What causes this grey emulsion?

[adam1961]

Just did the basic tune up items on a 1957 Evinrude 10.
Gearcase held 10psi for 24 hrs so I didn’t do anything other than change the oil which came out clean.
Good hot spark that will jump 3/8 gap.
It starts OK in the tank but want to run with the choke on. It seemed too rich though. When I pulled it out of the tank, I had this grey emulsion drain from the front of the water pump. It smells more like fuel than gear oil.

How far out should I start with the needles on this motor?

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[phil-b]

gas/oil mixture mixed with water; worse when running rich

[frankr]

Worse when running in a tank.

Worse when running at slow speeds

Worse when weather/water is cold.

Worse when running rich.

Much worse if running on one cylinder.

Some oils do it more than other oils.

Bottom line: The glop is a symptom, not the problem. In fact, there may not be a problem at all. Some discharge is normal.

[adam1961]

It must be too rich. How lean should I start with the HS and LS needles. I need to check my fuel quality first, and then have another go at it.

[Mumbles]

I’d start with about 1 1/2 turns out on the lo speed needle and maybe one turn on the hi speed just to get it started. As soon as it starts it will be rich so the hi speed will need to be adjusted right away. The final hi speed setting seems to vary from around 1/4 to 1/2 turn out. It isn’t much.

How’s your fuel mix? Fuel mix seems to get richer for me after sitting around for a while. I never add extra oil when it’s sitting so the gas must be evaporating away.

[phil-b]

For whatever it’s worth (likely nothing!) whenever I get an engine on a boat for real/final adjustment, wide open, to adjust the high speed needle, it seems like it takes several major (quarter turn?) tweaks to lean it out (speeding up each time) before I get it too lean (losing speed and/or a cough).

[adam1961]

I will have another shot at it tonight. I have a tendency to start too rich on motors that are fresh rebuilds or have say for a long time. I will get fresh fuel and see what it does.

[fleetwin]

I don’t understand the poor running symptoms you mentioned, you seemed to say that you had to run it with the choke out somewhat, but it was too rich….
In any event, you will get that kind of emulsion slop drooling out when the engine is not running correctly. Put it on a boat and give it a good run like everyone has said, dial in the high speed needle before adjusting the low speed needle.

[adam1961]

Last night I mixed up some fresh 16:1, swapped the plugs and closed up both HS and LS needles significantly. She runs great now. One of the better runners that I have had in a long time.

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