I have an '07 Marlin with Yamaha twin 250 four strokes. The engines have 460 hours and are serviced by the dealer once per year.
Last summer I had been running at 41 hundred rpm's for about 1.5 hours offshore towards the Albacore tuna grounds out of San Francisco, and the right engine (sitting forward in captains chair) went into automatic shutdown mode due to overheating.
I shut down, raised the engines, and cleaned the intake's (was not much there to clean), let it rest, then re-stared and went on our way without further incident (unfortunately, no tuna caught that day).
Prior to shutting down, the gauge on the left engine was reading in dead center, while the right engine was "resting" in the 3/4 point (the last bar on the gauge before the last segment).
I mentioned this to my dealer, and he did a thorough maintenance, which included new water pumps, thermostats, as well as plugs and the typical lubrication. The odd thing was that the computer check of the engine did not report any incident where the engine had shut down, when it certainly did.
Since then, I have not had any issues, but I do watch the gauges closely on every trip now. I have noticed that the temp at times, while running at 41 hundred rpm, on both engines will move up over the halfway point on the water temperature gauge to the 3/4 level towards the last remaining "segment" on the gauge (the hottest setting).
Finally the question, is this normal or typical? Or, should I be concerned? Shouldn't the typical reading be in dead center of the gauge at all times?
I have searched the Yamaha guide, but could not find any information regarding the "normal" running mode.
Any thoughts are welcome.
Tim
Last summer I had been running at 41 hundred rpm's for about 1.5 hours offshore towards the Albacore tuna grounds out of San Francisco, and the right engine (sitting forward in captains chair) went into automatic shutdown mode due to overheating.
I shut down, raised the engines, and cleaned the intake's (was not much there to clean), let it rest, then re-stared and went on our way without further incident (unfortunately, no tuna caught that day).
Prior to shutting down, the gauge on the left engine was reading in dead center, while the right engine was "resting" in the 3/4 point (the last bar on the gauge before the last segment).
I mentioned this to my dealer, and he did a thorough maintenance, which included new water pumps, thermostats, as well as plugs and the typical lubrication. The odd thing was that the computer check of the engine did not report any incident where the engine had shut down, when it certainly did.
Since then, I have not had any issues, but I do watch the gauges closely on every trip now. I have noticed that the temp at times, while running at 41 hundred rpm, on both engines will move up over the halfway point on the water temperature gauge to the 3/4 level towards the last remaining "segment" on the gauge (the hottest setting).
Finally the question, is this normal or typical? Or, should I be concerned? Shouldn't the typical reading be in dead center of the gauge at all times?
I have searched the Yamaha guide, but could not find any information regarding the "normal" running mode.
Any thoughts are welcome.
Tim