black oily substance dripping down the outside exhaust housing

[Melvin Hatcher]

I have a black oily substance dripping down the outside of the exhaust housing of my 1985 XP 150. <br /><br />Is it leaking outside the housing instead of thru the prop opening, due to a bad seal? <br /><br />The propeller opening is dry as a bone.

 

[93bronco]

Re: black oily substance dripping down the outside exhaust housing

is it in between the lower unit and midsec or is it high up at power head level?

 

[gss036]

Re: black oily substance dripping down the outside exhaust housing

Did you put an additive in your gas? Sounds like disolved carbon from the cylinders. When was the last time you decarbonized your engine? Do a search for "decarb" and you will find several formulas. I like Seafoam.

 

[Melvin Hatcher]

Re: black oily substance dripping down the outside exhaust housing

It is between the lower unit and midsec and drips down from the power head level. <br /><br />I have not put an additive in the gas. However, I did decarb the engine a couple of weeks ago. I have not really ran the engine real hard after decarbing. Mostly idling while crabbing. <br /><br />I would expect the black ooz to come out the propeller opening, not drip down the outside exhaust housing.

 

[Duck Loads]

Re: black oily substance dripping down the outside exhaust housing

This sounds like what I get when I run my gt150 on the muffs/garden hose. <br /><br />Be safe,<br />Duck L.

 

[rickdb1boat]

Re: black oily substance dripping down the outside exhaust housing

Unburned gas/fuel. May be running rich at low and idle speed. Pretty much normal. Make sure you run it full out on the water before you pull it out.

 

[Dhadley]

Re: black oily substance dripping down the outside exhaust housing

Its not uncommon for motors of that era to develop a crack in the corner of the exhaust housing right under the powerhead. It doesnt really hurt anything but it sure looks nasty. We have welded or epoxied a few and sometimes it works. Sometimes there is so much carbon in there that it didnt. Sometimes the carbon itself was sealing the crack and a good decarb job caused it to start leaking.<br /><br />The other thing to look at is the drain hose on the bottom of the air silencer base. Make sure its still connected and the hose isnt leaking.<br /><br />Good luck!

 

[AUGIDAWG]

Re: black oily substance dripping down the outside exhaust housing

Where does the oil from that drain hose go to?

 

[Dhadley]

Re: black oily substance dripping down the outside exhaust housing

The hose goes from the air silencer base to the front half of the block assembly. Down near the lower main bearing area.

 

[Melvin Hatcher]

Re: black oily substance dripping down the outside exhaust housing

This sounds interesting.<br /><br />All of my hoese are hooked up. But, let's talk about the recovery and recirc hoses. I thought all were the same, recirc hoses. I still don't understand the recirc system. Please explane.<br /><br />Thanks<br /><br />DoferGofer.

 

[walleyehed]

Re: black oily substance dripping down the outside exhaust housing

I have one question....Have you ran the same oil in this as always????????Have you changed brands for any reason?????

 

[Melvin Hatcher]

Re: black oily substance dripping down the outside exhaust housing

I have run Evinruide oil since 1985. However, I am considering the Wally-smart oil very seriously.

 

[walleyehed]

Re: black oily substance dripping down the outside exhaust housing

DoforGofer, don't know if you're joking with me on that response, but I have used XD-25 since it was available (J/E), and out of curiosity, I tried a gallon of Wally supertech.....I will never again run THAT oil in anything of mine-this is my personal experience/opinion. If you think your leg WAS black, the wally oil will double that mess.<br /> Stick with the Bombardier oils........

 

[Melvin Hatcher]

Re: black oily substance dripping down the outside exhaust housing

No joke, I have always used J/E oil. But, the price of Wally's supertech, is causing me to seriously consider Wally's product. <br /><br />My question is; how does the oily substance get on the outside of the exhaust leg? If it ran out of the propeller opening, I would expect that, for it to leak on the outside of the exhaust housing, do I have a crack or bad gasket somewhere?

 

[kenneths]

Re: black oily substance dripping down the outside exhaust housing

It's kicked back out of the intake in one way, but you could also have a bad gasket in some areas, and may even be the carb silencer box gasket...as this would be a place to start looking...the carb box drain tube going to the crankcase-i have seen this line come off at either end.<br /> I just recommended the J/E oils based on my experience-it (Supertech) changed my idle so dramatically it was unreal, but to keep the testing honest, I went (ran) back to XD-25, and after about 3 hours total, all symptoms cleared up...Thats what I'm going by-not hear-say.<br /> Good luck, and do what works for you!

 

[kenneths]

Re: black oily substance dripping down the outside exhaust housing

The lines you are concerned about have a double life, one, and the main one, is to eaqulize ambient pressure to help with a more even distribution of fuel delivery, and "balance" combustion in a correctly running engine...

 

[AUGIDAWG]

Re: black oily substance dripping down the outside exhaust housing

"eaqulize ambient pressure "<br /><br />Do you mean float bowl venting?<br /><br />I'm confused. (that is not uncommon)

 

[kenneths]

Re: black oily substance dripping down the outside exhaust housing

Ambient means "actual", as in berometric pressure. each cyl. has it's own pulse dependant upon ring-seal-as to the efficiency of the pulse.<br />Every cylinder is not the same, and a small vacume or pressure spike is partially eaqualized by these lines as a means to "open" the variables to be closer together for a somewhat smoother combustion.......

 

[Joe Reeves]

Re: black oily substance dripping down the outside exhaust housing

Dofer..... The 150hp engines, including the 1985 model had a rather thin powerhead to adapter gasket. This is most commonly refered to as a powerhead base gasket. This original gaskets OMC part number is 323214.<br /><br />There is a section of gasket between the exhaust passageway and the top front motor mount area. That thin gasket section blows away, allowing the oily unburnt combustion mixture to leak over to the top front motor mount area, after which it spills out and down the outside area of the exhaust housing (hsg between the powerhead and the lower unit).<br /><br />The cure is to replace that thin gasket with the new improved thicker gasket which carrys the OMC part number 333658. Sort of an asbestos reinforced gasket.<br /><br />This gasket can be identified even when it's installed by a tab that protrudes out the back of it. This tab can be seen quite easily sticking out at the bottom center portion of the exhaust baffle plate (the large flat plate between the cylinder heads).

 

[Melvin Hatcher]

Re: black oily substance dripping down the outside exhaust housing

Thanks Joe,<br /><br />This makes sense to me. Because, I see a small leak at the rear at the power head to adapter gasket tab that you mentioned. My engine has the gasket with a tab protruding from the back. However, that gasket is very thin, looks like a shim type gasket, probably no more than .002 to .005 thick.<br /><br />Is this gasket difficult to replace, if not I think I will wait until the next time I replace the water pump? <br /><br />However, not right away. In fact, It is not leaking nearly as bad as it done, when it was first started up after a 15-year rest period. I think I will concentrate on rebuilding the carburetors. I think they may need some attention.