80hp Merc gray sludge from prop

[rookie456]

I have a 1980 80hp Mercury that I have rebuilt. I have been running the motor trying to link and sync and getting the carbs adjusted. The first three times a ran the motor in a tub, after I finished there was a black ring in the tub from unburnt fuel I'm guessing. The last time I ran it on muffs, and it left milkshake looking gray sludge out of the prop exhaust. I am wondering at what point does water and exhaust mix? I took the lower unit off and ran the engine with a garden hose feeding the water tube. Engine ran good, I stll had gray sludge dripping from the exhaust housing after I shut the engine down and shut the water off. I have checked the spark plugs multiple times for signs of water, but I only see fuel on the spark plugs.
Is the gray sludge normal at the prop, or should I be concerned. The exhaust ports under the lower cowl show no sign of gray sludge from there.

 

[emckelvy]

Sounds like you have leakage on the exhaust side, or a leaking powerhead base plate, causing water and exhaust to mix. You may have to pull the powerhead to find out where the water is coming from.

With the powerhead off, if you can see "milk" in the exhaust passages, you've either got leaking gaskets, or a perforated exhaust baffle plate. When you did the rebuild, did you renew those gaskets and what were the bolts torqued to?

HTH...............ed

 

[rookie456]

During the rebuild, I replaced the exhaust baffle water jacket gasket and the 2 exhaust cover gaskets. I torqued the bolts to 200 inch lbs in three stages. I did not replace the drive shaft housing plate gasket or the exhaust tube gasket, because I didn't disassemble that area. I replaced the power head gasket, and I notice now that the power head gasket looks a little skewed. I don't see any exterior water leaks, I am hoping it is the power head gasket, I really don't want to open the exhaust cover again.

 

[rookie456]

I pulled the power head today. The power head gasket looked like it was sealed good. So then I pulled the exhaust cover off, looks like the exhaust baffle water jacket gasket is leaking. When I put it together the first time, I used johnson gasket sealing compound, the thick brown stuff. Does anyone have a suggestion of what I should use as a sealant for the gaskets?

 

[Faztbullet]

If your talking about the inner baffle against the exhaust ports , that is put on dry and the bolts resiweld epoxyed and torqued.

 

[rookie456]

I got a new water jacket cover, all new gaskets and bolts for the exhaust cover. Put it all back together and ran the engine for about 15 minutes with a garden hose feeding water right into the water tube. I let it idle at 900 rpm for 15 minutes, sounded good the whole time. Shut it off, once the bulk of water drains from the motor, gray foamy mixture starts dripping from the exhaust tube. Some how exhaust and water are still mixing.
I ordered a new exhaust cover and a new baffle plate with gaskets to try to seal it up again.
Am I missing something, could the water be coming from somewhere else? I check the spark plugs each time I run it, I don't see water droplets on the spark plugs, it's hard to tell if it looks steam cleaned cause the plugs and Pistons are new.
Is there an easy way to tell if it's the lower crank seals, which are both brand new?
I've torqued all bolts to the specs in my manual.
Any suggestions on what I might be missing would be appreciated.

 

[Dukedog]

gray is usually unburnt fuel/water mix.. black sludge is usually fuel/exhaust and water.....