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Frustrated- No Start Generator – Oh why???
Ok, I have a Kohler 20W genny. Seems like this brand comes up a lot with issues or so it seems. Last year was having issues with the genny shutting down after 20 minutes or so. So I did a oil change, oil filter, fuel filter and air filter. Still had same issue. So I changed out the fuel pump. I bled fuel lines of air and she started right up. Has run perfect for last six months.
Last Friday I started the genny and ran it for 3-4 hours under medium load. Came back to bus and the genny had stopped running. Back to square one- will not start.
I noticed a little bit of fuel just under the fuel pump One of the fuel lines was a little loose. I tighten the fuel light and start to re-bleed the lines of air (assuming if it was leaking it may have been sucking air as well)…
Now I notice no fuel or bubbles at any of the bleed points. No fuel at the injectors.
I put a meter on the pump and it is jumping from 12 down to 10, 9 8 volts etc…
I then put a meter on the possitive and negative connectors that go to pump and try starting.
I am not getting 12 volts to the pump- what can be causing this?
I then by-pass the connecting wires to the pump and attached a battery charger to get 12 volts.
I try starting the genny and work on getting air out of system. Still no fuel appears to be running through lines? I hear the pump spinning.
I am at my last straw on this. I have spent all Summer trying to keep the genny running. I am going to replace the filters on Wednesday. But still need some guidance….
Tully
T
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15 Replies
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Maybe connect another fuel pump of some kind to the line that comes from the fuel tank to your genny pump, this should draw fuel through the filter.
Disonnect the line and attach to the new pump and see if you are getting fuel from the tank through the line.
Any kind of pump you can connect to the fuel line and try to draw fuel through.
Maybe get on the line where it goes into the filter so you can draw straight from the fuel tank.
If that fails try blowing air through the line back towards the tank, careful with the air pressure, then see if you can hear air bubbles in the tank. Maybe line is stopped up.
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What are your thoughts on the fuel pump getting less than 12 volts? Wha could cause this?
Tully
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how much fuel is in the tank,I would want at least 1/2 to verify that is not the problem.
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When the starter is spinning the generator to start it the current draw is high so measuring voltage at the fuel pump when the generator is trying to start is going to show a voltage drop.
What I do not know however is what is normal for a generator that does not have any issues.
There have been times when I have dealt with starting issues and found I was not the only one that has had a bad fuel pump on a 20KW Kohler. I have had to replace the pump so for me to believe your second pump might be bad is not a stretch. Obviously you need to be delivering fuel for the generator to start so after changing filters or having a slow to start generator I have applied 12V to the fuel pump and listened to the sound change until it was obvious the pump was pushing fuel under pressure. That way I knew I had fuel at the injectors. The generator would then start promptly.
The fact the generator had quit after running seems to me to be a clue about the fuel pump. I would crack a fitting and operate the pump to verify it is pumping. I agree with Jack and Buddy. If you suspect the pump, make sure you have ample fuel, but temorarily stick any electric fuel pump in line to see if the generator will run OK. Kohler seems proud of their pumps and they are expensive, but you can get a cheap but functional pump at NAPA for very little money.
I would not try all this without making sure the generator start battery is good. Give it a full charge.
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All good points and to expand on Jack’s comment, most of the buses once you’re 1/4 tank of fuel or under, the gen won’t pick up fuel.
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Genny battery is good, check voltage. Spins genny fast. I have new filters I will install today. I know when I put 12 volts to pump I hear it kick on and hum. So I will take off the inlet hose where fuel enters the pump and put that hose into a fuel can and see if it starts or is sucking in fuel. As well, will pull the outlet side and when turning over engine will see if it is pushing fuel.
Will update-
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I have a full tank of fuel and the oil is at full and anti-freeze is a proper levels.
Tully
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The old adage about giving the engine air and fuel still applies. If you are delivering fuel to the engine and not choking off the air it should start.
I don’t know the required fuel pressure range but that is one thing to verify. I suspect Kohler has the engine tech data on line, or can provide it.
If there is an entry point for air in the fuel system prior to the fuel pump that could ultimately turn out to be the issue if the pump does work. But the fact the generator shut down by itself (not attributable to over temp or low oil pressure) keeps me looking at the fuel pump.
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Just for kicks, check the low coolant level switch if it has one. I had one go bad, and even though coolant wasn’t low, it would cause it to start, not start, shut down. and so on. It would kill power to the fuel solenoid.
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Nick on the other board had a simular problem just pop up . turned out to be a clogged pick up line from tank. Was discovered when he put pressure to the supply line back to the tank–that relieved plug–unknown? Speculation was sludge or a foreign body in main tank that got sucked over end of gen supply inlet. Might never happen again as long as he has coach. I have found things like the foil seals on addative bottles or the plastic orings in fuel tanks often.. Any air leak in a suction situation is fatal.. Bob
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Thanks for all the replies. I got it going. Not really certain how. I pulled off the out-let line on the pump and it was spitting a little fuel when I was cranking it over. I put in a new fuel/water seperator filter. Tightened everything up. Now all of a sudden I was able to get fuel and bubbles at the bleeding points. Re-bled and she fired right up!
What the heck? I am glad it is running but would like to know why? What did I do?
Tully
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You fixed it. Good job!
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Tully,
FWIW my 87 coach had a generator that would start right up if it had been in use within the prior couple of weeks. Since we dry camped often with that coach we were using the generator frequently so it was not an issue trying to get it to start. But if it had been sitting for a month or more it would never start using the start function.
I had no clue why, could not find any issues, but did learn that prior to a trip if I hooked 12V power to the fuel pump and listened as it pressurized the fuel system I could tell when fuel was where it needed to be for the generator to start.
The fuel pump made a rapid clicking sound, and as fuel began flowing and pressurizing the fuel system the fuel pump clicks slowed down to the point where it was a slow click, click, click. The generator would then start right up. So I stopped trying to find what was likely a minute hole or leak in the fuel system and just used my fuel pump pressurization method if the generator had not been run in a long time. It could have been a pin hole admitting air, a bad check valve, or just something internal to the injectors or the engine.
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Jon, on Onan generators we can hold the start swtich in the off position and it will run the fuel pump, doing a good job of priming the generator. I do that after changing fuel filters or if I should run the fuel tank too low and need to prime after fueling up.
Will the Kohler do that?
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Les, I never tried. I have only had an issue with the Kohler when the fuel pump acted up. When I replaced the pump the problems went away and never reappeared.
When I change fuel filters I fill them if I can, or just let it crank. It doesn’t take long to fire up.
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