Long post but wanted to put the details I know in the post.
My 2004 4.3 GXI-E (serial # 4012110736) overheats at higher RPM's. Can maintain half throttle and temp stays normal but after several minutes of running at 3/4 - full throttle, Overheat Alarm sounds and powers engine down. Have checked the thermostat housing with temp gun and is reading 190-200F.
I have replaced the raw water impeller, thermostat (have verified it opens by placing in hot water), replaced the temp alarm sensor (in tstat housing), have made sure tstat housing is clean and no debris or blockage.
Have replaced the pivot housing seal and o-ring in the stern drive, found a rubber cap on power steering cooler that was cracked and replaced it. The flush water cap has been tightened down. Feel that I am air tight, but maybe not?
Have verified the risers are clean.
I performed a test, not on purpose and honestly embarrassed to say this. But when I check the risers I forgot to tighten the hose clamps on one of the risers. Boated full throttle for about 10 minutes and never overheated. Once I stopped to check temps with temp gun I realized my stupid mistake. Got the water out of the boat, tightened the hose clamps and started to boat at full throttle again. I was only able to boat full throttle for about 3 minutes before over heat alarm sounded. Check tstat housing and was around 190-200.
I am lost on what to check/do next. Thanks in advance for reading the long post.
My 2004 4.3 GXI-E (serial # 4012110736) overheats at higher RPM's. Can maintain half throttle and temp stays normal but after several minutes of running at 3/4 - full throttle, Overheat Alarm sounds and powers engine down. Have checked the thermostat housing with temp gun and is reading 190-200F.
I have replaced the raw water impeller, thermostat (have verified it opens by placing in hot water), replaced the temp alarm sensor (in tstat housing), have made sure tstat housing is clean and no debris or blockage.
Have replaced the pivot housing seal and o-ring in the stern drive, found a rubber cap on power steering cooler that was cracked and replaced it. The flush water cap has been tightened down. Feel that I am air tight, but maybe not?
Have verified the risers are clean.
I performed a test, not on purpose and honestly embarrassed to say this. But when I check the risers I forgot to tighten the hose clamps on one of the risers. Boated full throttle for about 10 minutes and never overheated. Once I stopped to check temps with temp gun I realized my stupid mistake. Got the water out of the boat, tightened the hose clamps and started to boat at full throttle again. I was only able to boat full throttle for about 3 minutes before over heat alarm sounded. Check tstat housing and was around 190-200.
I am lost on what to check/do next. Thanks in advance for reading the long post.
