Kohler Diesel Gen Won’t Start

[Papabrer]

, I need some trouble shooting suggestions. I have a Kohler gen on my boat, don’t know and cannot find the model number, still looking but it is old and a bit rusty.

Bought the boat a little over a year ago and everything has run great until about a month ago. I had not used the gen in about 3-4 weeks. Tried to start it and got nothing. Thinking dead battery, I was able to get it started by jumping with main ship battery. Ran fine for about 30 min. Shut it off, tried to start and dead again. Replaced the battery and it started right up again.

Left for a week, came back and dead again. Won’t even turn over, get a small whining noise when the start button is pressed. I know it’s old but would really like to try

 

[brewster16]

I don't really know your experience level....... but, you must properly preheat the generator by depressing the toggle in one direction until blinking indicator shows it's properly preheated and ready to start. Then depress toggle the other direction for a minimum of 20 seconds until it starts. If your doing this already then move on.

 

[dtfeld]

My guess is a bad alternator on the generator. It’s not charging the generator battery. Pull it and have it bench tested.

 

[Papabrer]

Thanks guys, appreciate the ideas. I am starting it properly. Alternater tests OK and battery is getting charged when gen is running.

I believe I have narrowed it down to starter solenoid or wiring to the starter motor and solenoid. I am going to re-terminate all the wiring and see if that corrects the issue.

 

[Papabrer]

Further information, turns out my issue was corroded (due to previous owner painting everything) wiring to the solenoid. All cleaned up now and gen working fine.

New question, generator alternator is hot to the touch when he set is off. Is this anything to worry about. Don’t know if it was hot previously or not as I never checked it.

 

[techmitch]

Further information, turns out my issue was corroded (due to previous owner painting everything) wiring to the solenoid. All cleaned up now and gen working fine.

New question, generator alternator is hot to the touch when he set is off. Is this anything to worry about. Don’t know if it was hot previously or not as I never checked it.

Put a DVOM on the battery for the gen. and or the large terminal on the back of the alt. to ground while it's running and then when you shut it down, monitor the reading.

 

[dtfeld]

Further information, turns out my issue was corroded (due to previous owner painting everything) wiring to the solenoid. All cleaned up now and gen working fine.

New question, generator alternator is hot to the touch when he set is off. Is this anything to worry about. Don’t know if it was hot previously or not as I never checked it.

They do get hot, but if just charging up the generator start battery, should be normal.

 

[Papabrer]

Follow up question. What purpose does an alternator on a marine generator serve? I use the genset to generate 120v power to my on board battery charger which charges all the batteries. Seems a bit redundant to have the alternator charging the same battery?

 

[ttmott]

Follow up question. What purpose does an alternator on a marine generator serve? I use the genset to generate 120v power to my on board battery charger which charges all the batteries. Seems a bit redundant to have the alternator charging the same battery?

It is redundant - that's a good thing; engine alternators - the same.
Alternators should get warm if the battery is charged and in good shape. If the alternator is getting too hot to touch then either the battery is very low on charge or has a shorted cell. Alternators will also get hot and kill batteries if the rectifier diodes have failed to ground - which can and does happen.

Put a DVM set on AC Volts across the battery and measure the ripple (the Alternating Voltage) when the alternator is running - if it is greater than 6 millivolts then the charging device is failing.

 

[Papabrer]

Thanks much, failing/failed alternator replaced.