204FSX MIke 0 Report post Posted May 23, 2020 Just purchased this used 204fsx. 204 hrs. Runs amazing. Just noticed that the cooling temp gauge is not working. Worked the other day. What should I check? I’m pretty tech savvy so should be able to trouble shoot with your help. merc 4.3L is not getting hot. Exhaust is cool to the touch... hope someone can shed some light. First step I’m thinking is to check the temp sender wire. But not sure where it is? thanks all. happy boating Share this post Link to post Share on other sites
204FSX MIke 0 Report post Posted May 26, 2020 Well the temp gauge drops to 100 degrees when running over 3000 Rpm. When I slow down and just cruise it pops back up to around 160 degrees. Any idea what’s going on? Share this post Link to post Share on other sites
Kelly from Jax 0 Report post Posted May 26, 2020 I've got a similar problem so I'm following this thread. My mechanic is going to hook up some analog gauges while I run to figure out what is going on. Either a bad sensor or the raw water impeller is damage to where when you are running a idle it isn't spinning and providing cool water through the engine. I get a solid alarm when it happens... Share this post Link to post Share on other sites
204FSX MIke 0 Report post Posted May 28, 2020 Thanks Kelly! I appreciate your response and look forward to your reply. My temp alarm is not sounding off so I am not over heating. Have a great day! Share this post Link to post Share on other sites
GetAway 0 Report post Posted May 29, 2020 When was the last time the impeller was changed? I had an impeller that was 2 years old and my temp gauge dropped to 120 no alarms. I have the 2000 Volvo 5.7 G??. I changed my impeller with a new Volvo unit and my temps returned to 158 - 160 and stays there at idle and 3000 - 3500 rpms. I've read the unit should be changed every 2 years. Share this post Link to post Share on other sites
Kelly from Jax 0 Report post Posted May 30, 2020 The mechanic hasn't come to see the boat yet. We've been getting storms every afternoon. Hopefully next week. Share this post Link to post Share on other sites
