ONAN Generator Question

[Larry46]

2004 Winnebago Vectra 40AD

I have an Onan 8000 "I think" Diesel Generator and since the unit is completely covered in a metal case I can't tell whether it has it's own starting battery or not.

Does the generator use it's own starting battery "located inside the case" or does it use the chassis starting batteries? Mine are brand new and working fine.

I just had the generator serviced at Cummings South and when I went to start it I followed this procedure:

1. press the stop "down" on the start switch until green light comes on "green light did come on"
2. pressed the start switch for a few seconds and it just made some weird sounds but did not start

I then repeated and got the same results.

I tried one more time but held the start button down and after about 10 seconds the starter kicked in and it started and ran fine.

Is this normal?

[trackman]

They may have not primed the Gen good enough to get all the air out. You probably finished that job for them. Every Onan I have had has started off the house batteries

[Steve Ownby]

Originally Posted by Larry46

2004 Winnebago Vectra 40AD I have an Onan 8000 "I think" Diesel Generator and since the unit is completely covered in a metal case I can't tell whether it has it's own starting battery or not. Does the generator use it's own starting battery "located inside the case" or does it use the chassis starting batteries? Mine are brand new and working fine. I just had the generator serviced at Cummings South and when I went to start it I followed this procedure: 1. press the stop "down" on the start switch until green light comes on "green light did come on" 2. pressed the start switch for a few seconds and it just made some weird sounds but did not start I then repeated and got the same results. I tried one more time but held the start button down and after about 10 seconds the starter kicked in and it started and ran fine. Is this normal?

Pretty normal. The Onan uses one bank or the other of the coach batteries. Logic would dictate the generator start from the chassis batteries but I have discovered that that is not always the case.

When you press the stop switch the fuel pump is running to pressurize the fuel lines. When you press the start, the Onan goes through its pre start checks and may turn the glow plugs on if the genset is completely cold.

You did right. It will start in its own good time, just keep holding down that start switch.

[cbeierl]

In your Vectra the generator will start from the coach (house) batteries.

[Old Scout]

Just to clarify--as I recall. Holding the stop button down will engage the fuel pump to clear excessive air in the fuel system [eg following a repair]. Under normal start conditions, you simply push the start button--the Onan will go thru its start routine to prime the fuel pump, activate glow plug, and engage starter. Warm or cold, you shouldnt have to push the stop botton first. But I could be wrong--mine is an 03 era 7500.

[gfs1943]

Previous posts from Steve, Chris, and Trackman are correct. Most Winnebago coaches use the house batteries. Pushing the "Stop" side of the start/stop switch engages the fuel pump to prime the lines. After priming, if the unit is cold, you may have to hold the switch in Start for several seconds while the glow plugs are activated. Then it should start.

On a recent trip, my generator lost prime due to low fuel level (about 1/4 tank) and going uphill on a steep bridge. After I refueled, it took numerous tries to get the genny going. I would hold the switch in prime (Stop position) several seconds, then hold it in Start. It would crank over; eventually started firing then dieing, finally started and continued to run. It's been fine ever since.

[Larry46]

Thanks everyone,

I was worried something might be wrong with my Onan. Turns out to be normal behavior.

Thanks again

[Rossi6998]

On my 2013 Sunstar, it takes my Onan 4000 about 8-10 seconds before it starts. I prime it first and it always starts, just takes that long.