Onan 7kw generator problem

SGSST109E · 10-20-2022, 07:25 PM

At the Dutch the generator was off when I returned to the trailer. Has gas and oil. Push to start and it starts then shuts right off. Any ideas???

cad · 10-21-2022, 12:07 PM

What code is displayed on the start switch when you attempt to re-start it?
Should be 3 3, then press stop once, and it will flash the actual code.

SGSST109E · 10-22-2022, 06:52 PM

Got a chance to check the code. It is 45.

voltdr · 10-23-2022, 12:36 AM

You didn’t mention how many hours are in it. Remove the brush holder. Shine a flash light into the hole. Crank the engine and see if the rotor is turning. If not, the belt or engine coupler is broken. The generator needs to make AC power to run.
Dan

SGSST109E · 10-23-2022, 04:52 PM

Thanks Dan, It has just over 2,000 hrs. It looks like they built the trailer around the generator. You can't even get the cover off to be able to get to the back of the generator. I am going to have to take the internal box apart to access the generator to work on it. Then make a new cover that would be removeable from the inside. The all aluminum trailer was built in 2008.

cad · 10-25-2022, 12:59 PM

My 2001 Onan cmm7000 efi is also putting out a 45 code... the rotor turns on mine while cranking. I checked the initial things that Rich Biebel recommended, and it ended with "best to have a pro look at it vs throwing money at it.".
Mine has 945 hours. Last time it ran was on a weekend when it was literally about 93 degrees, and I ran it all weekend with the AC on.

Keep us updated, as will I when I get a chance to get the trailer to the local repair shop. Mine is in the gooseneck....

btw... I believe Rich's phone is area code 973.... you may be able to run it up to him....

Clark

SGSST109E · 10-26-2022, 07:23 AM

I have a lot of work to do to make things accessable so it can be worked on. There is no way to get the cover off the generator the way its mounted in the nose of the gooseneck. I opening up the enclosure from the inside so the cover of the gneerator can be taken off. I am also going to look at raising it a few inches because the shield that covers the bottom to access the belt is inaccessable the way its mounted.

SGSST109E · 10-30-2022, 07:22 AM

Well I found out the only way to access the belt was to remove the generator from the trailer. I was able to lower the goose neck low enough to use a cherry picker to remove the generator. I have a shop crane in my garage to help me remove the engine assembly from the base. Unless you have the tools and equipment to do this job don't even try. The belt is burried behind the engine flywheel and the alternator. Its a small serpentine belt maybe 5\8" wide 4 ribs. I am freshing up all the hoses, tune up, valve adj etc. Order parts from the Onan website.

Dyno · 11-01-2022, 08:48 PM

My 7.5 Onan diesel would run 3-5 minutes then shut off. If I let it sit a while, it would restart then shut off again. I thought it was a fuel filter issue. I opened the lower access door and found the water pump belt broken. I replaced the belt and it runs fine. It is a terrible job to do. Once you get to the belt, that was easy. Getting the top and side covers off and on was the hard part. My arms look like I was playing with barb wire.

SGSST109E · 11-03-2022, 07:48 AM

My gas 7kw is air cool and you have to pull it out of the trailer to work on it. Removing the cover is extremely difficult to remove. Mine case has 4 torques screws holding it on. I am going to weld wing nuts to the top of the screws so the can be removed by hand. You can never reach the screws in the trailer cabinet with a ratchet unless you jack up the generator to get your hand in there.

10-20-2022, 07:25 PM	#1
SGSST109E Member Join Date: Jun 2007 Location: NJ Posts: 342 Likes: 54 Liked 124 Times in 58 Posts	Onan 7kw generator problem At the Dutch the generator was off when I returned to the trailer. Has gas and oil. Push to start and it starts then shuts right off. Any ideas???

10-21-2022, 12:07 PM	#2
cad Senior Member Join Date: Apr 2009 Location: Omaha, NE Posts: 673 Likes: 140 Liked 72 Times in 40 Posts	Re: Onan 7kw generator problem What code is displayed on the start switch when you attempt to re-start it? Should be 3 3, then press stop once, and it will flash the actual code.

10-22-2022, 06:52 PM	#3
SGSST109E Member Join Date: Jun 2007 Location: NJ Posts: 342 Likes: 54 Liked 124 Times in 58 Posts	Re: Onan 7kw generator problem Got a chance to check the code. It is 45.

