Sarges12
Member
- Mar 7, 2018
- 53
- Boat Info
- 290 Sundancer 2001
- Engines
- 5.0 EFI Mercruiser w/Bravo III Drives
Some history first...
This past winter I did a complete cooling system maintenance overhaul on my 2001 Merc 5.0 EFI engines with Bravo 3’s. I replaced risers, spacers, manifolds, raw water pump (kits), circulating pump and thermostats. The boat was launched 3 weeks ago. On the trip to the slip I noticed the temp gauge on the starboard motor would climb slow to about 180° then go back to 160°. It did this constantly for the 20 min ride. This has never done this before. It still does it while idling in the slip but everything feels cool. I used an infrared gun shooting all areas of the block, thermostat housing and circ pump. Nothing I find alarming.
I’m concerned with the fluctuating temp gauge. So I started back tracking. I tried a new thermostat and temp sending unit. No difference. I pulled the raw water pump and inspected that and reinstalled. Tried swapping thermostat housing from the port motor as someone said it could be the housing. Nothing changed. I even bought a new temp gauge...still fluctuating.
I’m beyond done trying to figure out what the heck is going on.
At this point do I try another new circulating pump or even change the raw water pump kit again? It was even suggested doing a short haul and pull the drive back off and inspect the water gasket on the drive.
Has anyone ever had this issue? Suggestions before I turn it over to the marina?
This past winter I did a complete cooling system maintenance overhaul on my 2001 Merc 5.0 EFI engines with Bravo 3’s. I replaced risers, spacers, manifolds, raw water pump (kits), circulating pump and thermostats. The boat was launched 3 weeks ago. On the trip to the slip I noticed the temp gauge on the starboard motor would climb slow to about 180° then go back to 160°. It did this constantly for the 20 min ride. This has never done this before. It still does it while idling in the slip but everything feels cool. I used an infrared gun shooting all areas of the block, thermostat housing and circ pump. Nothing I find alarming.
I’m concerned with the fluctuating temp gauge. So I started back tracking. I tried a new thermostat and temp sending unit. No difference. I pulled the raw water pump and inspected that and reinstalled. Tried swapping thermostat housing from the port motor as someone said it could be the housing. Nothing changed. I even bought a new temp gauge...still fluctuating.
I’m beyond done trying to figure out what the heck is going on.
At this point do I try another new circulating pump or even change the raw water pump kit again? It was even suggested doing a short haul and pull the drive back off and inspect the water gasket on the drive.
Has anyone ever had this issue? Suggestions before I turn it over to the marina?