Chocolate milk spooge from exhaust?

[ShoestringMariner]

I just noticed a bunch of chocolate milk looking spooge coming from the exhaust of my 1976 650 Merc. Last time I was out, we trolled through about 20L of fuel. I never opened it up to top speed. Could this be from loading or not running up to temperature?

I checked the lower unit oil and it is brand new, all three plugs look decent except the bottom one is slightly discolored. Just a little darker and a little wetter.

it also never ran better. Trolled slow all day with only one brief act up.

​​​​​​​Thanks in advance

 

[Scott Danforth]

unburned fuel. use the throttle and open it up

 

[ShoestringMariner]

Huge relief, thank you!

 

[tommarvin]

No disrespect Aritha F got to love her.
This isnt the lower unit,gear lube you wont know if its leaking until you change the 100 % synthetic stock marine gear lube "aka" amsoil. Or do a pressure /vacuum test.
This is your head gasket leaking water into the cylinders,please dont run the motor until you replace the head gasket, do a compression test/leak down test.to be sure, there is a trogue inch pounds order, #1,#2,and so on.Better get the mercury manual,that walks you through it step by step, and a inch pound torque wrench from HF tools
You need to get a head gasket first.clean the old gasket material off well. you got this.

 

[Chris1956]

Of course, he doesn't have a removable head on that motor....

You might check your fuel pump diagram for a slight leak. That would allow raw fuel into the water.

 

[racerone]

Mr Tom. ---That motor does not have a head gasket !!

 

[Scott Danforth]

No disrespect Aritha F got to love her.
This isnt the lower unit,gear lube you wont know if its leaking until you change the 100 % synthetic stock marine gear lube "aka" amsoil. Or do a pressure /vacuum test.
This is your head gasket leaking water into the cylinders,please dont run the motor until you replace the head gasket, do a compression test/leak down test.to be sure, there is a trogue inch pounds order, #1,#2,and so on.Better get the mercury manual,that walks you through it step by step, and a inch pound torque wrench from HF tools
You need to get a head gasket first.clean the old gasket material off well. you got this.

Ahhhh.....no.

 

[racerone]

I would like some of what Mr Tom is drinking or smoking !

 

[Scott Danforth]

I would like some of what Mr Tom is drinking or smoking !

....

 

[ShoestringMariner]

Whoa, confused here! Am I getting pranked?

wouldnt water getting in kill the fire in that hole, cause terrible running and show up on a plug? It seriously never ran better. The cold snap and 55degree water seemed to agree with it(??)


thanks Chris1956, I will look into it.

I’m hoping it’s nothing needing deep digging immediately. It’s getting a refurb this winter. Hope to use it until seasons end (another 4 weeks)

 

[Scott Danforth]

on two strokes, if you dont run them hard after hours of idling, the extra fuel/oil that isnt burning gets into the exhaust, mixes with water and becomes the chocolate puddin you have shown.

older two strokes are more prone to this with a straight pre-mix vs oil injection (motors need less oil at idle/low load)

your fine, go boating, use the throttle a bit to bring the temps up after you idle along trolling. no need for a WOT blast, however bring the revs up to about 3k (under load) for about 3 or 4 minutes to clear it out.

you could also use a kicker to troll

 

[ShoestringMariner]

on two strokes, if you dont run them hard after hours of idling, the extra fuel/oil that isnt burning gets into the exhaust, mixes with water and becomes the chocolate puddin you have shown.

older two strokes are more prone to this with a straight pre-mix vs oil injection (motors need less oil at idle/low load)

your fine, go boating, use the throttle a bit to bring the temps up after you idle along trolling. no need for a WOT blast, however bring the revs up to about 3k (under load) for about 3 or 4 minutes to clear it out.

you could also use a kicker to troll

Thanks again, yes a kicker is planned for the future when funds allow

 

[Scott Danforth]

if you watch craigslist, you can find good deals this time of year. you may have to drive a few hours, however mid 80's kickers are about $150-$200

 

[tacx]

+1 for what Scott said .Just unburned fuel in the exhaust from a lot of ideling. I have a 1970 merc that will do the same thing if i troll for long periods and dont open it up going back to the dock.
Tom