Generator Fuel Line Replacement

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Generator Fuel Line Replacement

November 11, 2019, 11:27:42 am

Does anyone know how many feet and the size of fuel hose needed for the generator supply and return hoses? Any tips on how to replace them?

The previously owner told me he never used the generator as he was always in a place with shore power, so before departing from California I made an appointment at the local Powertech service center to have it serviced. Before service, they wanted to ensure it would run. After cranking it several times without success, the tech gets a more experienced person who told him to pull the fuel line and run the pre-heat to confirm it was getting fuel. Lots of air in the lines, so he ran it until a steady stream of fuel.

Afterwards, started right up, but died a few minutes later. Checked again, and lots of air, so he recommend replacing the fuel lines which is consistent with many of the posts I have read on ForeForum. He advised against serving it since the oil was very clean and appeared the generator had not been run since it was serviced.

I would prefer to tackle replacing the fuel hoses myself. Does not seem like it is an extremely difficult job. Appreciate any advise.

Thanks

Re: Generator Fuel Line Replacement

Reply #1 – November 11, 2019, 11:45:24 am

Do you have the front or side generator? The side generator supply line can be changed out in 30 minutes WITHOUT pulling the generator out on it's slides. The old line snakes around the other lines and makes it really hard if you attach the new line to the end of the old line. Buy a 25 foot roll as you will save quite a bit over trying to estimate how many feet it will take and buying at a parts store. Don't use the old one to feed in the new one. Use something like a long straight steel brake line and with the tank side compartment door open so you can see light at the other end, you can feed the new line through the hole and then grab it on the far side. Our fittings were two different sizes at each end so had to push a little harder at one end. Use of a Crow's Foot makes life a lot easier if your tank is like ours. I only replaced the supply line on ours as the return line was not damp. Nice to do both though. Use wrap around clamps to avoid air leaks. Leave enough extra hose so you can slide the generator out on it's slides to change oil, etc. Don't watch the other Foretravel YouTube video on changing the hose. It's not correct.

Unless you use the electric pump to bleed the system with the T handled valve open, you may not be able to start the generator. See my post from a couple of days ago with a photo of the valve. If you have the valve or open a fitting a half turn, you don't have to pre-fill the secondary filter. Even if you bleed the system, you still may have to crack an injector pipe at the injector while cranking the engine to get it to start. It's a super easy job once you have done it and know the tricks. PM with any questions.

Pierce

Re: Generator Fuel Line Replacement

Reply #2 – November 11, 2019, 02:43:12 pm

Quote from: Pierce & Gaylie Stewart – November 11, 2019, 11:45:24 am

Do you have the front or side generator?

Pierce

Pierce,
Thank you for the details and suggestions. Ours is a front mount, but will give it a try this weekend.

Re: Generator Fuel Line Replacement

Reply #3 – November 11, 2019, 04:39:59 pm

Replacing part of the hose can take care of air leaks if the crack is the hose that is up front from being flexed. Use a pair of barb connectors to join new with old. Lots of access under coach above front axle.

If this quick fix takes eliminates air entry, there is no need to fiddle with the fuel tank end of the hose.

Re: Generator Fuel Line Replacement

Reply #4 – November 11, 2019, 05:09:57 pm

There's plenty of posts on the forum about replacing a fuel lines in the U320. Crane man as well as myself have made posts on it in the last year, just do a search. I use crane man's measurements when I replace mine and found that I had a fair amount of hose left over. I think 25 ft or so is what I use to get to and from the generator. I replaced all my fuel hose at the same time pulling the tank out I put a fair amount of pictures on my posting so you could see how it was done. Good luck.

Re: Generator Fuel Line Replacement

Reply #5 – November 11, 2019, 05:34:35 pm

Hoping you are also planning to replace the ones to the big engine at the same time?

Once one set develops leaks, it's generally time to do them all.

Re: Generator Fuel Line Replacement

Reply #6 – November 11, 2019, 05:41:13 pm

Quote from: Bob and Julie – November 11, 2019, 05:09:57 pm

There's plenty of posts on the forum about replacing a fuel lines in the U320. Crane man as well as myself have made posts on it in the last year, just do a search. I use crane man's measurements when I replace mine and found that I had a fair amount of hose left over. I think 25 ft or so is what I use to get to and from the generator. I replaced all my fuel hose at the same time pulling the tank out I put a fair amount of pictures on my posting so you could see how it was done. Good luck.

Fuel hose replacement post

Re: Generator Fuel Line Replacement

Reply #7 – November 18, 2019, 08:14:21 am

Had a little time to work on the generator this weekend. After examining the fuel hose, it looked like it has been recently replaced as it appeared new and felt supple, but did notice the clamp was loose. Tightened it and the generator ran for about 20 minutes before stopping. Starting thinking it might be the temp or oil pressure sensors.

