We purchased 2000 3500 open with 370 Cummins last fall. our first outing was to bring the vessel home. (410 Statute miles). I have 2 questions. We installed 5 new batteries before our trip. Both banks of batteries would only charge to 12.5V while under power. When at the dock with the charger on they would charge to 13.5V. My past experience has been that the 13.5V is more the normal. Any thoughts?
My second question is - the tachometers get erratic after about 20 minutes at cruise speed. The starboard engine doesn't record the actual Hours of run. This has apparently has been a problem for some time as this engine has nearly 80 hours less than the port. At the survey when the question was asked why, the owner (second) said that it had been that way since he purchased it (2 years). Has anyone experienced anything like this ?
13.5v is normal. Not being an electrical kinda guy, I would wait for others to chime in on this one
Are the tach digital? I'm guessing they are not. First off, tachs are terribly unreliable unless digital IMO. I would consider replacing them with Aetna Digital Tachs. LOVE these tachs!
Are both tachs getting erratic? If just one swap them and see if the issue follows the tach. If it does then you know it's a gauge problem, if it doesn't then you need look down stream.
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You are correct with your assumption that the tachs are Analog. Yes both tachs are erratic but the Starboard is much more so and the only one not recording the hours.
Thank you for the info on Aetna Digital Tachs, I will check them out, sounds like a good option.
Aetna tachs are ugly IMO, digital red led's on a 2000 is just not pretty, will always look like a replacement. True analog are not always perfect but they are repeatable and look better IMO. BUT, as far as the tach's bouncing around, sounds like you have a ground issue. I had the same problem and one of the ground wires on the sensor boards was causing intermittent buzzers and the tachs to jump around.
As far as the batteries, verify voltage at the battery with battery charger both off and on. Verify voltage when running engines at battery charger. Voltage gauges at the helm again are not entirely accurate but you are looking for a change when running and absolute numbers are not needed. There are 2 relays behind the helm that activate when you start the engines and they are for the voltage meters, if they have corrosion on them then they will show inaccurate, low or unstable. If you take some voltage readings I can guide you through as I had to troubleshoot various little issue like this on my 2000 3500 Open and finally got everything worked out.
Thanks Tom, I really appreciate your input. I will take the voltage readings and check the relays as you suggested and see if I can figure this thing out. I have this feeling I will be back asking for help.
Thanks again
John
Do you have the original manual. If so, in the back are all the schematics for all the wiring on the boat from the factory. If you know how to read schematics (if so I apologize for asking) then these are super helpful. Helped me troubleshoot the relay, wiring for the alternators (previous owner mis wired) and bilge pumps which again the previous owner rewired for some odd reason. Let me know.
Tachs - Swap them and see if the problem follows the tach or stays with its side. At least you will eliminate a part of the system with this test and make it easier to find the problem.
Batteries and charging - Your vessel was originally set up with Gel Batteries, Bal-Mar alternators and the shore charger was set to charge Gel batteries. Gel batteries and flooded cell batteries are not interchangeable. They require completely different charging cycles. A gel charging system will under charge a flooded cell battery and a flooded cell charging system will cook a gel battery.
The Bal-Mar alternators are designed to charge gel batteries. If you wish to switch to flooded cell batteries, you will either have to change out the Alternators or replace the regulators (most likely less expensive to just go to a traditional alternator) with ones designed to charge flooded cell batteries. The house charger should have a switch on it that would allow you to simply flip a switch depending on what types of batteries you are using.
Did you put Gel batteries in the boat or flooded cell (traditional lead/acid)?
An FYI - AGM batteries, even though they are not a traditional flooded cell can be used in place of flooded cell batteries, but are not a replacement for Gel batteries.
Chris, Some of the information you listed is not quite correct. For example, all AGM batteries are not created equal and have different charging profiles. Odyssey ( remarketed by Sears as their premium marine battery) have an almost identical profile as a flooded cell while other are drastically different. The Bal Mar alternators in my 2000 3500 Open have Charles regulators which have about 7-8 different profiles and can charge almost any battery including AGM. I called Charles (also the maker of the battery charger on board) and talked to them about charging AGM batteries with the original alternators, regulators and battery charger. I have Odyssey AGM batteries installed and Charles was able to set me up with the correct dip switch settings on the regulator but the battery charger has no adjustments. Looking at the charging voltage from the battery charger, it works very well with the AGM's. And remember the alternators do not charge the batteries but the regulators do and that is what sets the voltage for charging, not the alternators at least on mine.
I have had some pressing issues that demanded my attention, so I am just getting back to you. Today I went to the boat with the intention of troubleshooting the tachometer problems. When I attempted to start the engines, they would turn over but would not start. In the process, I learned that the prestart heater was not functioning; even though the switch checked out o.k. When overriding and getting the heater working, the engine would start and continue to run until release of the "Start" position of the ignition switch, which removed power from the relay and caused the engines to stall. This is identical on both engines. I only have schematics for the OEM portion of the vessel; no information whatsoever on the Cummins 6BTA5.9 m3 engines. The ignition switches checked out o.k. I reset all of the circuit breakers that I am aware of and the problem persists. I hired an electrician and a diesel mechanic check out the problem and they were not successful at locating the problem and require a schematic that continues from where the OEM leaves off and the engine starts. There appears to be something (perhaps a fuse) between the two and we have no way of knowing where it is at without the laborious task of attempting to follow it all the way back. I have placed a call to Tiara today and left a message but have not received a response. I have also contacted Cummins to inquire of them if they have schematics and they informed me that this would be the responsibility of the OEM manufacturer?
The batteries that were installed, are identical to the ones that were replaced (wet cell or lead acid). This could explain the charging variance. I would appreciate your thoughts, ideas or suggestions while I await response from Tiara.
Pre-heaters are not required to run or start. As a matter of fact I have disabled mine and dont' run them as the only thing they do is put a strain on the charging system. It sounds like the fuel solenoid may be closing which in turn will shut the engine down, actually this is how the engine is shut down. If you batteries are not being charged, the solenoid will not stay open and will shut down the engine. You can try to tie the fuel solenoid open to see if it continues to run after you release the start but it sounds like the charging system has a fault someplace since the batteries are not being charged. You say the preheat was not working? How did you know it was not working and how did you fix that. PreHeaters take up an enormous amount of current and will suck a battery down quickly. I would disable the preheater and run without until you find the other problems first.
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