Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

[OBJ]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Rod...what is the year of the 9.9? Older 9.9/15's had a flat area on top just forward of the head. At idle, you should be able to lay your fingers there for several seconds before have to remove them. The temp should stay near constant. If the engine feels cool after idling for a while, then likely the t-stat needs changed out.<br /><br />Even on the newer 9.9's, if the t-stat is bad and failed open, you can touch the block and head just about anywhere and it will feel just warm or cool to the touch.

 

[tiller7104]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Ditto what OBJ states its a good old school way of checking. I just troubleshot my buddies 9.9 this way. He had grey sometimes black sludge from his exhaust, it poped up at the beginning of this season and according to a good local mechanic here.... Hope it is this easy!

 

[Moody Blue]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

From what I can recall, after say 10 minutes of idling on the muffs, the head was only warm to the touch and the exhaust port cover was cold. The telltale stream was also cold. Think I will replace the t-stat anyways just to be sure, afterall, its been in there for 14 years. Thanks for everyones input.<br /><br />DJ, I don't think I need to do a decarb. When I took the motor apart there was not a sign of carbon buildup except for a little on the tops of the pistons. The rings, ports and exhaust passages were clean. Quite surprising.

 

[redcajun18]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

that kinda looks like gear lube with oil in it doesn't it?

 

[F_R]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

You indicate that your motor runs well and idles well. So, it ain't broke and quit fixing it.
You asked if you are chasing your tail. In my humble opinion, yes you are. Think about it. You put oil in the gas. The mixture goes through the engine. The gas burns. The oil does not burn at that low combustion temperature at idle. If it did it would be VERY lousy oil and would not protect at high temps at high speed running. So where does the unburned oil go? Out the exhaust ports. Then it mixes and emulsifies with the cooling water that has gone through the powerhead and is now cooling the exhaust. The emulsified mixture is what you are seeing. Some brands of oil seem to emulsify more than others, but it's there.

If you are (rightfully) concerned about dumping that crud in the lake, I suggest you use Castrol Full Synthetic TCW-3 outboard oil. They claim it's bio-degradeable. I do know from my personal experience and testing that the oil slick dissipates much faster than regular TCW-3, and it smokes less.

 

[jimmbo]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Hmmm. foamy goo

 

[DHPMARINE]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Naw,let's fix it till it's broke.

By the way,original post was June of 2005.I doubt he's still waiting fo an answer.

DHP

 

[Bruce San]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Good advice DHP! I'm going to start on mine when I get home.

 

[samo_ott]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

A good way to check the engine temp is to use one of those infrared thermometers. They're getting prety cheap these days.. Or use one that some parents have for their kids ears! It's better than guessing!

 

[Harker]

Re: Oily sludge from exhaust 9.9 Evinrude REVISITED with PHOTOS

Might be a year old post..but it came to my attention at an opportune time. I'm having the same issue with a 1967, 9.8 Merc. When I had the lower off I looked up the exaust housing and it seemed the gooo was starting clear up in the exaust area of the powerhead. I just ordered gaskets for the exaust cover, tranfer port cover, powerhed to midsection and midsection to lower pan. It started after rebuilding the carb and putting a new fuel pump on it.