minuteman62-64
Lieutenant
- Joined
- Apr 12, 2011
- Messages
- 1,350
'82 30 HP Mariner. Fitted w/cylinder head temperature gauge. Since I installed the gauge it has read 145 F at idle/low speed and drifted up to just shy of 180 F when running at 3500-4000 RPM, all the while with a good stream from the tell-tale.
Friday took it for a run on Mission Bay. Started with about 15 minutes of crusing at about 3800 RPM. Head temperature as described previously - sitting at just shy of 180 F when we slowed to enter a "no wake" area.
Chugging along at the 5 mph limit (about 1500 RPM on my boat) I noticed the temperature rising. Hit reverse to clear any kelp and moved on. Still rising, all the while with a good stream from the tell-tale. Checked anyways for kelp over the water intake, but it was clear. Temperature slowly began dropping, but rose again as we speeded up after leaving the controlled area. Went all the way up to the 220 F mark.
We were going to do some fishing anyways, so I throttled down and idled over to a promising area and shut down to drift. Fished for about an hour, occaisionally starting the motor to re-position. Temperature stayed at the 145 F mark while underway.
On the way back I thought I'd check a little further. Went to the ski/jet boat area and cranked it up to 3800 RPM for about 10 minutes. Temperature was a steady 145 F. Stayed that way all the way to the dock.
So, now, after an overheating incident, I seem to have better cooling than before. Checked the cylinder head temperature sensor this morning and it is fast in place, no loose connections or other visible problems.
Any thoughts on what is going on? Intermittent thermostat operation? Clog in cooling system that got blown out after awhile? Other?
Friday took it for a run on Mission Bay. Started with about 15 minutes of crusing at about 3800 RPM. Head temperature as described previously - sitting at just shy of 180 F when we slowed to enter a "no wake" area.
Chugging along at the 5 mph limit (about 1500 RPM on my boat) I noticed the temperature rising. Hit reverse to clear any kelp and moved on. Still rising, all the while with a good stream from the tell-tale. Checked anyways for kelp over the water intake, but it was clear. Temperature slowly began dropping, but rose again as we speeded up after leaving the controlled area. Went all the way up to the 220 F mark.
We were going to do some fishing anyways, so I throttled down and idled over to a promising area and shut down to drift. Fished for about an hour, occaisionally starting the motor to re-position. Temperature stayed at the 145 F mark while underway.
On the way back I thought I'd check a little further. Went to the ski/jet boat area and cranked it up to 3800 RPM for about 10 minutes. Temperature was a steady 145 F. Stayed that way all the way to the dock.
So, now, after an overheating incident, I seem to have better cooling than before. Checked the cylinder head temperature sensor this morning and it is fast in place, no loose connections or other visible problems.
Any thoughts on what is going on? Intermittent thermostat operation? Clog in cooling system that got blown out after awhile? Other?