As a confirmation it was getting fuel, I temporarily replaced the short fuel line from the filter to the injector pump with clear tubing. Generator ran again for about 20 minutes and started missing some, then quit. It was easy to see lots of bubbles in the clear tubing, so it confirmed the pump was pulling in air.

Crawled under the coach and just after the fuel line went passed through the generator bay wall, it was spliced together. I purchased fuel hose, but it has not arrive yet. I purchased Parker Superflex 39708.

Re: Generator Fuel Line Replacement

Reply #8 – November 18, 2019, 10:38:26 pm

A loose water pump belt slowly causes overheating

Re: Generator Fuel Line Replacement

Reply #9 – November 18, 2019, 11:27:42 pm

Quote from: Caflashbob – November 18, 2019, 10:38:26 pm

A loose water pump belt slowly causes overheating

I will check the belt. Thanks for that info.

The new fuel line I ordered arrived and spent some time running it tonight only to find I ordered the wrong size line. I ordered 3/8" line since that was how the existing line was marked. A PO spliced in about 4 feet of new line that was 3/8". The barb where it connects at the generator is 5/16 which is likely the source where it is drawing in air. Since I have already purchased and pulled in one hose, I think I will just replace the barb with a 3/8 barb.

Re: Generator Fuel Line Replacement

Reply #10 – November 20, 2019, 06:38:16 am

I believe the air in fuel issue is resolved. I replaced the short section of supply line with 5/16 hose and after bleeding out all of the air, the generator then ran for 20 or 30 minutes (did not time it) and shut down. I still have the clear tubing between the fuel filter and injector pump and am not seeing any air, so suspecting it might be shutting down on over temp. Let is set for 30 minutes and it restarted and ran again for a few minutes before shutting down. Again, I did not see any bubbles in the fuel.

Model is Power Tech PTS MH 10 with a Kubota engine. The radiator is located in the bay under the driver's seat. Am I correct in assuming the electric fan should come on to blow air over that radiator? I cannot hear anything, so if it is supposed to be running, that might be the problem.

To change the belt on the generator, do I pull it out and remove the shroud?

Open to any suggestion on how to confirm it is over temp or do other diagnostics.

Re: Generator Fuel Line Replacement

Reply #11 – November 20, 2019, 07:26:31 am

Quote from: DayDreamer – November 20, 2019, 06:38:16 am

1. The radiator is located in the bay under the driver's seat.
1a. Am I correct in assuming the electric fan should come on to blow air over that radiator?
1b. I cannot hear anything, so if it is supposed to be running, that might be the problem.
2. To change the belt on the generator, do I pull it out
2a. and remove the shroud?

DayD,

1a. Yes
1b. Yes that is about the amount of time it takes to go into over heat from a cold start.

With what you have said the generator must be making power while it is running if that is the case here is some things to look at.

The fan power comes directly off the generator breakers so if the generator is making power the fan should be running. There is no thermostat that controls the remote fan. Now with that being said check the back side of the breakers on the generator control box for a loose wire. There is a junction box just above the remote fan, so remove the cover and make sure one of the wire nuts have not came loose. While there do a quick run again and see if you have power here. You may also have a motor capacitor that has failed. If that is the case you will need to remove and replace dead capacitor. (it is hid behind the motor so the whole fan/motor assembly has to come out) Check fan to see of it spins freely, one of the bearings could have locked up. Lastly and the least likely the motor may have give up the ghost.

2. Yes
2a. on some generators yes. Yours looks like it can just come loose at the bottom and the belt will sneak out from around the pully.

Mike

Re: Generator Fuel Line Replacement

Reply #12 – December 01, 2019, 09:14:49 am

I think my generator issues are resolved.. Original issue was definitely air in the fuel lines. Second issue was generator fan was not running because I did not have the unmarked toggle switch in the on position. Has been running for over an hour now, so I think that issue has been resolved. Many thanks to all for your comments.

Re: Generator Fuel Line Replacement

Reply #13 – December 01, 2019, 01:48:53 pm

DayDreamer,

Be aware that the "toggle switch" is actually a circuit breaker. Over time it can become weak and trip easily, shutting down the fan. I had to replace my circuit breaker several years ago.

Re: Generator Fuel Line Replacement

Reply #14 – December 01, 2019, 02:02:40 pm

Quote from: Jan & Richard – December 01, 2019, 01:48:53 pm

DayDreamer,

Be aware that the "toggle switch" is actually a circuit breaker. Over time it can become weak and trip easily, shutting down the fan. I had to replace my circuit breaker several years ago.

Definitely good to know. Any chance you have a part number or is there a specific name I should use when I search for the switch/breaker?

