Genset not getting fuel

[Greg Lepage]

I have a "new to me" used MH with a Kohler 5CKM gasoline genset. It is hard to start and I noticed the in-line fuel filter had been removed. I installed a new inline fuel filter (1/4 inch inline on the hose) and it started but after 3 cranks of 10 seconds each. When it starts, it runs perfectly fine. After two hours of running it on load, I shut it down and it would not restart again. I pulled the new in-line fuel filter and it was almost completely empty of gasoline.

I suspect the fuel line feeding the genset has a crack allowing air in or the device that shuts off that fuel line when the tank is low is defective. Any help with this would be appreciated!

[ccook129]

How much fuel do you have in your unit?Most will not let genset run if tank is close to 1/4.Looks like you have a Winnebago not knowing what model or engine you have,just make sure tank has enough fuel.

[Greg Lepage]

Quote:

Originally Posted by ccook129 How much fuel do you have in your unit?Most will not let genset run if tank is close to 1/4.Looks like you have a Winnebago not knowing what model or engine you have,just make sure tank has enough fuel.

The Winnebago is a 93 33RQ with a 455 chevy gas motor. The fuel level is almost full. I suspect since the prior owner removed the fuel filter that he was having this problem too. I am hoping someone qualified could tell me if the low fuel shut off at the tank could be bad and how I can test it. I can not get under the coach right now due to wet weather to check the fuel line to the genset but will do so when it is not 25 degrees and the ground is dry.

[scgator]

Cause: Defective diaphragm in fuel delivery pump; when sitting idle, it will not allow the pressure side of the pump to "hold" thus allowing the fuel to gravitate back to the tank as the "head" pressure drops.
Cure: Replace the fuel delivery pump.

A fuel delivery pump can produce sufficient output pressure when running, and still "leak down" its head pressure when idle. The fact that the genset will start after a couple of tries, lets you know you have a pump that will build line pressure, but not retain it when idle. If you had a leak or open line somewhere.........when pumping you would find out in a hurry, either in fumes or gas leaking everywhere.

[Greg Lepage]

Quote:

Originally Posted by scgator Cause: Defective diaphragm in fuel delivery pump; when sitting idle, it will not allow the pressure side of the pump to "hold" thus allowing the fuel to gravitate back to the tank as the "head" pressure drops. Cure: Replace the fuel delivery pump. A fuel delivery pump can produce sufficient output pressure when running, and still "leak down" its head pressure when idle. The fact that the genset will start after a couple of tries, lets you know you have a pump that will build line pressure, but not retain it when idle. If you had a leak or open line somewhere.........when pumping you would find out in a hurry, either in fumes or gas leaking everywhere.

Thank YOU for the reply Scgator! I assume the fuel delivery pump is tank mounted and also feeds the motor when it is running (same unit). Although the motor seems to run fine, it sure sounds like my fuel pump is going bad in your description. I am driving 700 miles on Feb 25th so I should have it replaced prior to be safe. Sound correct? Again, thanks your reply makes a lot of sense. I did pull the pump off the generator and test it. It pumped like crazy on 12 volts so the fuel drawing back into the tank seems right on mark.

[Gary RVRoamer]

There is no "low fuel" shut-off device. The intake for the generator fuel line is simply set well above the bottom of the tank, so it will suck air before running the tank dry.

A crack or air leak in the fuel line would cause problems when it is running. I think SCGator has the right diagnosis.

[scgator]

In the late 70's I was a Cummins Certified Master Tech; have reman'd 176 Class 8 engines (Tractor Trailer) NT, NTC, 855, V & VT 555 and 903........I am retired now, and don't turn the wrenches anymore, but still have the knowledge. The last Time I took Cert-Test, I finished second in the State of Georgia.

In my "Better Days" I would do two complete engine inframe overhauls in a 40 hour week, every week; this included all the machine work, crankshaft work, assembly and runtime. Oh, how we long for the good old days.................

[scgator]

Hey.....Gary RVroamer..........you're in Ocala, I grew up in Gainesville GO GATORS !!!

[LVJ58]

For whatever it's worth, had a similar problem last year with our Onan 5500, turned out the fuel supply line had cracks in it near where it connected to the fuel tank. Had to drop the tank and had the entire fuel line replaced.

Hope you can fix yours with just replacing the fuel pump.

[Greg Lepage]

Quote:

Originally Posted by scgator Cause: Defective diaphragm in fuel delivery pump; when sitting idle, it will not allow the pressure side of the pump to "hold" thus allowing the fuel to gravitate back to the tank as the "head" pressure drops. Cure: Replace the fuel delivery pump. A fuel delivery pump can produce sufficient output pressure when running, and still "leak down" its head pressure when idle. The fact that the genset will start after a couple of tries, lets you know you have a pump that will build line pressure, but not retain it when idle. If you had a leak or open line somewhere.........when pumping you would find out in a hurry, either in fumes or gas leaking everywhere.

After reading and thinking....I believe I understand about the fuel delivery pump problem you mentioned. The pump is on the genset. I confused it with the fuel pump on the RV tank that supplies the RV motor and over complicated everything. My local RV tech told me the fuel hose to my generator may have a crack or the fuel pump on the generator is bad. As Scgator said, electric pump on the genset (fuel delivery pump) is not holding the head pressure or vacuum and it allows the fuel to siphon back to the tank. If you can, please let me know if I am on track. Thanks again for your help! The iRV2 web forum is the best in the world. No doubt! I have learned so much.

[Iron Man]

Quote:

Originally Posted by Greg Lepage After reading and thinking....I believe I understand about the fuel delivery pump problem you mentioned. The pump is on the genset. I confused it with the fuel pump on the RV tank that supplies the RV motor and over complicated everything. My local RV tech told me the fuel hose to my generator may have a crack or the fuel pump on the generator is bad. As Scgator said, electric pump on the genset (fuel delivery pump) is not holding the head pressure or vacuum and it allows the fuel to siphon back to the tank. If you can, please let me know if I am on track. Thanks again for your help! The iRV2 web forum is the best in the world. No doubt! I have learned so much.

A crack or split in the fuel line will give same symptoms as a bad fuel pump ie. loose of pressure. Get some fuel line and a gas can and hook the generator up. If problem goes away you know the cause. If problem persist then it is a pump issue.

[Greg Lepage]

Quote:

Originally Posted by Iron Man A crack or split in the fuel line will give same symptoms as a bad fuel pump ie. loose of pressure. Get some fuel line and a gas can and hook the generator up. If problem goes away you know the cause. If problem persist then it is a pump issue.

I used the fuel tank from my boat and after the usual hard starting the motor ran. After shutting it down it would not restart. After removing the fuel hose I realized there was no gas in that line either. Time to buy a fuel pump. Thanks to you all for the replies. I love iRV2.

[Iron Man]

Quote:

Originally Posted by Greg Lepage I used the fuel tank from my boat and after the usual hard starting the motor ran. After shutting it down it would not restart. After removing the fuel hose I realized there was no gas in that line either. Time to buy a fuel pump. Thanks to you all for the replies. I love iRV2.

I like to eliminate all issues before I buy parts. Seems that the fuel pump is the issue.

[wcombs34]

I had the same trouble I have a 02 Bounder, what I found was a crack in the fuel line that feeds the Gen cut the section out and replaced it solved the problem, good luck. wcombs34.