So, I have a 91 FC (mostly stock, but lowering springs and rims and aftermarket exhaust), I'm totally new to rotary, have owned in the past.. I've owned this for 2 years, bought it and sat for those 2 years. I turned it on a week ago to see if it starts, I used Aaron Cakes write up on "removing from storage" it turned on fine, ran until operating temperature, sat steady mid marker on temp gauge, every other gauge looked good, ran pretty rough but stayed on, turned it on every other day after that, I checked fluids, oil was brown gunky stuff so decided to change oil and give coolant flush to get fresh fluids running through system. I changed the oil, no problem. I open all drains for the coolant flush, including the 14 mm block drain under the spark plugs, ran water through all hoses to clean up the brown stuff, I go to change the thermostat and there was no thermostat, just a clear O ring gasket, which I found strange, so I put in a Atkins thermostat and gasket with some RTV sealant, put everything back together, filled with Zerex Asian coolant. Go to start the car and starts pretty rough with white smoke, stalls about 10 seconds later, I restart more white smoke but runs a little longer, I decide not to continue just in case I did something wrong by putting in a thermostat when it didn't have one originally. So questions I have should I start it again? See if smoke clears? Should I take thermostat back off, see if it runs as before? Should there be a little gap on thermostat gasket and block? Coolant seals blown? Why was there brown gunky stuff in oil? Recommend rebuild? I was planning on rebuilding prior to trying to start it, but wanted to see if I can enjoy it before I send it, also can someone recommend a good rotary shop for a rebuild near Chicago?

 

A lot going on here. By brown gunk, do you mean darker than the oil or more of a milkshake appearance? White smoke and not idling could be a blown coolant seal. Try this, pull the plugs out and hold the gas all the way to the floor; this will open the throttle plates and cut fuel. Have someone with a flashlight watch the spark plug holes as you crank it. If any coolant or water comes out, you need a rebuild 100%. How does the oil look now? is it like pancake syrup or is it more like a milkshake? Any milkshake indicates water/coolant getting into the oil and it's time for a teardown. Alternately, you could pressurize the system with a cooling system tester. Any pressure drop with no external leak indicates a failed coolant seal.