Low output

[kblaksley]

Hi,

I've been chasing low alternator output for the second season now.

Boat is a 98 Sea Ray 190BR with Mando alternator system

I had to replace the alternator two years ago for noisy bearings. Output was fine at the time. I purchased a factory re-manufactured unit from local marine max. (Big Bucks)!

All seemed OK at the time but not as strong as original. I mean at higher electrical loads causing voltage to drop be low 10 volts.
Fan, Nav lights, Stereo with amp, deep cycle recharge etc...

I had the original units bearings replaced and reinstalled only to find no output at all. So I took original unit back to be repaired and same thing.

So back to the replacement unit.

I cleaned all grounds, connectors plugs etc.. with no change.

Still hear lots of static in speakers and voltage drops to 10 volts with anything more than 20 amp draw. (10 volts verified with fluke meter) 20 amp draw verified with inductive clamp type ammeter connected to fluke.

Any suggestions?

How hard to convert to single wire delco marine unit? Never had a bit of trouble out of Delco system.

Thanks in advance for any suggestions or help on the matter.

Kevin

 

[Don S]

Re: Low output

If you have two known good alternators installed and neither works, then changing to a different kind of alternator is not going to cure the problem. You would probably have 3 alternators that won't charge.
It's time to find out what the problem really is.

Is the belt tight?

While running the engine at 12 to 1500 rpm, use your meter and see what the voltage is at the battery.
Also check right at the main B+ termianal of the alternator.

Might want to head up to the Adults Only sticky at the top of this forum and have a look at #1. We really need to know what engine package you have, not what type boat it's in.

 

[180shabah]

Re: Low output

While running the engine at 12 to 1500 rpm, use your meter and see what the voltage is at the battery.
Also check right at the main B+ termianal of the alternator.

Voltage should be the same. What is the condition of the charge line and it's connections at each end.

 

[kblaksley]

Re: Low output

If you have two known good alternators installed and neither works, then changing to a different kind of alternator is not going to cure the problem. You would probably have 3 alternators that won't charge.
It's time to find out what the problem really is.

Is the belt tight?

While running the engine at 12 to 1500 rpm, use your meter and see what the voltage is at the battery.
Also check right at the main B+ termianal of the alternator.

Might want to head up to the Adults Only sticky at the top of this forum and have a look at #1. We really need to know what engine package you have, not what type boat it's in.

Engine is Mercruiser 5.7 liter with Alpha One / Gen 2 drive.

Found a troubleshooting guide for the Moto charging system. Looking like grounding issue. The guide suggests that I should have between 1.5 to 2.5 volts with ignition switch on at excitation terminal. I am getting 2.0 volts with no load and less than .5 with higher load. I was grounding my meter at negative post of battery during this reading. I then grounded my fluke meter directley on alternator and voltage remained at 2.0 volts during no load / high load test. Not sure what that means at this point but my thoughts are that I should have the same reading no matter where I ground it Ahy? LOL.

Belt is tight and getting 14.2 volts with no load at battery and drops below battery voltage (11.2vdc or so) during higher load conditions. Fan, Electronics, lights, Captains Choice etc.... Same reading at output terminal at alternator.