Alternator

[dgetswet]

So Had a friend come down and he tested the batteries and alternator for me. Turns out the alternator only putting out 12-12.5 amps even under higher idle. My quest is I have a 2005 Perkins Sabre 300Ti. It have a Leece-Neville 90amp 12 volt alternator in it.

Has anyone had one of these? Has anyone had to change their alternator? Which did you choose. I have a feeling I over looked the most obvious of problems for a while.

[WillieC]

From what I have read, Leece -Neville is a very desirable brand. Others may have comments on how to check voltage regulator.

[dkirsop]

Take the alternator to an alternator shop. They will bench test it and determine if the problem lies with the alternator or the regulator.

You don’t mention if you have an internal or external regulator. If it is external you can bypass the regulator and energize the field winding in your alternator. The amperage should increase when voltage is applied to the field winding if the alternator is ok. This is a short term test and should not be done for more than a few minutes.

[Panhdjoe]

Just want to second what dkisop wrote, The low output could be due to a problem other than the Alt. its self. Putting battery voltage to the Field (often marked "F") terminal will cause the alternator to put out all it is capable of. the voltage and amps should start to climb immediately. Do not let the voltage go past about 15v as damage could happen.
As for the Leeceie, they are the best. most fire trucks have them. I would want to make sure it is a Marine grade alt. and if so I would run it if it physically fits.