How long does the generator take to start?

[16ACE27]

Originally Posted by jerber

I have a 2016 Thor outlaw with a 4000 jenny and on the last trip coming home none of the appliances work off the jenny.when we got home and plugged into shore power all the appliances work.Is there some kind of transfer switch that I could reset or does anyone have an idea what to look for?Thanks Jerry

Nothing to reset but there is an Automatic Transfer Switch, generally near/behind your breaker/fuse panel that has a reputation of poor twist-on wire connectors. That is most likely your problem.

[Pete'sMH]

Also, there is a circuit breaker on the side of the generator - not intuitively located - that might be tripped. The generator will start and run normally but it won’t deliver any power.

[Wiley1]

Originally Posted by jerber

I have a 2016 Thor outlaw with a 4000 jenny and on the last trip coming home none of the appliances work off the jenny.when we got home and plugged into shore power all the appliances work.Is there some kind of transfer switch that I could reset or does anyone have an idea what to look for?Thanks Jerry

Yes, somewhere you have an ATS (automatic transfer switch). To find it, follow the shore power cable from where it enters the coach. The first place it goes should be the ATS.

The other cable entering the ATS will come from the Genset.
The output of your ATS will lead to your 120V breaker panel.

When you get inside the ATS, you should be able to read both inputs and the output with a multimeter. Check them under all three conditions: Genset with no shore power, shore power with no genset, and both connected at the same time. As we have been discussing in this thread, when both are running, it is typical for the generator to be given priority. While you're in there, tighten everything, before and after testing.

If you get in there and find no voltage on the generator input, that suggests the problem is in your genset.

If all connections are tight, there are no signs of arcing or sparking, and you have a good voltage on the gen input, you may need to replace the ATS. It might also be possible to change a component or two inside the ATS without purchasing a whole new box.

[Jimbo56]

Originally Posted by groucho4u

I saw a lot of good answers, but I didn't see any about installing a gas shut off valve. Or if it has one, use it every time. My onan 4000 needed service 2 times. Once when I cranked too long, 15 second max? And another when I didn't use the valve. When I don't use the valve, it's hard to start, and now it fires right up.

Where is this “valve”?

[Jimbo56]

We have Onan 4000 with around 150 hours on it. Have serviced it as manual says. Ever since day 1, I have to prime it for 1 full minute. A slow count to 60. Hit start and it fires right up. This is the case even if I ran it for 6 hours while driving, turned it off when got to campground. And started it up next morning. The prime light stays on the entire time I’m holding the switch down. Count to 60. Starts right up. My fuel tank is in rear. Gen is up front in compartment behind propane on drivers side.

[blw2]

Originally Posted by Pete'sMH

Mine rarely starts on the first try no matter how long I prime it first. I’ll usually let it crank for about 10 or 15 seconds after priming then let it sit for another 5-10 seconds and it will then fire immediately upon cranking again. Don’t know why this works but it is very consistent

mine is the same way...especially if it hasn't run in a while.
Shameful really. I've had lawn mowers with Briggs engines to be far more reliable and less finicky!

I'll generally prime for 20-30 seconds
pause for a moment
then let it crank a bit
then I'll prime again for a few seconds
and then most of the time it'll fire up with a few seconds of cranking

Mine has a very long tube run back to the fuel tank.

One thing I've noticed is that when the battery is a bit weak it'll seem like it's cranking fast enough but it'll be much harder to start.
If I'm having trouble with it I'll fire up the chassis engine, pause a bit so the Bird will join the systems...or push the e-start button... then try the genny again. That usually helps.

[16ACE27]

Originally Posted by Jimbo56

Where is this “valve”?

There is not one.

[dkoldman]

I have a question for anyone that has to Prime before the generator will start? Do you have AGS; and if so; does it work? Meaning will it AUTO start by itself.

Why so many have to Prime just baffles me The question or focus may be on why is your genset is out of gas? If you have gone long periods of time that may explain it, but specify how long in between your last start? Could you have gas evaporating somewhere? If so; that could be very dangerous.

My guess is that on average my genset runs at least once every two weeks, but I manage to get 6 or 7 hrs a month. But I never have to Prime; and the genset starts in 3- 5 seconds everytime. Anybody run their genny equivalent to that, and it stills requires Priming?

I realize some may consider it normal to prime everytime, but there is a reason why? Out of gas or recent change of fuel filter are the only variables I know.

[Beau388]

Originally Posted by dkoldman

I have a question for anyone that has to Prime before the generator will start? Do you have AGS; and if so; does it work? Meaning will it AUTO start by itself.

Why so many have to Prime just baffles me The question or focus may be on why is your genset is out of gas? If you have gone long periods of time that may explain it, but specify how long in between your last start? Could you have gas evaporating somewhere? If so; that could be very dangerous.

