Twin Disc issues

[Champ3555]

Good morning all. I am desperate to find information on how to repair my 2001 570 Voyager. First let me say this a beautiful well maintained, updated boat with around 900 fresh water hours. The specifications are as follows;

Engines-Cummins QSM11 535s Serial # Port 35016246, Starboard 35015841
Transmissions- Twin Disk

My issues are:
1) Port transmission seems to have a vibration that throws the engine into limp mode and will not allow speed of more then 1400 rpm. Throttles are slow to respond on both sides and I have to move half way up to get response.
2) Starboard engine will not exceed 1800 rpm.
3) The transmissions do not shift into gear smoothly. Slight bump when moved into drive mode

Known and recent repairs and service calls:
1) The previous owner replaced the starboard transmission which may account for the vibration due to misalignment???
2) Both drive shafts, props, bearings and rudders have been replaced or repaired due to a cable wrapping around the starboard prop.
3) Local Cummins technicians were paid $1,500.00 to diagnose engines under sea trial to determine RPM issues. They were unable to get a connection to the ports during this service call. I never received a report, only a bill.
4) Local marina (who is a Carver dealer) maintenance crew is completely clueless and the above incident with Cummins has me suspicious of any repair crews.

Any and all responses and recommendations would be greatly appreciated!!!!

Topic

[Champ3555]

Good afternoon Tony. Thank you very much for your reply and I apologize for loosing track of this website and not responding. I would love to update you on my lack of RPM issues. Cummins finally completed their work by replacing the starboard ECM and some other minor issues. The Engines are in good working order and under 1,000 hours. I wanted to get you the information you asked for and see if you can respond with possibilities for repairs.

1. The transmissions are Twin Disk model MG-5081-A
2. I believe they are electronic shift
3. Engines are Cummins 535 QSM11
4. The boat is a 2001 Carver 570 Voyager and I have owned it 4 years. It did reach 2300 RPM when I first purchased it. I don’t run it that fast. It started the low RPM on the starboard side about a year after I bought it. No damage or anything unusual happened to cause it. Boat has been well maintained by me.
5. Gear control system is Ec200. I will get you a picture when I return to the boat this Wednesday
6. When Cummins techs were programing the new ECM during a sea trial, the computer kept bouncing from the starboard to the port. I understand these are closed systems and that should not happen.
7. Port engine will make 1800 to 1900 RPM and occasionally higher but I do not overpower the starboard when maneuvering. Starboard will not exceed 1400 RPM
8. There are two helm stations and a remote station

Thank you for any advise I can pass on to my mechanic 

[Tony Athens]

Mike,

Way too many thing missing here to even have a chance to guide you on where to go from here..

1–Exact model of TWIN DISC transmission and gear ratio

2– Thransmisson is mechanical or elec shift?

3-Exact model of the engine / gear control system is ? Post good pictures of the heln staion shown the controls

4-History of engine / vessel operation as to max RPM, vessel speeds, etc.. In other words, did the vessel ever operate properly since you owned it? Properly would mean the engines made 2300 RPM , etc etc etc..

Start with that.

Tony

[Author]

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