Hi all,
On the way home on our last trip we ran a bit low on fuel. When we overnighted the genset started a bit hard and stalled a couple of times. i do know that at about a 1/4 tank the fuel supply to the genset is too high for it to run and we may have been to that point.
Since then it will not start. Filled fuel tank and I changed out the fuel filter today and filled the new one before installing. Also have tried bleeding the injector bleed screw but getting no fuel to it.
BTW it's a Kubota based Power Tech 10KW genset. Assuming it's a fuel issue somewhere. Any ideas?
Thanks, Dean
Did you bleed it up where the line enters the engine?
Very good chance it is the fuel pump.
Have you verified that you are getting 12 volts at the fuel pump when the engine is calling for it in the 7 seconds or so before the engine actually starts? If you are getting 12 volts then your fuel pump is non-functional.
Also check to make sure that you don't have a kinked fuel hose in the generator bay and if you have 2 fuel filters, both of them are clean. With a functioning fuel pump, you should be moving a pretty good amount of extra fuel through that engine. Could also be damaged or broken fuel line if you haven't changed them out.
I noticed a big difference by switching to one of the cylindrical facet pumps that some of the other people here have changed to. Engine just sounded completely different with the new pump.
The good news is that you know it has to do with the system not getting fuel which will make your troubleshooting much easier.
Edit: It could also be one of those tiny carburetor filters attached to the fuel pump being clogged.
A couple of weeks after I had my fuel filters changed, a different RV shop tried to start the generator. Said it started and ran for a few seconds, after that, nothing. When the got there, I tried starting it from the generator itself. I noticed on the first attempt pt, it tried to start, but only one or two coughs. I waited a few minutes and tried again. Slightly better. I did this about four times over half an hour. It finally started and has been fine ever since. Must have had air in the line.
Earlier, I ran the tank lower than planned and shut down the generator before it quit, just before. After fueling up, the generator quit after a few seconds. Again it took a second try to get it going. More air.
Yes I did Dave. No fuel at the bleed screw.
I have attempted to start it about 10-12 times. Twice it sputtered a couple times and I thought it would catch but no dice.
Will now be checking fuel pump etc. and see what I find. I still think it's air but you would think the fuel pump would pick it up eventually.
Thanks for the advice guys. Will keep looking.
Dean
Mine did the exact same thing in my 1996 coach on the way to Louisville a year ago. At first I thought it was that I ran the fuel too low. I filled up the tank and it ran again but not long. Ordered a new pump from PowerTech and they shipped it overnight for me. I tried the fuel filters and bleeding to no avail. Replaced the pump and it has worked great ever since.
Take the outlet of the pump off and depress the preheat switch and pump should pump fuel out.
So I just went out and checked again. I can hear and feel the pump working (or trying to) when I hit the preheat switch. Would this still occur if the pump is bad?
As I was feeling around I did find the fuel line on the output side of the pump was wet with fuel just above the clamp. I cut back the bad spot and refit it. Pretty sure it was just a stress crack at the fitting. Seems to be good now.
I found this with a search, is this the replacement pump you guys are referencing?
KUBOTA Generator Fuel Pump (http://www.foreforums.com/index.php?topic=12429.msg64962#msg64962)
Dean
That is one of the good pumps that work.
But before you buy the pump, have you changed the fuel filter that is located between the fuel tank and the back of the generator, raise the coach, crawl under, you will see it, it takes the same filter element that the Aqua Hot uses. This is a very common over looked item that will act just like yours is.
Once you get a good filter and the pump is working, you will need to bleed the entire fuel system from the injection pump thru to the injectors. Just cranking once it is full of air, you will only kill the batteries and/or burn up the starter, easy to bleed the Kubota system.
Just a thought.
Huh, didn't know there is a 2nd filter. None of my manuals/info mentions one. Guess I will have to take a trip under the coach in the morning and look around. Someone also mentioned that the fuel pump has a filter inside of it?
Dean
The filter between rear of generator and the fuel tank is the Racor R12T element.
Beware when removing the filter, fuel might leak out of the filter housing.
Thanks Dave. I am going under to check it out this morning. Wondering if I will need to slide the genset out to get at things. Hoping it's just the prefilter causing the issue and not the fuel lines. From what I have read on search's those are a bear to change.
Dean
Success! ^.^d Dave M was right, there was a Racor R12T filter behind the genset. It had been changed in 2012. Went to Napa and picked up the equivalent and changed it out. Genset still wouldn't run. Took 3 feet of 5/16 fuel line hooked to the inlet side of the pump and into a small jug of fuel, wouldn't start. Filled the line/pump with fuel and tried again, fired right up. Figured fuel lines at that point.
Slid the genset out on the tray and followed all the lines I could see. No sign of leaks or kinks. Put genset back in and reprimed the pump by filling the inlet again. Started right back up and ran for 6 or 7 minutes then died. Repeated this 3 times while bleeding the injector bleed screw. Finally got a big gush of fuel and air, genset started and has been running for 45 minutes.
Happy, happy.
BTW I do have one of the cylindrical pumps and it appears to have been replaced at some point. So the moral of the story is if you run the generator out of fuel, that little pump probably won't prime itself. Too far for it to pull fuel. Put a short hose on it and continue to fill, switch lines, repeat until it catch's fuel and purges the air.
Thanks for the support, Dean
The moral of the story is to not run the diesel fuel tank too low. How about filling up at about 50 to 60 % empty. Other problems with too low is engine, & aqua hot getting air, engine getting hot fuel to burn, turning corners or parking on an angle moving fuel away from pickup tube, etc.
There are a few items one needs to pay attention to (more to the moral story) besides fuel filters, in addition look close to the jumper lines on the injectors, they age, get dry & brittle like any rubber does. Upon close snooping of my genset, I replaced all the fuel lines from the Racor in including the return hoses.
I prefer dependable generator operation instead of hoping it works.
Dean:
Glad you hung in there and found the solution. It is great having an expert like Dave that is willing to help.
Jason
Barry I agree, and we typically run off the top half of the tank only. When I filled up the other day it took 101 gallons, so there was 79 still in the tank. Plenty to be well above the genset pickup unless it's set too high in the tank.
The genset had been acting up at full fuel too so I am 99% certain it was a filter issue. By changing out both filters you put a lot of air in the lines which can be pretty much the same as running it out of fuel.
I guess my point was that that little pump will most likely need priming in order to pull fuel, regardless of how the condition occurred. At least that was my experience.
The Bendix style pump is easily primed (if needed.)
Remove the fittings and fill the assembly.
Early on, fuel pumps were re-buildable.
I repair MEP Onan (mostly) military Gen-sets. They have the Bendix style electric pump.
Unless run over by a lawnmower they are hard to kill. pc
I think we will be surprised how many gallons a fuel tank rated at 180 gal will hold. There is a lot of air space in a tank's rated capacity that will never hold any diesel.
In an analysis I did for a 190 gallon Foretravel diesel fuel tank, there are only 155 usable gallons.
Inside tank size 23.5" tall, 87.875" side to side, 21.25" front to back 43,883 cu in = 190 gallons. Less 2" for top air space = 16 gallons less Less another 2" for extra top air space = 16 gallons less Less 0.375" for engine pickup tube 3/8" off the bottom = less 3 gallons. 190 gallons less 35 gallons = 155 gallons.
Filling 101 gallons on a 145 gallon capacity tank, could mean that tank was 30% full with 44 gallons remaining or 308 gallons to empty. Not bad even allowing for generator which uses a pickup 2-1/2" off the bottom so it should have about 20 gallons more for gen to use.