My guess is that on average my genset runs at least once every two weeks, but I manage to get 6 or 7 hrs a month. But I never have to Prime; and the genset starts in 3- 5 seconds everytime. Anybody run their genny equivalent to that, and it stills requires Priming?

I realize some may consider it normal to prime everytime, but there is a reason why? Out of gas or recent change of fuel filter are the only variables I know.

I don't have a working AGS. If the generator has run within the last couple of days, it does not need to be primed. If it has been longer than a week, it will shutdown during cranking with a over crank fault. It will start on the second cranking after about 5 seconds. It is best to prime for about 30 seconds before starting if it sets in the hot sun for over a week. If it sits for three weeks the a 45 second prime is necessary. The thought is the carb bowl dries out and the gas drains back into the tank so 20 ft away when it sits for too long.

[dkoldman]

Originally Posted by Beau388

I don't have a working AGS. If the generator has run within the last couple of days, it does not need to be primed. If it has been longer than a week, it will shutdown during cranking with a over crank fault. It will start on the second cranking after about 5 seconds. It is best to prime for about 30 seconds before starting if it sets in the hot sun for over a week. If it sits for three weeks the a 45 second prime is necessary. The thought is the carb bowl dries out and the gas drains back into the tank so 20 ft away when it sits for too long.

Thanks, now we are getting somewhere as you have just confirmed that it truly is out of gas condition which is what Onan says. So one that has this issue could run there genset before setting AGS to AUTO Mode and it will work just fine over next several days

Still does not explain why I can go so long without an issue; so I just go outside and measure the distance from my genny's fuel pump to the gas tank. It is 30" compared to what you are saying is 20ft? So maybe that is factor for why I have NEVER had to use the Prime feature? I once went 2 months without using the Genny when it was at a Dealer last year. 3 - 5 secs to start with no prime is all I have experienced tops.

[Beau388]

Originally Posted by dkoldman

Thanks, now we are getting somewhere as you have just confirmed that it truly is out of gas condition which is what Onan says. So one that has this issue could run there genset before setting AGS to AUTO Mode and it will work just fine over next several days

Still does not explain why I can go so long without an issue; so I just go outside and measure the distance from my genny's fuel pump to the gas tank. It is 30" compared to what you are saying is 20ft? So maybe that is factor for why I have NEVER had to use the Prime feature? I once went 2 months without using the Genny when it was at a Dealer last year. 3 - 5 secs to start with no prime is all I have experienced tops.

My generator is just being the left front wheel, well - behind the leveling pump which is behind the left wheel well. It is a 190" wheel base coach with the gas tank pick-up 41 inches behind the rear axle. The coach's parking spot faces almost due west, so it is in the sun 12 hours a day. I have a 50 amp pedestal at the space so no need to run the generator except for exercise or on a trip.

[dkoldman]

Originally Posted by Beau388

My generator is just being the left front wheel, well - behind the leveling pump which is behind the left wheel well. It is a 190" wheel base coach with the gas tank pick-up 41 inches behind the rear axle. The coach's parking spot faces almost due west, so it is in the sun 12 hours a day. I have a 50 amp pedestal at the space so no need to run the generator except for exercise or on a trip.

Wow, I guess I use my generator like some play with a Text Toy . I just get a thrill out making it work in Auto or Quiet time modes. We have 110amp Power Pedestal at home as well; sometimes I disconnect for like two weeks at a time. I just like to play with watching how low the batteries go down with nothing plugged in. When ever I run the genny at home, I try to use the AGS; but not always (80/20). A good example is when we plan a trip or drive, I go put the genny in Auto mode and then disconnect the power, it starts up cool the coach and the fridge; when we finally are packed ready to go 1 or 2 hours later, I can just drive away without having to fool with the shore cord.

Maybe I over do it, but it makes it kind of fun to play with $140,000 sitting in the driveway everyday. We still work; so those precious minutes playing with those AGS buttons makes my day All kidding aside, when we do travel my confidence level on the RV is sky high. I use to think I was getting in over my head buying an RV versus just renting when I need. But I have come to learn my RV it is an Engineering Masterpiece that I just love.

[Beau388]

Originally Posted by dkoldman

Wow, I guess I use my generator like some play with a Text Toy . I just get a thrill out making it work in Auto or Quiet time modes. We have 110amp Power Pedestal at home as well; sometimes I disconnect for like two weeks at a time. I just like to play with watching how low the batteries go down with nothing plugged in. When ever I run the genny at home, I try to use the AGS; but not always (80/20). A good example is when we plan a trip or drive, I go put the genny in Auto mode and then disconnect the power, it starts up cool the coach and the fridge; when we finally are packed ready to go 1 or 2 hours later, I can just drive away without having to fool with the shore cord.

