Thanks to help from all the great people here at iBoats, I finally got my boat in the water this afternoon for a shakedown cruise. Had a couple issues to start with, but once she warmed up, it was like a brand new engine just as a rebuild should. I only pushed her to about 3500 RPM today and she ran like a top........ Until we went to head back in.
Had stopped in a cove, engine off, for roughly an hour or so, long enough for the engine to cool most of the way back to cold. Got ready to head back to the ramp. Cranked her up, and she fired good. We start easing in, and after it got up to around 140 or so I went ahead and gave it the throttle up to the 3500 RPM I said I ran it at. Out of nowhere, my temp gauge skyrockets after cruising for little to no time. Immediately shut her down, and when I did, it dieseled for a few seconds, and finally shut off. This concerned me a little with it already being hot (gauge read 200+, but gauges lie sometimes too). Would not crank again until it cooled off. I have pulled the water pump, it's good. Took plugs out one at a time and spun her over, no water in cylinders. Therefore, no water in oil. This is where it gets tricky. I had an epiphany and checked the thermostat, rusty as all get out. This was previously a saltwater boat/engine, and I have no clue why I did not think to look at the thermostat before even running it. Took some work to even get it out to test. Dropped it in boiling water, and pulled it out, and sure enough it was opening.
Could it have been stuck, and by my prying and prodding, I "unstuck" it? Any other suggestions as to why the sudden overheat when it was running fine the rest of the day? For those who aren't keeping score in my saga, this is a 3.0 GSPHUB fresh rebuild.
Had stopped in a cove, engine off, for roughly an hour or so, long enough for the engine to cool most of the way back to cold. Got ready to head back to the ramp. Cranked her up, and she fired good. We start easing in, and after it got up to around 140 or so I went ahead and gave it the throttle up to the 3500 RPM I said I ran it at. Out of nowhere, my temp gauge skyrockets after cruising for little to no time. Immediately shut her down, and when I did, it dieseled for a few seconds, and finally shut off. This concerned me a little with it already being hot (gauge read 200+, but gauges lie sometimes too). Would not crank again until it cooled off. I have pulled the water pump, it's good. Took plugs out one at a time and spun her over, no water in cylinders. Therefore, no water in oil. This is where it gets tricky. I had an epiphany and checked the thermostat, rusty as all get out. This was previously a saltwater boat/engine, and I have no clue why I did not think to look at the thermostat before even running it. Took some work to even get it out to test. Dropped it in boiling water, and pulled it out, and sure enough it was opening.
Could it have been stuck, and by my prying and prodding, I "unstuck" it? Any other suggestions as to why the sudden overheat when it was running fine the rest of the day? For those who aren't keeping score in my saga, this is a 3.0 GSPHUB fresh rebuild.