ronboc - extending generator pickup tube

[Sixpack98]

I read you post on extending the generator pickup tube and curious if it was a success. If it was successful can you provide a little detail on how much longer you made the tube and an estimate of how much it helped. My generator cuts out at about 1/2 tank and I find myself making a fuel stop just to keep the generator running. Way too hot in Texas and the dash air can't keep up. I think I recall you purchased a replacement tube but I can't remember if it was from Monaco or from another source. I briefly looked at the tank but did not disassemble anything but curious if maybe adding a short piece of other tubing would work as well. Securely attaching the extension tubing may be an issue as well.

thank,
mark

[Sixpack98]

I read you post on extending the generator pickup tube and curious if it was a success. If it was successful can you provide a little detail on how much longer you made the tube and an estimate of how much it helped. My generator cuts out at about 1/2 tank and I find myself making a fuel stop just to keep the generator running. Way too hot in Texas and the dash air can't keep up. I think I recall you purchased a replacement tube but I can't remember if it was from Monaco or from another source. I briefly looked at the tank but did not disassemble anything but curious if maybe adding a short piece of other tubing would work as well. Securely attaching the extension tubing may be an issue as well.

thank,
mark

[psc907]

Until ronboc answers, check out these posts.

[Sixpack98]

Thanks for the post locations. I read them some time back and curious if his mod was successful.

[Sixpack98]

psc,
One of the posts that you referenced answered some of my questions. My search prior to my post did not display that post. Thanks for info, I appreciate it.

[ronboc]

Hi Mark/sixpack98 –

Yes, the generator pickup-tube extension project was a success for me, in fact a RESOUNDING success! Like you, I did not want the equivalent of a 50-55 gallon tank – especially in the summer! Drove me nuts to have to stop more times for fuel than to go potty (but that's another story altogether ). Now I can go til my bladder is the limiting-factor (and solving that issue that is DEFINITELY a separate topic!)

Now, before I go any further with this discussion, you have to realize this is purely a theoretical discussion on how someone else ˜could' do it... as I would feel really bad if I got a call in the middle of the night from someone dry-camping in the middle of nowhere and they ran the tank down to where the engine was starved for fuel too. OK?

Now that we got that over with, here's how it goes. Opening the driver-side big fuel compartment door (and this is assuming you have a newer Diplomat/Endeavor, or equivalent), there are several fuel hoses attached to the big square-shaped tank. The biggest one is for the fuel supply, there's another one that simply coils up and over and around for the tank-vent, and two more smaller ones. The rear-most hose-connection (ie, to the right as you look in) is probably for the generator (I say probably, as I don't know for sure if there are variants between models or years – but I doubt it).
Anyways, to be 100% sure, CAREFULLY remove/spread the clip and then pull off the hose. Now prime/run the generator for a while and if you picked the right hose, it will soon start sucking air. If not, you obviously picked the wrong hose. Simply try another one, after re-connecting the one(s) you just took off.

Once that's solved, it's a simple matter of talking to Monaco Parts and purchasing a new generator pickup-tube for your coach. They seem to know exactly what you're asking-about, so I doubt it's a new concept for them. I'm sorry but I don't have the exact part-number handy, but they certainly can get it for you quickly. As I recall, it was about $10. It comes full-length.

Here's where the gambling-part comes in. Do you want to be conservative and be sure to have enough fuel to make it to a service-station, or do you want to take fate into your own hands and diligently monitor the fuel-level at all times? Remember, these coaches are pretty-tough to push to the nearest fuel-stop if you guess/calculate wrong!

After you've decided that, it's fairly simple to cut the new tube to the appropriate length. I'd recommend putting the new tube up against the side of the tank, and cutting it a bit shorter than the bottom, that way you're more certain that you don't suck up any crud that may have settled to the bottom. I'd also recommend cutting it at a diagonal (similar to the one you removed) to be sure you don't actually stick it to the bottom.

Then, just carefully re-install all hoses, etc, and enjoy the generator for the next couple-hundred miles.

I've heard of others extending the existing tube, but the idea of it potentially breaking-loose in the tank bothered me to much to try.

I hope you get as many smiles out of doing this project as I have!
Ron

[Sixpack98]

I'm Smiling now. Great post and thank you for taking the time to provide the fantastic detail. We are about to leave on a 3500 mile trip, mostly in the southwest and a generator that wont crap out would be great.

THANKS

[Sixpack98]

Ron,
Wanted to follow up with you. Our coach is the same year as yours but different floor plan. The generator pick-up was where you described and I have ordered a fuel pick-up tube from Monaco. I was also worried that some sort of extension could work itself loose. I'm either going to trim it to about an inch from the bottom or remove and measure the engine pick-up and trim the generator pick-up to be about 2" or so above the engine pick-up. I seem to recall that the tank is about 18" tall so the generator should shut off with about 10 gallons (5 gallons per inch) left for the engine. What length did you end up with? Also, how stiff is the generator tube? I wonder if it moves around when fuel sloshes around in the tank aggregating the problem. I would imagine the main fuel pick-up has a bigger diameter and probably stiffer and less prone to movement.

