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Topic: Generator diesel/air bleed (Read 1074 times) previous topic - next topic

Generator diesel/air bleed

Dave,

I asked this question a couple of days ago, but it was buried within a multiple part topic and so it got overlooked. I've never changed the fuel filter on my generator.  When I do, do I have to prime the engine after installing the new filter?

Thanks for your input.
George Stoltz.  Retired from full-time living in a great Foretravel and now are back to living in a traditional sticks and bricks in Florida.

Re: Generator diesel/air bleed

Reply #1 –
When I changed the filter (as part of my extended diagnostics...) I did bleed the air out of the low pressure feed to the injectors, but I'm not sure it's necessary.
I think if you just fill the filter with diesel before you install, it should be fine.    (That assumes you have a spin-on filter that can be filled...)  Worst thing that can happen is that the gen will stumble a little before starting or be slow to start. 
Dave and Nancy
1999/2013 U270 36' Xtreme
Motorcade # 16774
2013 Subaru Outback
KD0NIM

Re: Generator diesel/air bleed

Reply #2 –
On my non quiet box 10KW PowerTech its supposed to be bled - only takes 2 wrenches and about 15 seconds.
 
Follow the fuel line out of the filter to the engine. Look at the fitting right there - it should kind of look like a nut with bolt on top of it. Hold the lower nut and loosen the upper bolt about 1/2 a turn. Push the preheat button. This not only energizes the glow plugs, but it runs your electric fuel pump for you. When the fuel runs clear with no bubbles, tighten the bolt and start your engine.
 
I can take a pic and post it if that would be helpful.
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT

Re: Generator diesel/air bleed

Reply #3 –
My 10K Genset in 96 U320 has two hoses going from genset to fuel tank.
One hose is feed and other is return.
Fuel is sucked via feed hose to the bottom of the genset tray with an Onan low pressure fuel pump.
Hoses then take fuel through a filter to the upper part of genset and into a fuel/air seperator.
Air and some fuel are returned to the fuel tank via return hose.
To bleed air, push preheat and fuel pump will run and return air to tank.

This air bleed back system is there because fuel pickup for generator is above the bottom of the tank so generator will not use all fuel leaving you stranded. Genset will stop because it runs out of fuel, but will restart easily when tank is full (or fuller).

I pulled the feed hose at the air/diesel seperator and put hose in a bottle to save the mess caused by cracking nuts on fuel line.
Wyatt
96 U320 40 WTFE, build 4943
84 Toyota Supra towd
2015 Jeep Wrangler towd
Victoria, BC, Canada

Re: Generator diesel/air bleed

Reply #4 –
Just read in the Isuzu manual that Morris posted, that the Isuzu engine is also designed to automatically bleed any air in the fuel system!
Dave and Nancy
1999/2013 U270 36' Xtreme
Motorcade # 16774
2013 Subaru Outback
KD0NIM

Re: Generator diesel/air bleed

Reply #5 –
Quote from: Dave Katsuki –
Just read in the Isuzu manual that Morris posted, that the Isuzu engine is also designed to automatically bleed any air in the fuel system!
Dave,
I suppose the question is "how much air" before it sputters and shuts off.  My Isuzu ran fine with a field supply of fuel but not with the tank supply.
 
Or, is the "bleed" feature available only once when changing the fuel filter or upon start sequence?  Then, when the engine fires up, air in the lines will not continuously run the engine.  Perhaps this is the reason the engine fires up and only runs for about 5 seconds? ??? ??
Peter & Beth Martin
No Forrest? What have you done?
MC# 15890 until Dec 2016; FMCA #F329677
Cincinnati, OH

Re: Generator diesel/air bleed

Reply #6 –
Peter,
Your engine bleeds fuel back to the fuel tank the whole time it is running.

 Prior to the engine starting, the electric fuel pump starts and will fill the filter and send any fuel it does not need back to the fuel tank through the return line.

If you continue to get air in the fuel system due to a leak in the line the engine will spit, sputter, smoke, and die like you describe. If it runs on a temp. fuel supply I'd look for a fuel line leak.

Pamela & Mike
97 U 320
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Generator diesel/air bleed

Reply #7 –
On our 10K Kubota, I just pre-filled the new filter, and screwed on. No stutters or stumbles. But, the Lord does tend to look after idiots, so take it for what it's worth.
Steve & Ginny Hill
96 U295 36'/Wrangler
Tampa

Re: Generator diesel/air bleed

Reply #8 –
Quote from: Peter & Beth –
Quote from: Dave Katsuki –
Just read in the Isuzu manual that Morris posted, that the Isuzu engine is also designed to automatically bleed any air in the fuel system!
Dave,
I suppose the question is "how much air" before it sputters and shuts off.  My Isuzu ran fine with a field supply of fuel but not with the tank supply.
 
Or, is the "bleed" feature available only once when changing the fuel filter or upon start sequence?  Then, when the engine fires up, air in the lines will not continuously run the engine.  Perhaps this is the reason the engine fires up and only runs for about 5 seconds? ??? ??

I don't know if this answers your question or not.  Our genset has a toggle switch mounted on the control panel on the genset.  Pressing the top portion of the switch cranks the engine to start it. Pressing the bottom portion of the switch apparently causes the fuel pump to run without cranking the engine.

Late last week, I replaced all but one of the hoses on the right hand side of the Isuzu diesel engine due to age cracks on some of them.  After I finished, I was dreading getting the engine primed. So I pressed the bottom portion of the above switch.  I heard a buzzing sound which must have been the fuel pump running.  I held the bottom portion of the switch in for a brief period and then cranked the engine. It did not start so I pressed the bottom portion of the switch again for a longer period of time.  Then I cranked the engine again.  After a few minutes, the engine coughed..then started running rough for a few minutes. Then it smoothed out and ran continuously for around 1 hour.

So it appears pressing the bottom of this switch causes the fuel pump to run until the switch is released or for  some minimum amount of time.
Morris and Janice
1997 U270 36'
 

Re: Generator diesel/air bleed

Reply #9 –
George,
Just fill both filters (remember the other fuel filter under the passenger side outside the quite box) with diesel and you should have no issues.  I changed mine a few months ago and it started right up.

Thanks,
Brad

2000 U320 4000