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Fuel Pump Problem

Simon C

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Jul 1, 2015
Messages
699
Location
Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
Isuzu 4LE1NYGV-03 12000Hours
This is a 2017 Generator 25 Kilowatt. It starts up good and runs smooth. Looking for a procedure to adjust the fuel pump for correct frequency.
It holds a load at around 60 frequency, but as you drop off loads it goes up and up until over 63 frequency, shutting down on overspeed frequency.
Not sure if governor needs to be rebuilt, or is it just droop adjustment and other stuff. Have not personally taken one of these governors apart.
Any advice appreciated.
Simon C
 

Shimmy1

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Joined
Aug 14, 2014
Messages
4,448
Location
North Dakota
Isuzu 4LE1NYGV-03 12000Hours
This is a 2017 Generator 25 Kilowatt. It starts up good and runs smooth. Looking for a procedure to adjust the fuel pump for correct frequency.
It holds a load at around 60 frequency, but as you drop off loads it goes up and up until over 63 frequency, shutting down on overspeed frequency.
Not sure if governor needs to be rebuilt, or is it just droop adjustment and other stuff. Have not personally taken one of these governors apart.
Any advice appreciated.
Simon C
Does it have a mechanical fuel pump? What rpm does it hold with no load when you first start it? As in, is it fine before you load it, and then can't slow down when the load is removed?
 

Simon C

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Jul 1, 2015
Messages
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Location
Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
It was adjusted to 61 frequency before loading. Ran at around 59.8 or so with load. The problem is when I pull the load off. Will run fine with load for an hour or more. It is mechanical fuel pump with individual pump units.
Any advice.
Simon C
 

Shimmy1

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Joined
Aug 14, 2014
Messages
4,448
Location
North Dakota
It was adjusted to 61 frequency before loading. Ran at around 59.8 or so with load. The problem is when I pull the load off. Will run fine with load for an hour or more. It is mechanical fuel pump with individual pump units.
Any advice.
Simon C
Maybe try setting it to 59 Hz. From what I've read, most electrical stuff will run just fine at 58-60, but over 60 is when things get wonky. Maybe Birken will have something to say about this.
 

Simon C

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Messages
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Location
Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
I did try turning the frequency down to 58.5, it was working good . Once load was dropped it went down on overspeed frequency. Not sure if fuel rack is sticky, or some other adjustment might fix it.
Simon C
 

Shimmy1

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Joined
Aug 14, 2014
Messages
4,448
Location
North Dakota
I did try turning the frequency down to 58.5, it was working good . Once load was dropped it went down on overspeed frequency. Not sure if fuel rack is sticky, or some other adjustment might fix it.
Simon C
How long since last service? Oil dirty? Might try slowly pulling the load.
 

MarshallPowerGen

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Joined
Nov 26, 2017
Messages
483
Location
Northwestern USA
Occupation
Generator Technician & Equipment Mechanic
What make is it in (MQ, Wacker, etc) and what controller does it have? It could be something simple like stability setting, or could be (likely) a fueling issue. Curious on the controller to see if you can set the over freq higher to give you a wider window to diagnose it still running.
 

Simon C

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699
Location
Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
It is on a Generac Generator. Will post a picture of pump later today as I am not there. The over Frequency setting is currently set at 115%. The valves have never been set on this unit, as the company just got it. Maybe there is too much fuel being dumped in, but it does burn clean with no fuel smell in the air. Trying to get information on if stability setting can be adjusted. Will get controller type tomorrow MarshallPowerGE.
Simon C
 

Simon C

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Jul 1, 2015
Messages
699
Location
Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
Here is a picture of the Governor control linkage.
Will get a full picture tomorrow, along with controller picture for those who might of worked on one.
Simon C
 

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  • Isuzu 4LE1 Governor Control.jpg
    Isuzu 4LE1 Governor Control.jpg
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Simon C

