Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Moody Blue · Jun 2, 2005

First time out this year with this motor. Started fine and trolled with it for about 2 hrs then it started to run rough then quit. Hard to restart but got it going then there was a qty of white oily sludge ejected from the exhaust. This happened several times over the next couple hours. After trailering the boat we noticed the inside of the prop (exhaust) was coated by the same oily sludge. Any thoughts what this is and what is causing it ?

REELSPORT · Jun 2, 2005

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Might be you need to do a decarb on the motor carbon will form on the inside of your engine and should be decarbed about every 50 hrs if you are not running a decarb product thru your gas. Do a search on decarbing engines at this site and you will get some helpful information. good luck

Xcusme · Jun 2, 2005

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Rod, You're looking at the results of a lot of slow trolling. It's a combination of exhaust by-products and unburned oil. If you go WOT for a bit, the exhaust will expel the accumulation.

moderator1 · Jun 2, 2005

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

You may also want to gap your plugs at about .040 if you have them at .030.

Moody Blue · Jun 8, 2005

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Thanks for the info. Sorry about getting back so late but things have been hectic. Yes this motor is run at trolling speeds about 80% of the time. Perhaps a good run up and down the lake a few times should clear it out. Think I'll do a decarb first then go fog the mosquitoes

dajohnson53 · Jun 8, 2005

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

What I tend to do if I think of it is run the motor at WOT or at least at a midrange rpm cruise for a minute or so after trolling, before shutting down - if this is at all practical. In my mind I'm burning out the sludge. Don't know if it's really the case. Sometimes, once you shut down, it is difficult to start it up -thus the reason to burn it out before shutting down.

CATransplant · Jun 9, 2005

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

I always take a nice joyride around the lake after I've been trolling, keeping to the normal circulation pattern and away from fishermen. That way, even if I didn't do so well with the fish, I can enjoy my ride and blow the crud out of the engine.

Moody Blue · May 4, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Well the problem still persists after teardown and rebuild. During the process I converted to electric start. Compression checked out at 115/110 so I left the pistons and rings. Replaced exhaust cover gaskets, bypass cover gasket, powerhead gasket, lower crankcase seals & o-ring, new waterpump, rebuilt carb & set float level, rebuilt fuel pump. The inside of this motor was spotless, almost no carbon anywhere. After starting the motor (at the push of a button now

) and running on muffs, there was a steady stream of grey-brown oily sludge being discharged with the cooling water thru the prop exhaust. The pee stream was strong and clear. I do not believe this to be normal as is often stated on these forums. If that were the case our lakes would be covered in an oil slick after one month. Any thougts on where to look next. Its fishing time and I want toget this motor back into service. Where could the water get mixed with the combution gases to produce such a large amount of crap? Anyone?

rickdb1boat · May 4, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Compression checked out at 155/110

Something wrong with that picture. Head gasket or a crack. Rings most likely??

Moody Blue · May 4, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Rats, that was a typo. Should have been 115/110. Fixed it now.

rickdb1boat · May 4, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Have you actually had a chance to get out and run the motor on the water or just on the muffs after the rebuild?

ondarvr · May 4, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

I have a 9.9 and 6hp that have the same problem when I use some brands of oil, they run fine, no problems, but there is a milky goo that may drip from the motor after it's been run. It didn't happen on the big motors, just the kickers, they are used for trolling most of the time. When I switched oils the problem went away.

Moody Blue · May 5, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Only run the motor on the muffs. Had same problem last year when I put it away for the winter. Thick oily grey sludge from exhaust bypass and thru prop exhaust. Had the motor for 13 years and never did it before. Figured a seal or gasket had gone but everything looked OK when I opened it up. Replaced all BUT the upper crank seal. Never thought about the oil brand. Can't remember if I recently switched or not.

Moody Blue · May 6, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Here are a couple photos of the sludge. You are looking at the prop shaft and exhaust port. Notice the milkshake like crude at the bottom dripping out. This is what I have been trying to correct. Am I chasing my tail?

and

Comments anyone?

OBJ · May 7, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Rod, a couple things to keep in mind when running on "ears", the engine isn't working as hard as it would in the water because of lack of back pressure. So some unburnt carry over can be expected...a little more than usual. As Xcuseme pointed out in an earlier post, lot of slow trolling will do the same...low rpms for a long period of time. Basically that's what your doing on ears. You might also want to check the engine temp. If the block is running cold, combustion will be poor causing extra carry over. Will a change in oil brands help? Some say yes, some say no...I don't know.

jim_in_day · May 7, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

I see that same stuff when my carbs are running too rich. When I leaned everything out (by setting floats correctly and adjusting pickup timing, my exhause changed to black like it's supposed to be, When was the last time the carbs were gone thru?

ezeke · May 7, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

What do your spark plugs look like?

tiller7104 · May 8, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Just a thought from the peanut gallery, did you replace your thermostat? And is your choke working properly? I had a problem with my 40 where it ran way to cool, trolling is surely going to load your engine up.... but if it is running to cool that will just compound the problem !! Just a thought

Moody Blue · May 8, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

All good thoughts. Carb was just re-done, float set to factory spec. Low speed idle adjustment set to just under 1 1/2 turns out from seated. Seems that temperature may be a problem. Did not change the t-stat and it is original from 92. Perhaps its time. Plugs are new so its too soon to tell much from them. Last season they ended up moist and black. Hope to get the motor on the boat soon and run it on the lake under load and see what happens. How can I check for proper operating temperature?

DJ · May 8, 2006

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Rod, Do this. See link below. http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000016

Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

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