mando alternator question

[bigbob_FTW]

Ok, I've installed a new mando alt on my mcm120. I'm only getting 12.5V to the battery. Voltage ground to red wire is 12v. When running, the voltage at the orange wire jumps off the gage. This should be 13.5-14.5 give or take? the orange wire connects to a junction block on the starter. Could this be bad. I get 12V at the batter side and it jumps off the charts again on the alternator side.

 

[Don S]

Re: mando alternator question

Disconnect the orange wire from the alternator and the starter and see if it checks ok with an Ohm meter.

 

[bigbob_FTW]

Re: mando alternator question

Thanks don, I'll check that one as soon as i can.

 

[bigbob_FTW]

Re: mando alternator question

Thanks Don, that's the clue I needed. It was the terminal block (fuse?) on the starter. I hooked it direct and it i'm getting 14v at the battery. Should I now install a fuseable link between the starter and alternator?

 

[Don S]

Re: mando alternator question

Just replace that 90 amp fuse. The wire is only good for 50 to 60 amp alternators, and the fuse is there to protect against excess amperage, which it obviously had. To prevent a fire from overheated wires, keep the fuse.
The Merc PN is 79023A91 and costs around 25 bucks.