88 DT200's not charging

[R_Andersen]

I have twin 88 DT 200's that don't appear to be charging properly. When the motors are running I only get between 12.2 and 12.6 volts at the batteries no matter what speed the motors are run at. I tried to check the voltage going to the rectifier (I forget the wire colors, maybe red and yellow?) and I got about 14 volts AC when I ran the motors over 3000 rpm. I checked all connections and fuses and everything sems fine.<br /><br />I'm wondering what other test I can perform to verify if it's a chraging coil, stator, or rectifier/regulator problem? Also, what voltage should these motors produce while running? I assume 14-15v at sppeds above idle...<br /><br />Thanks for any help,<br />Rob

 

[Silvertip]

Re: 88 DT200's not charging

12.2 volts at the battery means the batteries are definitely not charging. It's also highly unusual that both would be bad however. Have you had problems with the batteries running down? What caused you to check them. Are you relying on the console voltmeter for the voltage reading or using a VOM. The console gauge may not be accurate. It may be time to check and clean battery cable terminals thoroughly (both ends). High resistance can cause electrical problems.

 

[R_Andersen]

Re: 88 DT200's not charging

Yes, I have problems with the batteries running down. I am also using a VOM for all readings. The batteries are all brand new and all cables, connections, etc are in good shape. I purchased this boat last year after it had sat for 6 years. I've gone through everything and have it running great now. I'm assuming the motors have never been charging since I got the boat, but I have no idea how long it's been like this or what could have caused it.<br /><br />I can seem to get the voltage to increase to about 12.6V by bringing one of the motors up to over 3000 rpm but the other motor causes no change no matter what speed it's run at. Obviously 12.6V is still to low, but one motor does seem to produce a very slight charge current.<br /><br />-Rob

 

[Silvertip]

Re: 88 DT200's not charging

Its really odd that both regulators would be bad but then anything is possible. Using your VOM, check the voltage at the large positive terminal on the starter solenoid (the one on which the positive battery cable is connected to. The output of from the regulator (probably a larger red wire)is normally connected to this terminal. If voltage is higher than 12.6 the regulator is ok and the charging current is just not reaching the battery. Make sure the battery cable connections are clean, shiny, and tight. Finger tight wing nuts are not tight enough. Keep trying and check back with what you find.

 

[R_Andersen]

Re: 88 DT200's not charging

No, It's definately not an issue with bad connections. All cables are new and I've also checked the voltages at the motor and there is no major difference. I'm wondering if maybe the previous owner burned up both regualtors by switching off the batteries while it was running. I'm wondering if there's a way to test the regulator/rectifier and the chaging coil and stator.<br /><br />Thanks again,<br />Rob

 

[Silvertip]

Re: 88 DT200's not charging

Aha - so this is not a new problem? And you probably hit on the cause of the apparent failure. Do your tachs work? They get their signal from the regulator so if they don't work, thats an indication the regulator is not functioning. Generally there are two inputs from the stator to the rectifier portion. The wires are usually the same color or one may be solid, the other will likely be the same color but may have a tracer in it. Disconnect those wires and the output wire. Using your VOM (set for resistance) measure across the two input wires. You should get very high resistance. Reverse the probes and do it again. Should get the same reading. If you get a very low or "0" reading, the rectifier circuit is bad. If everything is good so far, repeat the above process but measure from one input wire to ground, then reverse the probes and repeat. Then do the same thing again for the other input wire. In one direction you should show high resistance and when reversing the probes you should see low resistance. If readings are the same (high or low) regardless which way the probes were connected, the rectifier is again shown bad (shorted). Without a schematic of your rectifier/regulator I can't help you test the output side. I'm guessing that you will find shorted diodes in both units.

 

[R_Andersen]

Re: 88 DT200's not charging

Thanks for the info. Both tachs do work fine, but I will try testing the rectifier this weekend and let you know what I find.<br /><br />Thanks again,<br />Rob

 

[fridays]

Re: 88 DT200's not charging

Check your fuses. 1 powers up the ign. switch and the other is strictly the charging system.

 

[R_Andersen]

Re: 88 DT200's not charging

Fridays, where would the fuse be located? I did check the 15 amp fuse at the engine near the regulator and it was ok on both engines. I think it was inline on a white wire but it's beena while? Is there another fuse somewhere that I might be missing?<br /><br />Thanks again,<br />Rob

 

[R_Andersen]

Re: 88 DT200's not charging

I did some more troubleshooting on the no charge problem and could use some more advice. It turns out one motor does have a good charge and one has no charge. <br /><br />I checked the rectifier per the manual's direction and it tests ok. I also put an AC volt meter on the red and yellow leads from the charging coils and I get 8 volts at idle up to 20+ volts above 3000 rpm so I'm assuming i'm getting the proper AC voltage and the rectifier is ok (per the previous tests). I'm assuming that leaves the voltage regulator which is internal to the rectifier I believe? I've checked all the fusees and wiring and everything else is ok.<br /><br />Any other adive would be appreciated.<br /><br />Thanks,<br />Rob

 

[aabfeh]

Re: 88 DT200's not charging

Rob- You mentioned an on/off/both battery switch. Have you checked the voltage being supplied to both sides of the switch? Check everything inside the switch.

 

[R_Andersen]

Re: 88 DT200's not charging

Yes, it's definately not an issue with any of the switches or wiring. I have checked the voltage right at the white charge lead from the rectifier/regulator and don't get any voltage insrease when the motor is running. I only get battery voltage (12.4-12.6).