- Oct 6, 2006
- 12,155
- Boat Info
- 1996 450DA
- Engines
- 3116 Caterpillars
For those of you with 44DA's, 44DB's, 48DA, and similar boats with CumminsMercruiser QSC engines, there appears to be an unusually high incidence of overheating due to accessory drive belt problems. If your engines do not have adjustable idlers, be sure to carry spare belts.
This is the belt that drives the circulating pump on the engine. In some cases, the drive belt stretches a little, then slips, but in other cases, due to the design of the engine and belt routing around t he spring loaded idler, the drive belt is thrown off the engine. Its hard for it to turn the water pump when its laying in the bilge under the engine.
The critical point here is that when the belt slips or is thrown off, the engine will overheat immediately since the coolant is no longer circulating. In the length of time it takes you to recognize the overheating because of a warning from the engine control system, slow down, climb down from the bridge, open the engine hatch and identify the cause of the overheating, you can burn up an expensive engine.
Diesel engines hit hard due to the compression ratios and there some vibration particularly at low speeds. The cause of the belt problem above is nothing more than inadequate maintenance and failure to check and periodically tighten the drive belt as needed. As the belt stretches, it will slip....if it is allowed to stretch enough, engine vibration will throw the belt off its pulleys.
This is not a warranty issue since belts are wear items and are excluded. There is no recall since there is no defect.
This is just a reminder that belt stretch and tension on these, and potentially other diesels, is a critical maintenance item. It is also a maintenance check that most Sea Ray dealers can and often do overlook as they do routine annual service. Save being caught in a busy seaway trying to deal with an overheated engine and learn how to adjust your belts and carry along the correct tools for the job............and carry a pair of extra accessory drive belts along in your spares kit.
This is the belt that drives the circulating pump on the engine. In some cases, the drive belt stretches a little, then slips, but in other cases, due to the design of the engine and belt routing around t he spring loaded idler, the drive belt is thrown off the engine. Its hard for it to turn the water pump when its laying in the bilge under the engine.
The critical point here is that when the belt slips or is thrown off, the engine will overheat immediately since the coolant is no longer circulating. In the length of time it takes you to recognize the overheating because of a warning from the engine control system, slow down, climb down from the bridge, open the engine hatch and identify the cause of the overheating, you can burn up an expensive engine.
Diesel engines hit hard due to the compression ratios and there some vibration particularly at low speeds. The cause of the belt problem above is nothing more than inadequate maintenance and failure to check and periodically tighten the drive belt as needed. As the belt stretches, it will slip....if it is allowed to stretch enough, engine vibration will throw the belt off its pulleys.
This is not a warranty issue since belts are wear items and are excluded. There is no recall since there is no defect.
This is just a reminder that belt stretch and tension on these, and potentially other diesels, is a critical maintenance item. It is also a maintenance check that most Sea Ray dealers can and often do overlook as they do routine annual service. Save being caught in a busy seaway trying to deal with an overheated engine and learn how to adjust your belts and carry along the correct tools for the job............and carry a pair of extra accessory drive belts along in your spares kit.
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