NY_Dutch
Well-known member
About a month ago a fellow asked me to check out the Onan Marquis 7000 generator in his 1997 Coachmen Catalina that had stalled and wouldn't turn over. It didn't take long to figure out that the oil had been allowed to get low and engine had seized. A quick check found that a previous owner had bypassed the oil pressure switch. He asked about replacing it, and I found a newer used Emerald 5000 that would work well for him at a cost of $1800 plus shipping. He was getting ready to take a trip with the rig, and said he'd decide what to do when he got back. I said I'd try something before he went that might help when he got back but not get his hopes up. I pulled the spark plugs and loaded each cylinder with a mix of PB Blaster and 2-cycle oil. 2-cycle only because he had a spare quart on hand. He got back a couple of weeks ago, but I didn't get back to our site until yesterday.
This morning I went over with a pry bar and tried turning the flywheel. It finally gave about a quarter inch, so I started working it back and forth until it turned pretty easily. I draped a couple of rags over the plug openings and hit the starter button. I was pleased when it took off and spun quite freely, blowing much of the oil mix out. I replaced the plugs and filled the oil sump along with changing the filter, and hit the starter again. It took a couple of tries, but after a couple of false starts, it finally fired up with a great puff of smoke. A couple of minutes later the exhaust had cleared nicely, and another few minutes later I could no longer detect any burned oil smell in the exhaust. I just received a note from the fellow, and he ran the generator for about 4 hours with both A/C's running to load it, and it ran without a hitch. I told him to keep an eye on the oil level even after I installed a replacement pressure switch, but at this point I think we can put this one in the "Win" column. I've had this technique work on small single cylinder engines on occasion, but this was my first success on an Onan engine. Sorry VisoneRV, I think you lost a generator sale...
This morning I went over with a pry bar and tried turning the flywheel. It finally gave about a quarter inch, so I started working it back and forth until it turned pretty easily. I draped a couple of rags over the plug openings and hit the starter button. I was pleased when it took off and spun quite freely, blowing much of the oil mix out. I replaced the plugs and filled the oil sump along with changing the filter, and hit the starter again. It took a couple of tries, but after a couple of false starts, it finally fired up with a great puff of smoke. A couple of minutes later the exhaust had cleared nicely, and another few minutes later I could no longer detect any burned oil smell in the exhaust. I just received a note from the fellow, and he ran the generator for about 4 hours with both A/C's running to load it, and it ran without a hitch. I told him to keep an eye on the oil level even after I installed a replacement pressure switch, but at this point I think we can put this one in the "Win" column. I've had this technique work on small single cylinder engines on occasion, but this was my first success on an Onan engine. Sorry VisoneRV, I think you lost a generator sale...