Mercruiser 3.0 Overheating

[ImTheBiggerBoat]

1997 mercruiser 3.0 Alpha 1 gen II outdrive. Ran the boat around 3500 RPM's for an hour yesterday no issue. Hit the water in the afternoon and before exiting no-wake i noticed my newly replaced Faria Kronos temp gauge was reading 225. I shut the engine down, waited roughly 20 minutes then putted back to the house (10 minutes) and trailered the boat. Noticed the pick up hose on the outdrive had popped off with the hose clam still attached.

I've concluded that the boat was experiencing those temps for roughly 5 minutes before I noticed, we were in no wake the entire time. no smoke, did smell hot oil. Could anyone tell me what to look for or how to proceed? Oil change, new t-stat, etc...Thanks

 

[Scott06]

Put the hose back on or replace with new. This is the water supply hose up from drive. Hook it back up. Make sure water is coming up from outdrive to thermostat housing. Should have 3 qts every 15 seconds or so.
would just look for melted rubber components on exhaust(rubber boots and shutters) and watch for signs of blown head gasket like water in oil . It probably ok , biggest risk is rubber components in exhaust getting burn due to lack of water flow

 

[ImTheBiggerBoat]

Put the hose back on or replace with new. This is the water supply hose up from drive. Hook it back up. Make sure water is coming up from outdrive to thermostat housing. Should have 3 qts every 15 seconds or so.
would just look for melted rubber components on exhaust(rubber boots and shutters) and watch for signs of blown head gasket like water in oil . It probably ok , biggest risk is rubber components in exhaust getting burn due to lack of water flow

Ordering a new flapper, (second owner and no records of it being replaced). Also, i'm experiencing some "dieseling" on occasion so it's probably good peice of mind. Would you recommend an oil change? Also, can you comment on the temp thermostat I should have? I'm seeing both 175 degree and 140 as options. marineengine.com indicates a 140 degree when I put in my engine serial number.

Thanks

 

[nola mike]

Didn't think 175 was an option, either 140 or 160. Don't have your serial number so can't double check your work.

 

[ImTheBiggerBoat]

Didn't think 175 was an option, either 140 or 160. Don't have your serial number so can't double check your work.

Hmm, good info.
Serial #0W001775

 

[Scott06]

Hmm, good info.
Serial #0W001775

Double check this on the drop down menu for your engine there are two thermostat housing assembly listings split by serial number OLxxx and up is 160 thermostat

i have a 160 thermostat and engine runs about 170 per gauge …