On Jun 14, 12:33 pm, Capt John wrote:
On Jun 13, 11:29 am, Michael Noe
wrote:

I just purchased an '01 Maxum 3500. When I start the port engine with
the generator running, it stalls the generator. Does anyone have any
idea what would cause this? Both engine batteries are new, the third
seems OK.

TIA.

It's eather an electrical problem, or a fuel problem. If the port
engine and the generator share the same fuel feed that could be the
problem, if they don't, toss that idea. Now your generator should have
it's own alternator, which supplies it with it's own 12 volt power. If
that alternator isn't working, and the port engine and the generator
12 volt supply are tied together, the voltage drops when the port
engine cranks that should shut down the generator. A quick test is to
start the generator, and disconnect the generator from the battery. If
it stalls, the alternator isn't putting out any power. The battery
switch for the generator might not be set up so as to protect the
alternator if someone switches it to the off position while it's
running. If the alternator is bad just pull it off and bring it to a
rebuild shop, they can fix it better than new for a whole lot less
money. Let me know what you find.

John

It's not going to be fuel related. The gas in the generator carb
would keep it running for a minute or two even if you completely cut
off the fuel feed. The most likely scenario is the one Wayne posted
to start with. The voltage is getting pulled down by the engine
starter and some iffy connections are resulting in there not being
enough voltage to run the generator ignition so it stalls.

Your "quick test" is a good way to destroy an alternator by the way.
Without a battery as a load many alternators will put out enough
voltage to destroy the diodes in them. It exceeds the reverse voltage
rating of the diodes.