Onan 4K generator shuts off

[safari]

Originally Posted by mstng

It’s staying on now and It will have a lot of chances to disappoint in the next couple of weeks during a 2 week trip coming up. I’m going to change plug and oil this week. Would oil viscosity maybe make a difference regarding heat. Should I use something higher than straight 30w. Would 10-40 have better performance if heat is the issue.

Hello,I get the Onan 15/40 from the Onan dealer so i know it is the correct oil,& I live in the warm California sun.

[Long & Winding road]

Yeah use the correct oil weight (15 w 40 or 15w - 50?).

I just switched to full synthtic oil in my generator. I get a lot of hours on mine so I figured it would help in the long run.

I use mine while driving when temps above 82 deg to keep the inside cool (plus it will be already cooled down when you get to the park or my favorite Mtn bike trail head(S). I have almost 200 hours on mine already. I change the air filter once a year and the plug every other year.

Our generator is just like a lawn mower engine (IMO). I dont know all of the tech terms and I dont pretend to know much about them.... but it uses the wind from the flywheel to blow air around the head (not water cooled) to keep it cool and this same wind blows on the flap to regulate the idle speed.

So check to make sure you dont have any nests or blockages around the engine that could cause it to over heat. Or blocking air flow to this idle speed flap.

If my lawn mower filter gets clogged bad with grass it will cause eratic idle.... clean some it and it runs perfectly. Not sure if this helps you or not.

Also check your high altitude ajustment. I looked at mine last week. It will say Zero on the left and I think like 3000 or 5000 on the right side. Well mine was at zero and my elevation were im at is 1300 feet so I move it up a little so )guess-it-mate 1000 ft) and it seems to run a smiggen better? It didnt run bad before but I seemed to smooth it out some? (Or that all could be in my head )

[16ACE27]

Originally Posted by Long & Winding road

Yeah use the correct oil weight (15 w 40 or 15w - 50?).

I just switched to full synthtic oil in my generator. I get a lot of hours on mine so I figured it would help in the long run.

I use mine while driving when temps above 82 deg to keep the inside cool (plus it will be already cooled down when you get to the park or my favorite Mtn bike trail head(S). I have almost 200 hours on mine already. I change the air filter once a year and the plug every other year.

Our generator is just like a lawn mower engine (IMO). I dont know all of the tech terms and I dont pretend to know much about them.... but it uses the wind from the flywheel to blow air around the head (not water cooled) to keep it cool and this same wind blows on the flap to regulate the idle speed.

So check to make sure you dont have any nests or blockages around the engine that could cause it to over heat. Or blocking air flow to this idle speed flap.

If my lawn mower filter gets clogged bad with grass it will cause eratic idle.... clean some it and it runs perfectly. Not sure if this helps you or not.

Also check your high altitude ajustment. I looked at mine last week. It will say Zero on the left and I think like 3000 or 5000 on the right side. Well mine was at zero and my elevation were im at is 1300 feet so I move it up a little so )guess-it-mate 1000 ft) and it seems to run a smiggen better? It didnt run bad before but I seemed to smooth it out some? (Or that all could be in my head )

Generators don't have an idle speed. Inverter generators have an "ECO" mode which lowers the running speed at lower loads but non-inverter generators run at the same (almost constant) speed to produce 60 Hz regardless of load.

[petefoss]

I found in very warm conditions it helps to prop the outer door open. Not the green panel in the generator but the locking coach panel that the generator hides behind.

[Long & Winding road]

Like I said I dont know that much but when you move that little arm connected to the throttle it acts like any lawn mower I own for 30+ years. It changes the idle speed and re-adjust its self when you let go.

Do inverter type gensets do this as well?

My mower senses thicker grass and ups the idle speed as well. Just like when the AC kicks on when running my Genny.... takes a coulple of seconds, boosts the idle... then its smooths out.

