mstailey
Active member
- Joined
- Dec 5, 2005
- Messages
- 156
- Hatteras Model
- 43' DOUBLE CABIN (1970 - 1984)
I'm having a bit of trouble understanding what Cummins is recommending for operating RPM on my VT-903-M1. Note my CPL plate states advertised HP is 340
I can't scan / transfer from my Marine Operations Manual to a readable document so I'll type it in for view.
========================================================
Table 1: Cummins Marine Diesel Engine Ratings
VT-903-M1 Pleasure 340 hp @ 2800
Light Duty 295 hp @ 2600
Continuous 255 hp @ 2300
Boat and Ship Engine Ratings (Ref. Table 1)
------------------------------------------------
Pleasure Boat Rating
This is the maximum rating and is intended for use in variable load applications where the average load factor does not exceed the continuous rating and where full throttle operation does not exceed 15 minutes duration in any one hour.
Light Duty Commericial Rating
This rating is intended for use in applications where the average load factor does not exceed the continuous rating and where full throttle at this rating does not exceed eight hours total in any 24-hour period
Continuous Duty Rating
This is a 24-hour continuous rating and is intended for use in applications requiring uninterrupted service at full throttle operation at this rating
Governed Speeds
All Cummins engines are equipped with governors to prevent speeds in excess of maximum of predetermined lower speed rating
The governor has two functions: First, it provides the exact amount of fuel needed for idling when the throttle is in idling position. Second, it overrides the throttle and shuts off fuel if engine rpm exceeds the maximum rated speed.
Operate At Reduced RPM for Extended Cruising
For normal cruising operation, maintain engine rpm at approximately 85 percent of rated rpm. See Table 1, Engine Ratings. This will give adequate power as well as economical fuel consumption.
Engine governors are normally set for reduced rpm or the fuel pump at reduced fuel rate for continuous-duty operation.
========================================================
So, if I understand the above I should be running at 2380 RPM's (.85 X 2800)
Right?
I can't scan / transfer from my Marine Operations Manual to a readable document so I'll type it in for view.
========================================================
Table 1: Cummins Marine Diesel Engine Ratings
VT-903-M1 Pleasure 340 hp @ 2800
Light Duty 295 hp @ 2600
Continuous 255 hp @ 2300
Boat and Ship Engine Ratings (Ref. Table 1)
------------------------------------------------
Pleasure Boat Rating
This is the maximum rating and is intended for use in variable load applications where the average load factor does not exceed the continuous rating and where full throttle operation does not exceed 15 minutes duration in any one hour.
Light Duty Commericial Rating
This rating is intended for use in applications where the average load factor does not exceed the continuous rating and where full throttle at this rating does not exceed eight hours total in any 24-hour period
Continuous Duty Rating
This is a 24-hour continuous rating and is intended for use in applications requiring uninterrupted service at full throttle operation at this rating
Governed Speeds
All Cummins engines are equipped with governors to prevent speeds in excess of maximum of predetermined lower speed rating
The governor has two functions: First, it provides the exact amount of fuel needed for idling when the throttle is in idling position. Second, it overrides the throttle and shuts off fuel if engine rpm exceeds the maximum rated speed.
Operate At Reduced RPM for Extended Cruising
For normal cruising operation, maintain engine rpm at approximately 85 percent of rated rpm. See Table 1, Engine Ratings. This will give adequate power as well as economical fuel consumption.
Engine governors are normally set for reduced rpm or the fuel pump at reduced fuel rate for continuous-duty operation.
========================================================
So, if I understand the above I should be running at 2380 RPM's (.85 X 2800)
Right?