Maybe I over do it, but it makes it kind of fun to play with $140,000 sitting in the driveway everyday. We still work; so those precious minutes playing with those AGS buttons makes my day All kidding aside, when we do travel my confidence level on the RV is sky high. I use to think I was getting in over my head buying an RV versus just renting when I need. But I have come to learn my RV it is an Engineering Masterpiece that I just love.

I just have one of those cheap $86,500 Thor coaches. It doesn't require any maintenance other than normal service. It is my third RV, so it just another mobile toy like the golf cart, Vespa, and the two Corvairs. I do use Sta-Bil in the gas and drain the water after every trip. We do drive Hazel every month usually taking it out to a restaurant for carry-out dinning these days. My idea if a great trip is to put the top down on the 56 year old, one owner Corsa Convertible and take it through the Texas Hill Country to Bandera or Medina Lake for lunch, with with the DW of 58 years. Different strokes for different folks, so I hear.

[Jimbo56]

Originally Posted by dkoldman

I have a question for anyone that has to Prime before the generator will start? Do you have AGS; and if so; does it work? Meaning will it AUTO start by itself.

Why so many have to Prime just baffles me The question or focus may be on why is your genset is out of gas? If you have gone long periods of time that may explain it, but specify how long in between your last start? Could you have gas evaporating somewhere? If so; that could be very dangerous.

My guess is that on average my genset runs at least once every two weeks, but I manage to get 6 or 7 hrs a month. But I never have to Prime; and the genset starts in 3- 5 seconds everytime. Anybody run their genny equivalent to that, and it stills requires Priming?

I realize some may consider it normal to prime everytime, but there is a reason why? Out of gas or recent change of fuel filter are the only variables I know.

I do not have AGS. Must prime for count to 60.

[Jimbo56]

Back in the old days, a carbureted automobile had a diaphragm in the gas feed called a vacuum pump. It’s function was to hold gas up in the line to the carb so it didn’t take forever to start the car. You could tell when that little rubber diaphragm went bad by pulling the throttle link and being able to see gas go into the carb.

Does anyone know if an Onan 4000 has such a critter? I think not. Ace, Duck, Bob?

[16ACE27]

Originally Posted by Jimbo56

Back in the old days, a carbureted automobile had a diaphragm in the gas feed called a vacuum pump. It’s function was to hold gas up in the line to the carb so it didn’t take forever to start the car. You could tell when that little rubber diaphragm went bad by pulling the throttle link and being able to see gas go into the carb.

Does anyone know if an Onan 4000 has such a critter? I think not. Ace, Duck, Bob?

Pulling the throttle and seeing gas go in the carb is caused by the accelerator pump - a simple diaphragm pump integrated in the carb to richen the mixture on acceleration by squirting fluid from the bowl directly down the carburetor throat.

A vacuum pump is used on small engines and is also a simple diaphragm pump external to the carb to move gas to the carb from a fuel tank that is too low to gravity feed the carb. It is powered by the vacuum pulses in the engine and is simply a fuel pump.

Automobile engines before fuel injection mostly used a mechanical diaphragm fuel pump attached to the engine to suck gas from the tank and push it to the carburetor. They were normally attached to the engine itself and mechanically driven by a rod or lever that was driven from the camshaft.

All diaphragm pumps have inherent check valves that prevent fuel backflow so the fuel line would not empty unless the check valves leaked or the engine set so long that evaporation played a role is removing the standing fuel.

Electric fuel pumps are generally centrifugal pumps so when they are not running it is easy for fuel to drain back through them. Modern cars may have two fuel pumps and inline check valves to maintain fuel in the lines when not running.

I suspect the Onan does not have any inline check valves and the small bowl of the carburetor is easily emptied by driving and evaporation when the generator is not being used: hence the need to almost always prime the generator before staring. I would also suspect that if you dug into the circuitry and operation of an AGS that it does have a priming function that runs prior to simply starting the generator. I don't know that for sure but if I was designing one for an onboard generator that's the way I would do it.

[dkoldman]

Originally Posted by 16ACE27

I suspect the Onan does not have any inline check valves and the small bowl of the carburetor is easily emptied by driving and evaporation when the generator is not being used: hence the need to almost always prime the generator before staring. I would also suspect that if you dug into the circuitry and operation of an AGS that it does have a priming function that runs prior to simply starting the generator. I don't know that for sure but if I was designing one for an onboard generator that's the way I would do it.

Can we play this out? I have always been perplexed by the threads on this topic and never understood why so many have to prime. You and Beau388 have stated probably 95% of the reasons so that it now clear to me. It is clear now that they are out of gas; so the question is really why and is it a function of poor design?

But...

Reference your comment about AGS priming before starting. See my post #18 and the pictures above.

In the EC-30 design, the AGS sends the same start signal as the standard remote. So the Genny does not know if the remote is telling it to start, it's onboard switch, or the AGS. For the Genny to Prime it comes from another wire signal (Stop) that is continuous.

