HELP need on Merc 50HP

[mrmamiller]

We're on a fishing trip in Canada. No technical support available, no stores, etc. One of the boats came in yesterday with problems. Motor is an older Merc 50 HP. We're guessing the motor is from the '80's. Identification on the motor says "Classic Fifty". Serial number is 0B136469. We can't find a valid model number. Motor has 4 cylinders. Boat owner says that a lot of parts have been swapped around over the years.

The problem: The motor is spewing a sizeable quantity of foamy white sludge from the exhaust ports which are located just below the cowling. This sludge shows up all over in the water and makes quite a mess. After trolling, there is white foamy sludge dripping down all over the leg of the motor. The motor smokes quite a bit. Mix is 50/1 TCW-3. All spark plugs look OK, so we have ruled out a blown head gasket. Plugs are surface gap, whatever Merc spec called for.

Any idea what could be causing this? Normal after 3 hours of trolling?

Think we can run it this way??

 

[racerone]

Head gasket can not blow , there is no cylinder head on those motor !------------Possibly a ruptured diaphragm on the fuel pump.-Possibly a leaking float valve in one of the carburetors.----If water is really cold it might be normal.

 

[Big Fish Billy]

Double check your measurements when putting the fuel together. I just had a friend buy a 4 stroke, and after 25 years of mixing fuel for 2 strokes, forgot and felt the need to continue doing it....had about the same symptoms as you.