LINES GP-FUEL INJECTION 4P9660 - Caterpillar

3176B (9WK) Marine EnginesHorsepower ratings of the smaller marine propulsion engines are increasing. In large displacement vessels with deep marine gear reductions, these engines may stall when shifting from forward to reverse.
Any size marine engine could potentially have this problem as horsepower ratings increase. If these engines are installed in vessels longer than 15 m (50.0 ft) with gear reductions greater than 2:1, they may not produce enough power when shifting. Even at low vessel speeds, when at low idle, the engines may not be able to overcome the load of reversing the propeller and coming up to speed in the opposite direction.A trolling valve can be added to the marine gear and an electronic control can be added to vessels with a single lever control that will allow the propeller to smoothly stop and reverse directions. An electronic control such as Mathers ClearCommand MS 549 uses the trolling valve to allow sufficient time for the propeller to stop, reverse directions and the engine to come back to speed without overloading and possibly stalling the engine.
The Mathers ClearCommand MS 549 control functions as follows:
* When the control lever is reversed, the engine is either at low idle or slows to low idle.* The trolling valve oil pressure is reduced to minimum, allowing the clutch to slip.* The forward gear clutch is disengaged and the transmission is shifted into reverse.* Within two seconds the trolling valve oil pressure increases to maximum and the clutch engages.* There is a speed boost feature that allows the engine to increase to a 21% duty cycle, approximately 900 rpm, during the two second pressure increase and clutch engagement.* When the trolling valve oil pressure reaches maximum pressure, the reverse gear clutch is fully engaged.* Engine speed then returns to the previous cruising speed indicated by the position of the control lever.The Mathers ClearCommand MS 549 control also has a programmable time delay feature that allows the vessel to slow during crash reversals. This feature senses vessel speed and adjusts the time delay accordingly. This allows full crash reversals without clutch damage or engine stalling throughout the operating range.
The Mathers ClearCommand MS 549 control uses a dual actuator within one enclosure, (one for each engine). The Master Station has a switch for mode selection. In trolling mode, the first 15 degrees beyond the forward or reverse detent position is used to position the trolling valve. The remaining 50 degrees of control lever travel is for the speed range.
On the 3176B, the engine trolling feature should not be used or pin 8 connected to the J1 connector when using the Mathers ClearCommand MS 549 control. The speed signal could be re-scaled and prevent the engine from reaching the desired rpm. For more information on the Mathers ClearCommand MS 549 Control, contact:Mathers Controls Inc.
675 Peas Road
Burlington, Wa 98233-3103
U.S.A.
360-757-6265
Fax: 360-757-2500