Thanks for all your help.
mark

[ronboc]

Hi Mark -

Glad I could be of help. be interested to hear the results of your project.

As to how far I cut my gen-tube, let's just say I want to get my money's worth out of that big tank of fuel (it's cut about the same as the engine-tube).

Hadn't considered the 'slosh-factor' but I think the tubes are stiff enough that any movement would be transient. And yes, the engine-tube is larger and stiffer. Not sure how scientific one could become in determining the exact amount left in the tank based on specific measurements, what with acceleration/de-celleration, left/right turns, crowned roads, etc. You're either gonna run out some day - or you're not.

HTH,
Ron

[Sixpack98]

Living on the wild side there Ron, I like your style. What the heck, you can always carry a 5 gal can. Might just get you to the next exit or not.

[Letsgoagain]

Ronboc,
Got a question for you on the pick up tube. Is it threaded into the tank? Did you use some kind of thread sealant or teflon tape when you went back in with the new tube?
I've ordered a new tube for my particular model motorhome and will be making this mod as soon as it arrives.
Letsgoagain

[Sixpack98]

Letsgoagain,
The dip tube does screw into the top of the fuel tank. You will need a 7/8" wrench but I think an adjustable wrench would work as well. I came out pretty easy. The existing tube had sealant that could probably be reused. I bought some Permatex thread sealant at a local parts store. I read somewhere that teflon tape was not advised with diesel. Don't really understand why. You dip tube may be brass and not nylon and that could make it fun to both remove and install the new one.
On our '06 Endeavor the generator tube is the last on the right (most rearward). You can verify on your coach by removing fitting and putting your finger over the hole to feel for suction. Be prepared for the generator to shut down, it will happen and you will need to prime the generator. I also think the generator is very susceptible to any interruption of fuel delivery. After I restarted the engine I pulled the fuel line off for about a second and the generator shut down a few seconds later. I did this 3 times with the same results. I am convinced that fuel sloshing briefly interrupts the fuel flow and the generator thinks it is out of fuel. I think the lift pump on the main engine dampens out intermittent fuel interruptions.
I ordered a tube from Monaco (on backorder) and am going to make it the same length as the main fuel tube. If you dry camp a lot you might also starve the engine as well as the generator.
I'm going to contact Onan and see what their resoponse is. I gotta think someone has complained.

mark

[Letsgoagain]

Sixpack98,
The Permatex is a good idea. Thanks for that suggestion.
I did a little looking around today to scope out the generator fuel supply line. I crawled underneath and on the back of the generator are two fuel lines with each respectively marked fuel return and fuel supply. Couldn't trace each individual one back to the tank but I could discern where the two came in from the front. My year motorhome has the generator fuel supply line in the tank at a different location then your year. For anyone with a 04 HR Ambassador its to the right as you look at it but not the most aft one. There is another larger one more to the back which I assume is the main engine fuel supply. The one you want for the generator is just to the left of that.
Since my new tube didn't come on the UPS truck today I will follow up and verify that it is that tube but I'm pretty certain its the one.
Looks like this will be fairly easy change out and a good modification. Sure don't know why Monaco\HR can't do this to begin with but I guess they're afraid we can't make a rational decision on when fuel is getting low. I know I'll be glad to eliminate the irritation of the generator stalling just below a half tank.
Thanks for your reply and the information.
Letsgoagain

[ronboc]

No teflon, eh? NOW you tell me, Sixpack98! Yeah, the gen does seem to be very particular about fuel-flow. It'd die and take forever to re-prime before I did the tube-mod. Also found out that, unlike a gas-engine, the prime-position on the start-switch is a good thing (I envisioned flooding it, but it just circulates fuel around the lines and the extra goes back to the tank).
Yes, some of the older ones were brass, and a lot tougher to get out/in because they were taller than the space-available underneath. One person had the idea of lifting the tube as far as he could and then cutting the tube and soldering-on the extension at mid-point (a wonderful idea - I'd have never thought of doing it that-a-way!). Diesel does not have as low of a flashpoint as gas, but I still didn't like the idea of soldering right over the tank.
Be interested to hear what Onan has to say. Why ya gonna call them, tho?

You're right, Letsgoagain, the easiest way to find out which tube is which (Monaco Tech Support did 'hint' to me when I was working on the project that all fuel-tubes may not be in the same locations!) is to pull a small one and try to start the gen. And yes, Monaco is trying to 'help' us by making the tube shorter, gotta love 'em for it.



BTW, since I feel responsible for having started this idea of extending the gen-set tubes on our coaches, please be advised that I will be happy come to your remote site with a can of fuel if the unthinkable happens, but it will cost you dearly! Please don't cut the tube too long.


If the tube is backordered from Monaco, have you Googled the OEM for it?