Generator overheating

[RoyB]

I replaced all but 2 feet of the line with hi-grade injection hose, ran the whole thing through R-6 foam insulation and relocated it to the outside of the frame away from the heated items. But the hose comes out of the tank at the center of the frame aft of the axle where all the heat from everything forward is channeled between the frame beams. I can't get to the last two feet before it goes into the tank, no room between axle and frame. I think that is where the problem exists, don't think I could ever get it wrapped with tape.

[Tgroves526]

I Have to ask a silly question, If Jayco Recognizes a Vented Compartment door is needed then why dont they retrofit our compartment door ? I noticed that many companies have a screen mesh for a area that the generator needs ventilation. At least give me a Part number of a professional door . My thoughts Ted

[RoyB]

The last week of the two year warranty (Onan) I contacted the corporate customer service department and got a commitment from them to replace the generator in my MH if the OKC Cummings shop could not make it run (July in Oklahoma). They had it in again for a week, changed multiple components, fuel pump, filter, oil filter, air filter, carburetor, control board, governor, etc. I was skeptical after two years of not working reliably but I picked it up and 30 minutes later got home, still running at 96 degrees. Next day took a road trip drove 2.5 hours out and 2.5 hours back, 90-96 degrees, ran fine the whole time. Recently took a overnight dry camp trip, temps 75 at night, mid 90s during the day, generator ran for 27 hours straight without a hiccup. Don't know which thing they did was the solution but after two years I have a generator. I'm happy and disappointed at the same time.

[conch02]

would not do vents in door. - ugly and would not do much good.. the 5500 is a bottom feeder. I have seen people put scoops on the bottom. design flaw with jayco and Cummins. Cummins does make a botton vent attachment. maybe you could get jayco to pay for it.

[4star]

First, I replaced the fuel pump. Still shut down. Then I moved the fuel pump outside the generator housing. Still shut down. Tried non-ethanol gas.. helped but still shut down. Then I insulated the line from the carb bowl to the tank. Better, but still shut down. Then I relocated the pump back towards the tank. Better again but would still shut down on hot days (~2 to 3 hours on 90+ days) then got fed up, took it out, drove it until the generator shut down. Pulled into a parking lot. Pulled the fuel line off the carb bowl fitting.. no gas
even while pressing the prime button. cut the line behind the generator where I verified the flow was still good (i was just going to keep cutting until i found good, non-vaporized gas and i do not recommend this lol). Relocated the fuel hose at the generator. Instead of the factory location of behind the generator in the hottest part of the steel channel, i ran it straight over the center and down into the generator and no shut down.... and I've tortured it since then. 92+ degrees. Over 100 hours on the generator troubleshooting it. Now it will not shut down unless I shut it down.

[SoCalSteve]

Jaycos latest fix for generator overheating while driving.

https://static.nhtsa.gov/odi/tsbs/20...32094-0001.pdf

Unfortunately the dealer on did half the steps and will be finishing the fix by adding Heat shield next month.

Gotta love these RV Techs, you give them all the info, work with Jayco motorized and they still can’t complete a simple fix.

[JudyB]

Also, running our generators with 10% ethanol is not good for them. An Onan tech suggested we try PURE gas as much as possible. Tried that and it worked much better.

[4star]

Running pure gas made a substantial difference in hot day run time on mine.

[hawkmaster]

Hi, By running pure gas are you refering to premium? At 8 miles a gallon that would drive trip costs up a lot.
Working in construction ive allways used portable generators. Just add stabil (gas treatmeant} I've used it in our MH for 2 years. Still have'nt had a problem with our
Onan 4400
Pete

[4star]

Originally Posted by hawkmaster

Hi, By running pure gas are you refering to premium? At 8 miles a gallon that would drive trip costs up a lot.
Working in construction ive allways used portable generators. Just add stabil (gas treatmeant} I've used it in our MH for 2 years. Still have'nt had a problem with our
Onan 4400
Pete

No, I'm talking about ethanol free gas. Yes it's more expensive but it doesn't boil as easily because it doesn't have ethanol in it. It allows the generator to run longer on hot days without shutting off. On a 98 degree day, in the rv on the road, with the family, having A/C is well worth the cost difference. In the winter I'll switch back to E10.