[mstng]

All great info guys and appreciated. I'm going to ride it out for now and will know soon if anything i did made a change. I may have used straight 30 which is in the range of recommendations and going to 10-40 may be just voodoo but will give it a try if needed. Wish I had known to open the outer door when I was having the problem and will try that if needed.

[16ACE27]

I'll be the lone dissenter here and say your generator did not shut down due to overheating. The generator makes heat when it is loaded so unloading it would not cause an increase in heat load and cause it to shut down; it would shut down while the A/C was running if it was overheating. The fact that it would shut down when the A/C compressor cycled off and this was a repeatable event makes me think your generator tripped off on overspeed. It does have an overspeed shutdown and when you suddenly dump load the speed will go up for 2 reasons:
1 - the loss of load until the governor reacts
2 - the speed droop which makes the generator run slightly slower as the load increases.

So it may not actually be overspeeding, but if the overspeed trip was adjusted too close to the normal running range of speed it could cause it to shutdown when it has not exceeded the overspeed parameter, but has exceeded the overspeed trip point.

[mstng]

That’s interesting info 16Ace27. If it comes to needing adjustment I assume it’s something that a shop would have to do.

[16ACE27]

Originally Posted by Long & Winding road

Like I said I dont know that much but when you move that little arm connected to the throttle it acts like any lawn mower I own for 30+ years. It changes the idle speed and re-adjust its self when you let go.

You're overriding the governor and changing the operating speed, not the idle speed.

Originally Posted by Long & Winding road

Do inverter type gensets do this as well?

If you override the governor, yes.

Originally Posted by Long & Winding road

My mower senses thicker grass and ups the idle speed as well. Just like when the AC kicks on when running my Genny.... takes a coulple of seconds, boosts the idle... then its smooths out.

Your governor senses the motor slowing down from the operating speed you have it set at. It compensates for the engine slow down by opening the throttle to speed the engine back up to the desired operating speed. The idle speed is not changed by the governor on a lawn mower, it is changed by the idle speed adjustment screw.

You are correct in that the generator engine and the lawnmower engine operate in the same way as operating speed is controlled by the governor, and the governor compensates for the load on the engine. The difference is that the generator has a fixed operating speed and the lawnmower has a user adjustable operating speed.

[Long & Winding road]

Originally Posted by 16ACE27

You're overriding the governor and changing the operating speed, not the idle speed.



If you override the governor, yes.



Your governor senses the motor slowing down from the operating speed you have it set at. It compensates for the engine slow down by opening the throttle to speed the engine back up to the desired operating speed. The idle speed is not changed by the governor on a lawn mower, it is changed by the idle speed adjustment screw.

You are correct in that the generator engine and the lawnmower engine operate in the same way as operating speed is controlled by the governor, and the governor compensates for the load on the engine. The difference is that the generator has a fixed operating speed and the lawnmower has a user adjustable operating speed.

Ok, thanks for the info.

I would still check for any nests around the engine (before you bring it in to a shop) to make sure its an issue. Also check the make sure no nest inside the air filter.

Perhaps you can lower the speed screw yourself if this "Overspeed" is the cause of your problems?

[Finch1408]

May sound weird. BUT, make sure the Altitude dial is in the Range of your altitude. It can play tricks on performance.

[Kgg]

Do not fill the oil all the way up on the dip stick my would shut off also I watch a u tube and a gentleman suggested to have the oil only a quarter way up and it worked for me carry extra oil to fill when at add

[sikorge]

Originally Posted by mstng

Hello all. I have a 2018 Vegas 24.1. After finally boondocking for a week I discovered the generator would shut off and not restart for 20-60 minutes.
Trouble shooting reveals it shuts off when the AC thermostat reaches the set temp and the compressor stops. I tried this at various thermostat temps and it verified.
Any ideas on what I can do to avoid this issue?
Thanks

Mstng, we have the same 24.1 model AXIS. We had the same generator start/stop issue. Under your entry steps are the Coach Batteries, to the left side of the batteries, there is a breaker switch that is the culprit the keeps tripping. The solution is to clean the switch and switch it back on. The genny will continue to run after starting after cleaning the breaker switch. Good luck.

