1 hour ago, JasonK said:

I would bet the loose strainer caused bad suction, and that caused the overheat/purge of coolant.

Agree with this. I had a friend that had his transom hose insert slightly loose and it caused the same symptoms. He tightened the cap and everything was fine. You have to make sure there is no way to introduce air into the cooling system, both fresh water and closed side.

I would check for loose propeller hardware, poor engine alignment, and v-drive fluid condition first.  The drive plate is attached to the engine flywheel which which is spinning whenever the engine is running, not just when the transmission is in forward gear.  Noise from a damaged drive plate tends to be most noticeable at idle, in neutral, and will go away as the engine throttle is increased.  Drive plate damage often occurs from propeller collisions.  The v-drive, propshaft, and propeller are only spinning when the transmission is in forward or reverse, but do not turn when in neutral. 

BEEP CODES — the 4 maintenance items that can trigger the beeper are:

• High engine water temperature (>203*)
• Low oil pressure switch (<6 PSI at switch; NOT dash gauge/pressure sending unit)
• High transmission temperature (>140?*)
• A diagnostics trouble code

Sorry, I may have given you bad advice on the knock sensor.  Removing the transmission temp and oil pressure sensor will stop the beeping if those are bad, (which I would do next to eliminate as possibilities) but removing knock sensor may trigger the same alarm just as if it was bad, so I believe that may still be the culprit. 

You could try disconnecting the transmission temp sensor and oil pressure sensor next to see if one of them is failing.  Next step would be reading the code that it's throwing...it could be lots of things like TPS sensor, etc.  I'll try to remember to put my old code reader in my tool kit to lend you if I see you out there again. 

OG wakestter FB page said the same thing. So did my friend. Do you know if it's complicated.

25 minutes ago, justgary said:

I think that is definitely more true of ethanol than toluene due to the lower energy density of ethanol.

If I did my math correctly, raising 87 octane to 91 octane with toluene (at 114 octane) requires (91-87)/114 = 3.5%, or 4.5 ounces per gallon.  So one gallon of toluene per 28 gallons of 87 pump gas.

I don't think that's right.   I always used this method:  Sunoco mixing octane link. One gallon of 114 toluene in 28 gallons of 87 octane would only net you 87.93 octane.   You'd need roughly 5 gallons of toluene in 24 gallons of 87 octane to get a 91 ish octane 29 gallon blend.   Depending on where you source it from, toluene can be anywhere from $15 to $50/gallon, aka it doesn't make sense to use as bulk octane booster.