably work miracles. Although it has run like a dreams since I started using it 3 days now ive trolled half to all day, saving my wallet, and my 115 which had been my trolling motor prior.

 

[Scott Danforth]

3/4 throttle in neutral? good way to have the pistons come out the side of the block

 

[opalized1]

no 3/4 throttle in forward, under load skooooting the big ole pig 18 ft aluminum boat along at a nice clip actually, first time I had ever run it up off idle since putting on the boat, was kinda fun

 

[Sea Rider]

Take advantage to run carb dry while OB is flushed with fresh water on muffs. Geared at fast idle will suffice. Just watch for prop it's spinning..

Happy Boating

 

[opalized1]

Gluttin for punishment, just picked up another, 9.8, mine is 1973, this one is 1971, $100 bucks, seems in pretty darn good shape for the age, im gonna hang it tonight and pump some fuel in it and see what happens, the throttle linkage on this one is far better shape than my original, the grease was so dry it wouldn't hardly run cold until I cleaned most the old grease of and added alittle new, and someone had tried to turn the throttle past the start position with it in neutral and damaged the assy, so getting the idle and off idle is alittle troublesome,
But it runs like a dream so cant complain

 

[Chinewalker]

Oily discharge is completely normal. 2-strokes are dirty motors. Troll them all day and they're even dirtier. Can be worse if the motor is out of tune - a miss-fire, dirty carb, misadjusted carb float, low compression, etc. can all exacerbate the issue.

 

[opalized1]

This motor, other than alittle stubborn starting, in 20 degree weather, idles perfect at a very low hum (approx. 500 to 600 rpm by my ear) accelerates great, humms along at 3/4 throttle without a hitch, I have done nothing but rewire the coil to points wiring, it has an old old impeller in it, lords truly knows how old, and pees instantly and solid all day, shifts perfect, so would seem Chinewalker that everything is singing pretty close to true, and having sat im sure it was alittle gunked up inside and having only run it about 20 hours now its just cleaning itself out, should clear up with alittle more run time, my 1150 merc same general year of manufacture, idles 12 hours a day trolling prior to getting the 9.8 running, and after about 100 hours of that, without doing a thing to it but hooking up the wire loom and a fuel line, again a motor that had sat for many years im sure, ran like a top till the most recent 12 hour trolling outing, at which point it began fouling the plugs every couple hours, 10 minutes of a reasonably high idle in neutral cleared it right out and it would troll along again without a hiccup for another hour or so, gonna guess these plugs are quite old so may be time to replace them, and the distributor cap may be starting to carbon track as well, which I don't believe running off idle for a bit would cure so easily.
Both motors combined only cost me $320 bucks, so the time ive already run them seems a pretty good deal for the money, and both still run excellent in there current state, assuredly alittle upkeep would only make matters better, plugs wires etc.

 

[opalized1]

SEA RIDER, not sure how muffs would work on 9.8 has intake right above prop horizontal to ground, I use a 35 gallon pickle bucket for this motor when required

 

[Sea Rider]

SEA RIDER, not sure how muffs would work on 9.8 has intake right above prop horizontal to ground, I use a 35 gallon pickle bucket for this motor when required

So this model doesn't have the traditional double water screens side of lower leg, but has a water screen right under middle AV plate and parallel to prop shaft, right ? There are special muffs for this kind of lower leg screen, but will need to remove prop every time it's used so to hook muffs onto lower screen which is cracy.

If using a barrel, install a faucet on lower barrel for heated and oily water to exit barrel while a hose fills fresh water into upper barrel. That way won't flush and cool OB with heated recirculating water.

Happy Boating

 

[QBhoy]

Surely it’s just 2 stroke oil mixing with water. Usually noticeable when over oiled and in the trunk of your car !

 

[JimS123]

"Newer" 2 strokes are loop charged, which means that the products of combustion recycle back thru the engine. The Oldies had the gunk from the exhaust (including all the oil in the tank) discharge out the bottom thru the cooling water passages.

My newer engines run clean. The oldies drip oily wet discharge for days. If you trolled for hours the gunk coming out the bottom will be even worse.

Sounds like you don't have a problem. Just put an aluminum pan under the motor and it'll collect the gunk and keep the garage floor clean.