1998 force 75 hp 2 stroke chocolate milk coming out of exhaust

Hello all
So my engine started "surging" about 150 rpm at WOT and Im down 4-6mph at top speed. I changed fuel line, filter and pulled carb and cleaned very well.
I went out and ran it again still same problem. Only ran at WOT for 5 miles and when I pulled the boat this time I had chocolate milk colored sludge pouring out of the exhaust on back of engine. Nothing coming out of prop though.
Im kinda leaning twords head gasket but I have no water on plugs that I can tell. Im really just looking at a place to start troubleshooting and any other advice is greatly appreciated.
Thanks in advance.

Compression test needs to be done.----Checked fuel pump diaphragm ?----Thermostat checked ?

Im getting a compression tester this morning.
Have not checked anything yet. This just happened yesterday so Im jumping on it today. What should I look for in the pump? the motor pumps water well but I will inspect the thermostat as well.
Thank you

Compression results?

Compression checked perfect 125-127 psi on all 3 cylinders.
It wound up being the diaphram in the fuel pump broke and was sucking extra fuel into the engine and pouring raw fuel from the exhaust.
I rebuilt the pump and all is well!!!
Thanks

Glad it works.