[Junodtim]

Originally Posted by mstng

Hello guys, an update.
Back at it with the generator. Very hot day with temps close to 100 and unbearable humidity. Almost convinced that over heating must play a part as suggested in generator shutting off. Pulled some oil off down from the full mark to the add mark and its been running for over 2 hours with AC cycling on and off, no surges and no stopping. Whether this is coincidence or truly helped I have no idea. It was recommended elsewhere and some of you may have some insight to that. Time will tell if truly fixed.
Why it would start from the generator start switch but not from the cab switches I don't know. Low voltage perhaps? Cables are secured. It's fine now but has been plugged in for a week.

Thanks for your thoughts.

That was the solution for my 2005 Onan 4kw. The oil must be boiling or something. Our generator would shut down after 20 minutes while it was 90 degrees or warmer outside. Lowered the oil to the add mark on the dip stick solved all of generator problems. There is a lot of info on different forums.

[rtewdtew]

Hi, I'm Jerry. I'm not sure if my first post took, so I will re-do it. Long story short is that I had the same problem. I found an article on the Internet that talked about a built in design flaw. The person that wrote the article was very aggressive with his research and found that if the oil in the Onan 4 k generator was on the full mark, he had the same issue. He discovered that if he drained a small cup of oil out of the generator (just below the full mark) that the problem stopped. It sounded pretty far out, but I figured I had nothing to loose, so I gave it a try and low and behold....I have not had the problem any more. Seems to me that a redesigned dipstick could have saved a lot of us some grief. When I changed the oil in the Gen now, I leave it a half notch to notch below the full mark and just keep a check on it. It's along shot, but my service technicians are good and they could not find the problem, so I took it on myself and this worked for me. Nothing to loose if you know what I mean. Good luck.

Jerry & Diane
Thor Four-Winds 31W

[Boerne RV]

1. House battery 70% of the time
2. House battery 10% of the time
3. Fuel. 10% of the time. ( Filter, carb, pump, hose..)
4. House battery. 5% of the time
5. Minor 4% of the time. (Fuse/breaker, relay, oil level, post connection...)
6. Major malfunction 1% of the time ($$$$$$$$)

[gnach]

Originally Posted by Boerne RV

1. House battery 70% of the time
2. House battery 10% of the time
3. Fuel. 10% of the time. ( Filter, carb, pump, hose..)
4. House battery. 5% of the time
5. Minor 4% of the time. (Fuse/breaker, relay, oil level, post connection...)
6. Major malfunction 1% of the time ($$$$$$$$)

Please elaborate, I'm slow this morning, missing caffeine
.

[Lefty02]

Ditto on the oil level being the cause. I have a Freedom Elite 30FE, 4K Onan gen, which would shut down after 20-30 minutes in hot weather. Saw the same YouTube video suggesting to suck some oil out with a turkey baster. I did that 2 years ago and haven’t had a repeat issue since. I keep the level about midway between full and add lines.

[DFOUSS]

I have a 2019 freedom traveler that shuts down. I think you will find that the generator is overheating because the it is recycling the hot air that is coming from the heat of the generator. I have to leave the door of the generator compartment open on a hot day or mine will shut down and won’t start until the generator cools off. Very poor design on Thor’s part.

I am going to put a vent in the side of the compartment that will allow only fresh cooler outside air to be pulls in to the intake. Good luck.

[mstng]

A lot of smart and experienced people on here. I’ve learned a bit from all of you and thanks for taking the time to give your opinions. Learning things every day. Was looking for the breaker for the generator so thanks for that. Never noticed it when doing battery maintenance. Just changed the oil to 15w40 instead of the 30 I had and filled to below half. I’ll know soon if problem’s resolved. Curious if a lower viscosity has more, less or no difference with regards to heat and expansion causing an over oil pressure situation. Probably over thinking it...Will try with door open and closed to try to nail this down.