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Jul 1, 2015
Messages
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Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
The bolt looks untouched but I adjusted it a few times. Tried setting unloaded RPM at 59 and when dropping the load afterwards it was still climbing to shutdown point. Am going to try again tomorrow.
The adjustment screw works well. but the problem remained. Think maybe this unit was run a long time with no load. It shot out big chunks of carbon on the first run with load. Maybe something is gummed up. Will keep you posted.
Simon C
 

thepumpguysc

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Mar 18, 2010
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7,705
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Sunny South Carolina
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Master Inj.Pump rebuilder
The way we did the Stanadyne/RoosaMaster is:
LOAD IT.. adjust to 60hz with the droop screw..(gov spring)
UNLOAD IT and watch the rpm, it should climb no higher than either 8-10% or spec for the engine your working on.. and adj THAT w the screw on the throttle..
It looks like there’s a cover to the left of the long screw.. could that be hiding the spring adjuster.??
WHAT is the lever hitting to the RIGHT of the long screw.??
 

Simon C

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Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
So was mislead by operators manual, and specification sheet for machine. Found tag on top of valve cover and unit is a 4LE2-622683
Ran unit couple hours on Friday, and this is what I have observed. The engine was about 50 degrees Fahrenheit on start up and blue smoked and unburn't fuel out of exhaust for 1 minute until I started to put light load to it. As load increased to 50 percent, I had to keep adjusting speed on governor to stay above the bottom shutdown speed (58 Hertz). Of course there is no smoke once up to temperature. At 58.4 frequency or so it did shut down on frequency alert. Ran for more than 1 hour at 59.3 frequency and held load well. However when I dropped the load one breaker at a time the frequency increased until it shut down at 63 frequency.
My thoughts are that the injectors are done at 12000HRS. That was why it fueled so poorly on start up and smelled bad fuel out exhaust along with oil off of cylinder walls. When you drop the load the governor does not pull back the fuel enough, and since I had to increase the vertical down screw on the governor to maintain 59.3 frequency, it then wants to settle down around 63 which is 5 second shut down. The warning light was on the full time of test as it comes on about 0.5 off of nominal 60 frequency.
This unit has not had valves done either from what we can see. So plan to do valves and change injectors to clean up the burn.
In answer to your question( the pumpguysc ) the long vertical down screw turns the big lever. Is that what you would call the droop screw? Behind that lever is a small lever that if you turn it left will shut down the engine.
But also touching the big lever is a small horizontal adjustable screw and nut that is not sure its purpose.
Maybe some kind of buffer screw.
Behind the steel plate is the only way to get at that screw. ( Horizontal screw )
There is hiding behind the steel plate that has to be ground off from what it looks is another screw that faces inward into the block with a jam nut also. Maybe it comes in contact with the fuel rack?
The controller inside is a IntellLite MRS 19HE to answer your question MarshallPowerGen.
Injectors and gasket to adjust valves is $1600 Canadian from Isuzu dealer.
Would probably be a good start, and maybe needs some governor work also. Will need to get a manual eventually, or before I dig into the governor. Company got unit cheap at Auction. Not sure what they will do. Any thoughts on this update.
Simon C
 

thepumpguysc

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Mar 18, 2010
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7,705
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Sunny South Carolina
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Master Inj.Pump rebuilder
I think getting the injectors done is a fantastic idea to start..
There’s no telling what symptoms new injectors will solve..
But it’s a good idea before jumping into the pump adjustment..
Let us know how it works out.
 

Simon C

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Jul 1, 2015
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699
Location
Rocky Mountain House , AB., Canada
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Heavy Equipment Mechanic
So pulled the injectors out of number 1&2 with no problem. Injector 3 took about 300 shots with a hammer against vice grips for it to finally come out. Number 4 was so seized the injector split in 2 at the screwed in joint., so pulled the springs out and cut the fuel connection part of the injector off with a zip disc. Then screwed it back together and tried another 100 shots with penetrating oil in the bore for weekend. No go so had to pull the head off.
Made a punch out of a 1/4 L9 bolt and was able to pound out the injector from the piston side with about 30 shots. It was badly seized but is out. Just got the new injectors at days end. Next week job now.
Cylinders were in good shape with cross hatch still visible.
Will keep you posted.
Simon C
 
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