merc150
Petty Officer 2nd Class
- Joined
- Jun 17, 2013
- Messages
- 110
Hey guys I have a 2003 mercury 150 saltwater CARB motor with maybe 350-400 hours on it. I have been having problems for the past month with it running at about 180-185 at 4000 rpms. It will run at 140 to 160 or so from idle to mid rpm range then it gets up to 180-185 at 4000 to 5000 rpms. I have changed the water pump about 5 months ago (mercury pump kit), I recently gutted the thermostats and changed the poppet valve and its still doing it. The water flow though the telltale is very strong. (before I changed the poppet valve I had the opposite problem it would run hot when going slow through a no wake and at mid throttle then cool down to 160 at full throttle). The guage (Teleflex sahara) and temp sending unit are new. I do not get a overheat alarm (yes it has been checked and is working). Before this past month the motor has always ran at 160 degrees no matter what. I fish a lot of redfish tournaments so im trying to get this figured out as soon as possible. One other thing both of my mercury dealers are telling me 180 is way to hot and that the warning alarm should come on at about 190 degress BUT my seloc mercury manual says that the warning alarm should turn on at 232-248 degrees I don't know which one to believe. I also removed the oil pump about a year ago and I have been mixing the oil 50:1. Other than that the motor is very strong and runs great. ANY help will be greatly appreciated!!!! THANKS