ONAN Marquis Gold 7000 Gas

voltdr · 08-04-2019, 03:16 PM

I removed the generator and reset the air gap for the coils. Now the generator is happy.....but not as happy as I am...........
Dan

Rich Biebel · 08-04-2019, 06:54 PM

The spark timing is fixed. The flywheel is keyed to the crank and has magnet inserts. I set the coil air gap with feeler gauges. They are magneto type coils and the small white wire is to ground them to stop the spark.

I have a sequence for doing the belt and tensioner and it’s pretty easy once you do as many as I have.

I made up some various tools to do these machines.

Flywheel puller plate , chain rig to lift upper section off base.

I pull engines off the base and split the case to replace the base gasket when one fails. Cleaning that mess under the base takes some time and a lot of chemicals. WD-40 works very well and some other solvents and eventually Brakecleen....

voltdr · 08-04-2019, 11:25 PM

There were some blind holes in the upper plate that I tapped for 3/8” eyebolts. I then made some straps to separate the 2 halves. When I removed the coils to remove the flywheel, I put the coils back but the air gap was at the maximum distance allowed by the adjustment in the bolts holes. After I reset the gap to .012” and reassembled the generator, it started and ran fine. Thanks again for the tips.
Dan

Rich Biebel · 08-07-2019, 05:53 PM

Did one today. Coupler broke. Pulled machine out yesterday afternoon after reinstalling an old BGE in an old motorhome.
Had it cleaned up and back together and running today by early afternoon.
Load tested it for a while.
Got sidetracked fixing another one with random shutdowns.
Replaced control board on that one.
Rain prevented me from reinstalling first one.
Will complete it tomorrow and then on to a diesel 5.5 and others waiting in the wings.
Pretty much non stop lately.....

Hacksaw · 08-09-2019, 09:52 AM

I think a valuable lesson can be learned here. Because most large coach style gensets are such an animal to r & r from the coach, it would be wise to take the extra time to test before you reinstall. Now a guy like Rich is set up for this and he routinely does this probably because he has been thru this problem before.

voltdr · 08-17-2019, 09:58 PM

I agree completely. While I don't have a way to load test the unit. Before I installed it the second time, I hooked up a fuel line and a battery and started it to make sure it was going to run. Yes, I should've done that the first time, but I was "certain" I had everything right..........LOL
Dan

voltdr · 09-07-2019, 11:30 AM

I wanted to give everyone an update on the generator repairs. Went to Bowling Green, then INDY. Genset worked perfectly. I adjust the governor for 62 Hz, no load, and everything worked like new. Thanks to Rich and all who made comments. Looking forward to another 7500+ more hours.
Dan

08-04-2019, 03:16 PM	#1
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: ONAN Marquis Gold 7000 Gas I removed the generator and reset the air gap for the coils. Now the generator is happy.....but not as happy as I am........... Dan __________________ Dan Foley SC 4698

08-04-2019, 06:54 PM	#2
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,315 Likes: 25 Liked 544 Times in 213 Posts	Re: ONAN Marquis Gold 7000 Gas The spark timing is fixed. The flywheel is keyed to the crank and has magnet inserts. I set the coil air gap with feeler gauges. They are magneto type coils and the small white wire is to ground them to stop the spark. I have a sequence for doing the belt and tensioner and it’s pretty easy once you do as many as I have. I made up some various tools to do these machines. Flywheel puller plate , chain rig to lift upper section off base. I pull engines off the base and split the case to replace the base gasket when one fails. Cleaning that mess under the base takes some time and a lot of chemicals. WD-40 works very well and some other solvents and eventually Brakecleen.... __________________ Rich Biebel S/C 1479 Stock 147R

08-04-2019, 11:25 PM	#3
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: ONAN Marquis Gold 7000 Gas There were some blind holes in the upper plate that I tapped for 3/8” eyebolts. I then made some straps to separate the 2 halves. When I removed the coils to remove the flywheel, I put the coils back but the air gap was at the maximum distance allowed by the adjustment in the bolts holes. After I reset the gap to .012” and reassembled the generator, it started and ran fine. Thanks again for the tips. Dan __________________ Dan Foley SC 4698

08-07-2019, 05:53 PM	#4
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,315 Likes: 25 Liked 544 Times in 213 Posts	Re: ONAN Marquis Gold 7000 Gas Did one today. Coupler broke. Pulled machine out yesterday afternoon after reinstalling an old BGE in an old motorhome. Had it cleaned up and back together and running today by early afternoon. Load tested it for a while. Got sidetracked fixing another one with random shutdowns. Replaced control board on that one. Rain prevented me from reinstalling first one. Will complete it tomorrow and then on to a diesel 5.5 and others waiting in the wings. Pretty much non stop lately..... __________________ Rich Biebel S/C 1479 Stock 147R

08-09-2019, 09:52 AM	#5
Hacksaw Senior Member Join Date: Sep 2016 Posts: 884 Likes: 208 Liked 311 Times in 175 Posts	Re: ONAN Marquis Gold 7000 Gas I think a valuable lesson can be learned here. Because most large coach style gensets are such an animal to r & r from the coach, it would be wise to take the extra time to test before you reinstall. Now a guy like Rich is set up for this and he routinely does this probably because he has been thru this problem before.

08-17-2019, 09:58 PM	#6
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: ONAN Marquis Gold 7000 Gas I agree completely. While I don't have a way to load test the unit. Before I installed it the second time, I hooked up a fuel line and a battery and started it to make sure it was going to run. Yes, I should've done that the first time, but I was "certain" I had everything right..........LOL Dan __________________ Dan Foley SC 4698

09-07-2019, 11:30 AM	#7
voltdr Senior Member Join Date: Jan 2008 Location: Texas Posts: 706 Likes: 77 Liked 100 Times in 51 Posts	Re: ONAN Marquis Gold 7000 Gas I wanted to give everyone an update on the generator repairs. Went to Bowling Green, then INDY. Genset worked perfectly. I adjust the governor for 62 Hz, no load, and everything worked like new. Thanks to Rich and all who made comments. Looking forward to another 7500+ more hours. Dan __________________ Dan Foley SC 4698