[Parrott]

Originally Posted by SoCalSteve

Jaycos latest fix for generator overheating while driving.

https://static.nhtsa.gov/odi/tsbs/20...32094-0001.pdf

Unfortunately the dealer on did half the steps and will be finishing the fix by adding Heat shield next month.

Gotta love these RV Techs, you give them all the info, work with Jayco motorized and they still can’t complete a simple fix.

Here’s another one.
https://static.nhtsa.gov/odi/tsbs/20...85378-0001.pdf

[4star]

Originally Posted by Parrott

Here’s another one.
https://static.nhtsa.gov/odi/tsbs/20...85378-0001.pdf

Mine came with that from the factory. Doesn't make any difference whatsoever. The fuel boils in the fuel line before it gets to the generator.

[Esqui]

Originally Posted by Bullet370

I have a new 29v precept and live in the south. The generator has not ran more than 20 minutes without stalling since i picked it up.
I visited a cummins dealer on a trip out west on 105 degree weather. They felt it was vapor locking due to heat and this made sence.
I finaly got ahold of jayco and they recomend a vent on the generator door to remove heat from compartment.
I have not done yet but do plan to put a fan with vent in to maximize flow. Runs great up north in 85 or below. When no ac is needed

I own a 2021 Alante 29F and have had the same issue for two and a half years. La Mesa RV in Port St Lucie, FL has performed all recalls and bulletins Jayco insists will fix the problem (added a vent and replace the compartment door), but it has not. When it first happened close to two and a half years ago, Jayco had me take it to Onan. Onan replaced the carburetor and fuel pump and that didn't fix the problem. I just returned from a trip to Islamorada in the Florida Keys and it shut down on the way to and on the return. I am done with Jayco. I am reaching out to my attorney tomorrow to see what are my option.

It is so frustrating to pay for something that hasn't worked for two and a half years....and for Jayco to be so indifferent about the matter because it only affects the customers in the south. I have given Jayco at lease 6 opportunities in a two and a half year span. That is more than fair. I live in the Ft. Lauderdale area so it is a bit of a drive up to Port St Lucie. Half the miles I have on the coach has been because of this issue.

I am thinking of selling it and stay clear of any other Jaycos.

[4star]

Originally Posted by Esqui

I own a 2021 Alante 29F and have had the same issue for two and a half years. La Mesa RV in Port St Lucie, FL has performed all recalls and bulletins Jayco insists will fix the problem (added a vent and replace the compartment door), but it has not. When it first happened close to two and a half years ago, Jayco had me take it to Onan. Onan replaced the carburetor and fuel pump and that didn't fix the problem. I just returned from a trip to Islamorada in the Florida Keys and it shut down on the way to and on the return. I am done with Jayco. I am reaching out to my attorney tomorrow to see what are my option.

It is so frustrating to pay for something that hasn't worked for two and a half years....and for Jayco to be so indifferent about the matter because it only affects the customers in the south. I have given Jayco at lease 6 opportunities in a two and a half year span. That is more than fair. I live in the Ft. Lauderdale area so it is a bit of a drive up to Port St Lucie. Half the miles I have on the coach has been because of this issue.

I am thinking of selling it and stay clear of any other Jaycos.

Agree 100% Sir. I debated whether to start fighting with them or not. If I did go that route, I wouldn't be able to use my motorhome for potentially years. I'm a mechanic, so I just fixed it myself. Life is too short for that bs. The problem is that ANY class a's or c's that use these generators have the same issue. I've read hundreds of posts from Thor, winnebago, jayco, fleetwood, you name it. It's a problem that revolves around cost and profits. They would have to engineer a solution at the factories to make sure no fuel vaporizes in any part of the fuel line when used in extremely hot weather. I guess they think that's too expensive. Nobody is going to run a generator for 2 hours in 95 degree heat BEFORE they sign the paperwork when they go and pick up their new motorhome. The dealer knows that, the factory knows that and so here we are.