Re: Generator Fuel Line Replacement

Reply #15 – December 01, 2019, 02:10:07 pm

Sorry, no part numbers. It has been a long time ago. As I recall I bought the part from Power Tech.

Re: Generator Fuel Line Replacement

Reply #16 – December 01, 2019, 03:18:48 pm

Quote from: DayDreamer – December 01, 2019, 02:02:40 pm

Definitely good to know. Any chance you have a part number or is there a specific name I should use when I search for the switch/breaker?

Chris posted these p/n's several years ago:
Question wiring blower breaker on generator

Good Luck, Dave A

Re: Generator Fuel Line Replacement

Reply #17 – December 04, 2019, 11:53:32 am

Quote from: Pamela & Mike – November 20, 2019, 07:26:31 am

DayD,

There is a junction box just above the remote fan, so remove the cover and make sure one of the wire nuts have not came loose. While there do a quick run again and see if you have power here.
Mike

In the for what it is worth category, I opened the junction box above the remote fan to check the connections and confirm power. The twist on wire connectors (ie. wire nuts) are too big for the two wires which appear to be 14g wires so the connections were tenuous at best. When I removed the connectors, the two wires were not twisted together as they should have been. I replaced with appropriate size.

Re: Generator Fuel Line Replacement

Reply #18 – December 04, 2019, 11:55:52 am

Quote from: DayDreamer – December 04, 2019, 11:53:32 am

In the for what it is worth category, I opened the junction box above the remote fan to check the connections and confirm power. The twist on wire connectors (ie. wire nuts) are too big for the two wires which appear to be 14g wires so the connections were tenuous at best. When I removed the connectors, the two wires were not twisted together as they should have been. I replaced with appropriate size.

The wires entering a wire nut are not supposed to be twisted when you insert them. The old school of twisting the wires and using friction tape does not apply to using a wire nut.

Re: Generator Fuel Line Replacement

Reply #19 – December 04, 2019, 12:32:32 pm

Quote from: craneman – December 04, 2019, 11:55:52 am

The wires entering a wire nut are not supposed to be twisted when you insert them. The old school of twisting the wires and using friction tape does not apply to using a wire nut.

I agree about not twisting them before inserting, but should the wire nut not twist them together? Typically when I remove a connector, the wires have been twisted, even though I did not twist them together before I inserted them. I am not an electrician, but have replaced a lot of wire at the house. After installing the connector, I give the wires a tug to ensure they are mechanically connected. I think the only thing holding the original connector on was the electric tape.

Re: Generator Fuel Line Replacement

Reply #20 – December 04, 2019, 12:39:53 pm

If the wire nut was too large it would not twist them correctly.

Re: Generator Fuel Line Replacement

Reply #21 – December 04, 2019, 03:32:13 pm

Quote from: DayDreamer – December 04, 2019, 11:53:32 am

(ie. wire nuts) are too big for the two wires which appear to be 14g wires so the connections were tenuous at best.

DayD,

I have found several like that. On one coach it had started to heat up due to bad connection. This is the reason I suggested you look there while in the area. That is good PM work.

Mike

Re: Generator Fuel Line Replacement

Reply #22 – December 05, 2019, 09:39:52 am

Rule of thumb in a boat is to never use a wire nut on a electrical connection due to its constant movement. I believe that a RV while not exactly the same should benefit from that same idea. I try to never use a wire nut on my RV, and replace those I find when I can.
Poor electrical connections result in heat which can result in a fire.
When possible I use a butt splice connection, followed by marine grade heat shrink tubing with a adhesive lining.
Other times, I solder the connection, then follow with the same heat shrink tubing.
Wire nuts imo, should be left for home use where the home doesn't move much, or at all.

Re: Generator Fuel Line Replacement

Reply #23 – December 05, 2019, 09:52:27 am

Quote from: Bob and Julie – December 05, 2019, 09:39:52 am

Rule of thumb in a boat is to never use a wire nut on a electrical connection due to its constant movement. I believe that a RV while not exactly the same should benefit from that same idea. I try to never use a wire nut on my RV, and replace those I find when I can.
Poor electrical connections result in heat which can result in a fire.
When possible I use a butt splice connection, followed by marine grade heat shrink tubing with a adhesive lining.
Other times, I solder the connection, then follow with the same heat shrink tubing.
Wire nuts imo, should be left for home use where the home doesn't move much, or at all.

Sounds prudent, but do not think I am energetic enough to go that route. Only boat I have ever owned was a small sail boat, so did not have much electrical. Seems like a big concern in a marine environment would be corrosion which I presume the heat shrink tubing would help minimize.

Unfortunately, our house moves way to much as it is built on expansive clay, but not as much as the coach.

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