10-23-2022, 12:36 AM	#4
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 700 Likes: 77 Liked 87 Times in 47 Posts	Re: Onan 7kw generator problem You didn’t mention how many hours are in it. Remove the brush holder. Shine a flash light into the hole. Crank the engine and see if the rotor is turning. If not, the belt or engine coupler is broken. The generator needs to make AC power to run. Dan __________________ Dan Foley SC 4698

10-23-2022, 04:52 PM	#5
SGSST109E Member Join Date: Jun 2007 Location: NJ Posts: 342 Likes: 54 Liked 124 Times in 58 Posts	Re: Onan 7kw generator problem Thanks Dan, It has just over 2,000 hrs. It looks like they built the trailer around the generator. You can't even get the cover off to be able to get to the back of the generator. I am going to have to take the internal box apart to access the generator to work on it. Then make a new cover that would be removeable from the inside. The all aluminum trailer was built in 2008.

10-25-2022, 12:59 PM	#6
cad Senior Member Join Date: Apr 2009 Location: Omaha, NE Posts: 673 Likes: 140 Liked 72 Times in 40 Posts	Re: Onan 7kw generator problem My 2001 Onan cmm7000 efi is also putting out a 45 code... the rotor turns on mine while cranking. I checked the initial things that Rich Biebel recommended, and it ended with "best to have a pro look at it vs throwing money at it.". Mine has 945 hours. Last time it ran was on a weekend when it was literally about 93 degrees, and I ran it all weekend with the AC on. Keep us updated, as will I when I get a chance to get the trailer to the local repair shop. Mine is in the gooseneck.... btw... I believe Rich's phone is area code 973.... you may be able to run it up to him.... Clark Last edited by cad; 10-25-2022 at 01:05 PM.

10-26-2022, 07:23 AM	#7
SGSST109E Member Join Date: Jun 2007 Location: NJ Posts: 342 Likes: 54 Liked 124 Times in 58 Posts	Re: Onan 7kw generator problem I have a lot of work to do to make things accessable so it can be worked on. There is no way to get the cover off the generator the way its mounted in the nose of the gooseneck. I opening up the enclosure from the inside so the cover of the gneerator can be taken off. I am also going to look at raising it a few inches because the shield that covers the bottom to access the belt is inaccessable the way its mounted.

10-30-2022, 07:22 AM	#8
SGSST109E Member Join Date: Jun 2007 Location: NJ Posts: 342 Likes: 54 Liked 124 Times in 58 Posts	Re: Onan 7kw generator problem Well I found out the only way to access the belt was to remove the generator from the trailer. I was able to lower the goose neck low enough to use a cherry picker to remove the generator. I have a shop crane in my garage to help me remove the engine assembly from the base. Unless you have the tools and equipment to do this job don't even try. The belt is burried behind the engine flywheel and the alternator. Its a small serpentine belt maybe 5\8" wide 4 ribs. I am freshing up all the hoses, tune up, valve adj etc. Order parts from the Onan website.

11-01-2022, 08:48 PM	#9
Dyno Senior Member Join Date: Dec 2002 Posts: 870 Likes: 917 Liked 605 Times in 177 Posts	Re: Onan 7kw generator problem My 7.5 Onan diesel would run 3-5 minutes then shut off. If I let it sit a while, it would restart then shut off again. I thought it was a fuel filter issue. I opened the lower access door and found the water pump belt broken. I replaced the belt and it runs fine. It is a terrible job to do. Once you get to the belt, that was easy. Getting the top and side covers off and on was the hard part. My arms look like I was playing with barb wire.

11-03-2022, 07:48 AM	#10
SGSST109E Member Join Date: Jun 2007 Location: NJ Posts: 342 Likes: 54 Liked 124 Times in 58 Posts	Re: Onan 7kw generator problem My gas 7kw is air cool and you have to pull it out of the trailer to work on it. Removing the cover is extremely difficult to remove. Mine case has 4 torques screws holding it on. I am going to weld wing nuts to the top of the screws so the can be removed by hand. You can never reach the screws in the trailer cabinet with a ratchet unless you jack up the generator to get your hand in there.