If you're not mechanically inclined, what I would do is buy one of those hitch mounted utility racks, and a 4k generator from any hardware store. Strap the generator to the rack, plug your motorome into it and tie wrap the power cord up in several places. Then start bugging the dealer/factory about the onboard generator. That way you can use your motorhome until they do something (if they never do, fine, you can still enjoy it)

Kinda makes me sick just talking about it lol

[Esqui]

I thought about enclosing the compartment where the generator is. Maybe use some heat resistant board and wrap around it just leaving the exhaust underneath open so that the generator can only suck fresh air out of the vent on the compartment door? I'm no mechanic, but it appears that when it's too hot it is swallowing up all the heat off of the engine and the ground and shutting itself down to protect itself from overheating. By closing it, all that hot air from the engine in the ground should move passed it? Thoughts?

[4star]

Originally Posted by Esqui

I thought about enclosing the compartment where the generator is. Maybe use some heat resistant board and wrap around it just leaving the exhaust underneath open so that the generator can only suck fresh air out of the vent on the compartment door? I'm no mechanic, but it appears that when it's too hot it is swallowing up all the heat off of the engine and the ground and shutting itself down to protect itself from overheating. By closing it, all that hot air from the engine in the ground should move passed it? Thoughts?

The problem is the generator is in an enclosed box. The generator itself is creating the heat, plus all the surrounding heat. And because the fuel line runs so close to it and inside of it, boils or vaporizes the fuel. It only takes one small spot in the hose touching something hot to boil it there. It needs ambient air circulation all around the hot spots of the hose. Even 100 degree ambient isn't hot enough to boil fuel. But 200 internal degrees of the generator housing is. I have a wood stove temperature sensor zip tied to the inside of the generator. It gets as high as 220 degrees in there. I also have an oil temp probe that goes in the dipstick hole. Oil temp is only 150ish when it shuts down. Oil is good to at least 300 degrees (ive run 320 degrees for 100 laps in a dirt car) . The generator itself isnt even close to overheating mechanically. In my case, the fuel line runs across the back of the generator in channel steel that gets so hot you can't touch it. On my thermal camera, it gets to 180 degrees. THAT is more than enough to boil fuel. Even when you heat wrap it, that much heat will eventually heat soak the hose enough to boil the fuel.

First thing I did was move the fuel pump OUT of the genny housing. That helped a bunch. Then all the other things detailed in my other posts solved it. It's a combination of things, that, over time on extremely hot days creeps the fuel temp up enough to boil in the hottest spot in the hose. That spot on mine is on top, behind the generator in that steel channel.

I also had to pull from my experience racing dirt cars on 100 degree days where we had the same problems so I had a head start.

Also, these generators don't have over temperature protection so if it's a 36 code, it's probably fuel related and if the pump is running and there's no fuel getting to the bowl, bam.. vaporizing before it gets there.

When you get gasoline hot enough, it changes state from a liquid to a gas and the genny won't run off of anything other than liquid.

If you have the model of generator that has the drain screw under the bowl, when it shuts down, loosen the screw and run the pump with the prime button. Mine would have no fuel come out whatsoever. Hope this all makes sense

[SoCalSteve]

Jayco’s latest fix for the fuel vaporization. I’m still waiting for my dealer to get my parts in the test the fix to see if it solves the problem.

[4star]

Originally Posted by SoCalSteve

Jayco’s latest fix for the fuel vaporization. I’m still waiting for my dealer to get my parts in the test the fix to see if it solves the problem.

You can wrap it all you want, but if you leave the fuel hose where the factory routed it, it isn't going to help a bit. I've been there and done that.