But lets say somehow it did know and Primed every time before trying to start anyway. Wouldn't priming every time the AGS called the Genny eventually cause other problems like flooding? It would also Prime every time you manually pressed start because it is sending the same signal to Genny.

I am going to guess that coaches like the 29M that have the genset close to the gas tank (within 4 feet) don't have this problem (phenomenon) if they use their Genny at least twice a month. But if I had coach that had an AGS that had this issue and would not AUTO START until after I manually started I would be pissed It makes me wonder if the Firefly system is advanced to know when it is called to start; to check the last runtime and decide if to prime before trying.? If not, that is the design I would target.

I will say this... every THOR coach I seriously looked at had a AGS system; and they all worked flawlessly to me (although that Magnum thing I would have hated based on what I know now). The AGS was the one thing my SOB coach did not come with from the factory; and it was something that I came to appreciate from TMC (especially the Firefly); and why I absolutely had to have.

[16ACE27]

Originally Posted by dkoldman

In the EC-30 design, the AGS sends the same start signal as the standard remote. So the Genny does not know if the remote is telling it to start, it's onboard switch, or the AGS. For the Genny to Prime it comes from another wire signal (Stop) that is continuous.

If the AGS can also turn OFF the generator it can send a STOP signal. It's up to the circuitry to determine how long to send that signal and as a PRIME signal instead of a STOP signal

Over priming the generator is not an issue as the carburetor still has a float and fuel inlet valve that prevents fuel flow into the bowl when it's not needed. Remember the fuel pump is always pushing fuel to the generator as if it was running at full load, even if it is running at no load.

[dkoldman]

Originally Posted by 16ACE27

If the AGS can also turn OFF the generator it can send a STOP signal. Yes that is PIN2 in the picture

It's up to the circuitry to determine how long to send that signal and as a PRIME signal instead of a STOP signal
Agree this is possibility, but for the Onan Remote Switch, the Onboard Switch it is clearly STOP/PRIME where you manually hold button for priming to occur. However on the EC-30 on the wiring schematic (also attached in post #18) it only shows a STOP output. So while I agree the circuitry could be calculating how long to hold PIN2, the manual specifically says when conditions warrants the AGS will send a Start Signal to Genny (nothing about a Pre Stop/Prime signal). If it was designed to Prime before sending that Start signal, that would be a big omission, especially when they also say you only need to Prime when out of gas or replacing fuel filter. I bet if I told the Marketing people what you are getting at, they would market this as some kind of Electronic Ignition System to make folks want to buy the EC-30 over the regular remote

Over priming the generator is not an issue as the carburetor still has a float and fuel inlet valve that prevents fuel flow into the bowl when it's not needed. Remember the fuel pump is always pushing fuel to the generator as if it was running at full load, even if it is running at no load. My lesson learned for today

My curiosity is at point now where I may have to call Onan. But during the interim until I can confirm the engineering behind it; I will keep on doing exactly what I doing now at a minimum; so mine keeps working.

This reminds me on another forum where subject was getting splashed with cold water in the shower, I hated it. There were all kinds of thoughts about why and how to fix diverters etc where many were saying the fixes did not work. Then one day my shower cartridges were leaking so versus replacing under warranty, I bought a new shower system very inexpensive and very nice looking. It not only fixed the leaking faucets, but it also fixed the cold water zapping But there were several that would NOT accept it; because they insisted the design of my new fixture was no different than the design of the one I replaced. Basically they were telling me I was still getting zapped with cold water, or I was never getting zapped with cold water to begin with

[dkoldman]

I just spoke with Cummins Support

They say that the EC-30 does have a software option to Prime Genny for (x) seconds duration if needed based on the design of the system (location of Gas tank to Genset etc.) So The ACE nails it again; so what else is new

They further state by Default this feature is turned OFF. (Cummins Onan EC-30)

They stated I did not need due to proximity of tank to genset for my coach and was concerned that I was wanting to change the setting ( I don't) despite me telling them multiple times my system was working perfectly; I guess they struggle with someone calling when everything was working

They also confirmed that Priming should NOT be required every time (design / location of genset notwithstanding). Genset should start 3 - 5 seconds, it is their opinion at least the support person I talked to today; that anyone that has to Prime; it is because they are not using the Genset, or exercising properly.

Conclusion: If I had an RV that Genset was not in close proximity of gas tank and I had to prime every time that would be considered as normal to have to manually prime. If that same coach had an AGS, it would need to be programmed (likely with Cummins Onan help) so if you need the AGS to work properly it would know to Prime every time automatically.

For me this bewilderment has now been resolved. I guess I just got lucky with a design that has the Genset 30" inches away from Gas Tank


1-800-CUMMMINS™
For more information visit care.cummins.com or call 1-800-CUMMMINS™ to speak to a Care representative.